Interspecific competition between Solenopsis invicta Buren and eight other ant species

Interspecific competition between Solenopsis invicta Buren and eight other ant species | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Interspecific competition between Solenopsis invicta Buren and eight other ant species Wenqiu Zhang, Lu Jiang, Mianchang Cheng, Yijuan Xu, Jun Li This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9183057/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Solenopsis invicta Buren is one of the most important invasive pests in China and competes aggressively with native ants. This study investigated competitive interactions between eight ant species and S. invicta , and the defensive chemicals involved, using individual and group competition tests and toxicity bioassays. Results showed that Tapinoma melanocephalum exhibited the lowest attack frequency against S. invicta in individual contests, while Pheidole megacephala caused low mortality in group trials. Camponotus japonicus showed the highest level IV attack intensity and caused the highest mortality, followed by Oecophylla smaragdina . Camponotus nicobarensis and Camponotus pseudoirritans achieved the highest mortality at a 1:1 ratio. Mortality caused by Polyrhachis dives and Anoplolepis gracilipes decreased with increasing numbers of S. invicta . Blocking acid gland pores significantly reduced mortality by these dominant species. Toxicity tests indicated that hexadecane had the strongest fumigation toxicity, while hexadecane and nonadecane showed the highest contact toxicity. These findings suggest that several native ant species can competitively suppress S. invicta , and their defensive pheromones play a key role. Utilizing such native ants could contribute to integrated management of S. invicta . S. invicta other ants competition confrontation pheromones Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Solenopsis invicta is an important invasive ant species that not only adversely affects agricultural production, public facilities, and public health but also causes considerable damage to the ecological environment in invaded areas (Nattrass and Vanderwoude 2001 ; Wanandy et al. 2022 ). Invasion by Solenopsis invicta has a severe negative effect on the species diversity and richness of local arthropods, such as spiders and ants, and can reduce the species richness of native ants by more than 33% (Jiang et al. 2010 ; Song et al. 2010 ; Wu et al. 2010 ; Lu et al. 2012 ; Huang et al. 2012 ; Qi et al. 2015 ; Wylie and Janssen-May 2017 ; Wang et al. 2024 ). Additionally, S. invicta can change the foraging and attack behavior of some native ants and has significant negative effects on the characteristics and structure of the arthropod community in banana plantations and lychee orchards (Huang 2016 ; Cheng et al. 2019 ; Xi et al. 2010 ; Wang et al. 2017 ). Interspecific competition often occurs in nature. Severe interspecific competition leads to competitive displacement, leading not only to the replacement of rivals but also to a decrease in species diversity, thereby affecting the entire ecosystem (Cardinale et al. 2006 ; Gao and Reitz 2017 ; Goodsman et al. 2018 ; Cui et al. 2022 ; Dang et al. 2022 ). Invasive ants compete with native ants with similar ecological niches for food resources and territories (Buczkowski and Bennett 2008 ). The destruction of indigenous ant colonies due to invasion and colonization by S. invicta has become an ecological issue that has attracted considerable attention. Several studies have shown that S. invicta coexists with a variety of other native ants; furthermore, native ants that coexist with S. invicta have strong competitive abilities and can resist competition by invasive ants. The coexistence mechanism between Monomorium minimum and S. invicta in the southeastern United States involves differences in heat tolerance (Adams and Traniello 1981 ; Bujan et al. 2016 ), allowing them to occupy different ecological niches in high-temperature environments. There are studied the competition between P. dives and S. invicta and reported that P. dives strongly attacked S. invicta and that P. dives inhibited the expansion of S. invicta to a certain extent (Li and Yang 2020 ). On the basis of the literature, eight different ant species ( Oecophylla smaragdin , Polyrhachis dives , Camponotus japonicus , Anoplolepis gracilipes , Camponotus nicobarensis and Camponotus pseudoirritans , Tapinoma melanocephalum and Pheidole megacephala ) that are widely distributed in Guangzhou, they were selected to study their interspecific competition with S. invicta (Zhao 2009; Ran 2011 , 2012 , 2013 ). The difference in mortality between these species and S. invicta during competition was analyzed, and the acidopore were sealed to determine the auxiliary effect of venom on attack by the test ants on S. invicta , thus revealing the importance of chemical attack in the competition between local ants and S. invicta . When an integrated control strategy for S. invicta in different habitats is considered, the number of local ants and other native species can be increased, the population number of S. invicta in the invaded area can be reduced through competition and confrontation, and the resistance effect of local ants can be fully exerted. The chemical substances secreted by local ants that compete with S. invicta were analyzed to reveal the function and efficacy of the secretions in the competition and confrontation processes, provide a theoretical basis for the development of new bioderived agents, and provide guidance for new approaches to control S. invicta . Materials and methods 1.1 Insects Ten S. invicta colonies were collected from Gangwei Village, Baiyun District, Guangzhou City (113°23'E, 23°22'N). The collected S. invicta colonies were placed into plastic buckets coated with talcum powder for 2–3 days until they nested stably in the buckets. The dripping method was used to extract the ant colonies from the soil (Chen 2007 ). Water was slowly dripped into the buckets with constant observation of the water level. The ants moved to the top of the soil and floated or formed a “raft” on the surface of the water. The ants were scooped out and placed in plastic boxes (340 mm×270 mm×130 mm), wherein the inner walls of the boxes were coated with talcum powder and reared on ham sausage and 10% sugar water for seven days. The room temperature ranged from 23 to 28°C, and the humidity ranged from 60 to 70%. The remaining ants were collected from other areas of Guangdong Province. Three O. smaragdina colonies were collected from Hetian Town, Luhe County, Shanwei City (115°39′E, 23°18′N). Three P. dive colonies were collected from Chengxi Village, Enping District, Jiangmen City (112°17′E, 22°10′N). Three C. japonicus colonies were collected from Ruyuan County, Shaoguan City (113°16′E, 24°46′N). Three C. nicobarensis colonies were collected from Yunfu City, Guangdong Province (112°02′E, 22°55′N), China. Three C. pseudoirritans colonies were collected from Heyuan City, Guangdong Province (114°41′E, 23°44′N). Three A. gracilipes colonies were collected from Dapeng New District, Shenzhen City, Guangdong Province (114°28′E, 22°35′N). Three T. melanocephalum and P. megacephala colonies were collected from Xihutang Village, Baiyun District, Guangzhou City (113°23′E, 23°19′N). The collected ant nests were placed in plastic boxes coated with talcum powder and fed 20% sugar water daily. The room temperature was 25 ± 2°C and the humidity was 80 ± 5%. And there are quarantine measures and anti-escape measures in the laboratory. 1.2 Competition evaluation 1.2.1 Individual attack tests A transparent container with a diameter of 15 mm and a length of 15 mm was placed on white paper. This container was used to observe the aggressive behavior of the ants. During the test, two ants of different species were placed in an observation container with soft tweezers, and the aggressive behavior of the ants was observed at close range with the naked eye (Fig. 1 ). According to the literature review, attack intensity was divided into the following four levels: Grade I, Grade II, Grade III, Grade IV, detailed in Table 1 (Suarez et al. 2002 ; Grangier et al. 2006 ). Small (head width 1.35 mm) S. invicta worker ants were paired with other ants at a ratio of 1:1 for a total of three treatments, each group was repeated in three ant nests, with each ant nest repeated 10 times, totaling 30 repetitions per group. Additionally, each group was observed for 5 minutes consecutively. Table 1 Individual Attack Level Classification Table Level I II III IV short-term antennal contact (< 1 s) long-term antennal contact (≥ 1 s) one party tilted its abdomen up, opened the mandible in a threatening posture, or quickly climbed to the other party’s back two parties attacked and became entangled with each other, or one party violently attacked the other party with its mandible or stinger 1.2.2 Group attack tests The ratios of S. invicta to other ants used were 5:1, 3:1, 3:2, 1:1, 2:3, 1:3, and 1:5 (the number of S. invicta was always 15). The ants were placed in a box using soft tweezers. After 1 min of adaptation, S. invicta were placed in a small box (Fig. 2). Observed the death of two test ants within 30min, judged the dead or unable to stand ants within 1 hour as dead individuals, and recorded the number of deaths of S. invicta and other ants respectively, and the test was repeated 15 times independently for each group, each type of ant repeated three nests. 1.3 Sealing the acidopore After the test described in Section 1.2 , the ends of the abdomens of the tested ants were sealed with nail polish (Orange, white) (Lebrun et al. 2014 ), and the glands of the other parts were not sealed. This sealing prevented the ants from secreting venom, thus revealing the importance of chemical attack by the test ants when fighting S. invicta , and clarifying the function of the test ant venom in attack behavior. The setting experiment is as follows: (i), take 10 heads of the other six kinds of ants, applied nail polish on their abdomens, and leaved them for 2 hours without putting S. invicta to find out whether the nail polish is harmful to ants; (ii)The acidpore at the end of the abdomen of other ants were blocked with nail polish, and a competition control was set up with S. invicta at a ratio of 1:5, using the method described in 1.2.2 (iii) A false blockage was created by applying a dot of nail polish on the side of the abdomen, and a competition control was set up with red imported fire ants at a ratio of 1:5, using the same method as above. 1.4 Analysis of glandular compounds 1.4.1 Extraction of ant glands Twenty ants of each of the six species were selected and placed in a foam box filled with ice cubes for sacrifice. The venom and Dufour glands were subsequently extracted under a dissecting microscope. The glands were placed into a 4-mL glass vial containing n-hexane (0.5 mL) and soaked with a glass rod at room temperature for 10 min. Then, the extract was filtered into a clean 4-mL vial via a glass pipette. Each type of ant was tested three times. 1.4.2 GC‒MS conditions The instrument used was an Agilent GC-MS (7890 B, G3440B, 2017) with an HP-5 column. The temperature program was as follows: 50°C for 5 min, increased in 10°C increments until it reached 280°C, and maintained for 10 min. The injector port, ion trap, and transfer line temperatures were set to 250, 200, and 280°C, respectively. 1.5 Toxicity test for each reagent According to the analysis of GC-MS results, the purchased standard samples of the major compounds were used to perform contact toxicity and fumigation toxicity tests for these substances in the glands, respectively (Table 2 ). Acetone was used as the solvent. Table 2 Chemicals used in the experiment Material name Purity level (%) Supplier Decane 98% Macklin, China Undecane ≥ 98% Macklin, China Tridecane ≥ 98% Macklin, China Tetradecane 98% Macklin, China Pentadecane 98% Macklin, China Hexadecane AR, 98% Macklin, China Cetene 94% Macklin, China Heptadecane AR, 95% Macklin, China Nonadecane AR, 98% Macklin, China Eicosane AR Macklin, China Heneicosane GC, > 99% Macklin, China 13-Docosenamide CP Macklin, China Acetone AR Guangzhou Chemical Reagent Factory, China ①Fumigation method. According to the concentration range of the agents to be tested in the preliminary experiment, the reagents were serially diluted with acetone solution to five concentrations: 12.5 mg/L, 6.25 mg/L, 3.13 mg/L, 1.56 mg/L, and 0.78 mg/L. For this experiment, 250-mL glass bottles were used as the fumigation chamber. The test ants were placed in glass bottles for approximately 10 min. Then, 20 µL of the test solution was coated onto the paraffin film, and the glass bottle was sealed with the treated side. The upper part of the bottle was coated with talcum powder to prevent the ants from coming into contact with test substances. The test was performed on three ant nests, and each group was tested 3 times with 20 worker ants. The number of deaths due to S. invicta was recorded at 6, 12, and 24 h. Because fumigation method is done in the bottle, it is best to observe the ants within it, the worker ants were considered dead if they curled. ②Topical application. Based on the concentration range of the agents to be tested in the preliminary experiment, each reagent was diluted with acetone solution to the same five test concentrations as those used in the fumigation method. One microliter of each drug mixture at different concentrations was placed on the pronota of large S. invicta worker ants via a microsampler, and the ants were then transferred to a plastic bowl, whose inner wall was coated with talcum powder (to prevent S. invicta from escaping the bowl). The acetone treatment was used as the control. Three replicates were performed for each concentration, and 15 worker ants were used in each replicate. Tests were performed on three ant nests. After 24 and 48 h of treatment, the number of worker ants that died was recorded. If worker ants were unable to stand up and move after being lightly touched with tweezers or had fewer than three legs, they were classified as dead. 1.6 Statistical analysis The data in this study were analyzed using Excel 2010 and SPSS Statistics 26.0. GraphPad Prism 8 software were used for graphing. Data that conforms to a normal distribution and homogeneous variance were analyzed using a one-way analysis of variance (ANOVA). Tukey’s test was used for multiple comparisons. The Tamhane's test Kruskal-Wallis test was used to test for non-normally distributed data. Then perform a Kruskal-Wallis single-factor analysis for multiple comparisons, and take the results of the Bonferroni multiple comparison test. Some data were analyzed using the independent samples T-test. For the toxicity test part, LC values, KT values, and LD values were calculated, using the Probit and Logit models. where N I, N II, N III, and N IV are the number of behaviors at the corresponding attack level. M = (U/N)×100% (2) where M is the mortality rate, U is the number of dead ants after testing, and N is the number of ants before testing. Results and analysis 2.1 Individual attack test 2.1.1 Attack levels between different ants and S. invicta Table 3 shows that both the total number of attacks and the number of level IV attacks by T. melanocephalum are the lowest. The total number of attacks is significantly lower than that of four ant species: P. dives , C. japonicus , C. nicobarensis , and A. gracilipes ( p = 0.03, p = 0.004, p < 0.001, p < 0.001). The number of level IV attacks is significantly lower than that of the other seven ant species ( p < 0.001). Combined with Fig. 3, it also has the lowest proportion in the Grade IV of small, medium, and large S. invicta , which are 5.38%, 21.21%, and 11.11% respectively. The number of low-level attack (I, II) behaviors of O. smaragdina is the lowest, which is significantly lower than that of the other seven ant species ( p < 0.001). Its proportions of the Grade I and II of small, medium, and large S. invicta are also the lowest, which are 13.73%, 16.04%, and 17.36% respectively. Table 3 Individual attacks numbers between eight ant species and S. invicta of different sizes. O. smaragdina Total number of attacks Number of attacks (IV) Number of attacks (I, II) 3.66 ± 0.30 cd 2.02 ± 0.23 abc 0.58 ± 0.07 d P. dives 4.49 ± 0.29 bc 1.83 ± 0.15 bc 1.72 ± 0.18 bc C. japonicus 4.88 ± 0.34 abc 2.78 ± 0.24 a 1.17 ± 0.11 c C. nicobarensis 6.44 ± 0.45 a 2.40 ± 0.22 ab 2.61 ± 0.26 ab C. pseudoirritans 3.71 ± 0.24 cd 1.49 ± 0.17 c 1.50 ± 0.13 c A. gracilipes 5.54 ± 0.35 ab 1.58 ± 0.19 bc 2.51 ± 0.16 a T. melanocephalum 3.01 ± 0.34 d 0.32 ± 0.08 d 1.86 ± 0.24 abc P. megacephala 3.57 ± 0.25 cd 1.86 ± 0.14 bc 1.46 ± 0.14 c The data in the table represent the mean ± standard error (SE) of 30 repetitions. The data with different letters indicate significant differences at a level of 0.05. (There is unequal variance, and the Tamhane test result shows that p < 0.05). 2.1.2 Attack index between different ants and S. invicta The results of the attack index analysis (Table 4) revealed that the attack index of C. nicobarensis against small S. invicta workers was significantly greater than that against large workers ( p = 0.019). The attack indices of the remaining seven ant species and S. invicta of different sizes did not differ significantly. Regardless of size, overall, O. smaragdina and S. invicta workers had the highest attack indices. The attack index of T. melanocephalum was the lowest, significantly lower than that of the other seven ant species (with p = 0.016 compared to A. gracilipes , and p < 0.001 for the others). The attack index of A. gracilipes also showed significant differences with the other 5 ant species except C. pseudoirritans (with p = 0.002 compared to C. nicobarensis , and p < 0.001 for the others). The data in the table represent the mean ± standard error (SE) of 30 repetitions. The data in the first three columns were compared, and data with different letters indicate significant differences at a level of 0.05 (Tukey test, p < 0.05). The data in the last column are compared longitudinally, and data with different letters indicate that the difference is significant at the 0.05 level (Tamhane test, p < 0.05). 2.2 Swarm attack tests As shown in Fig. 4, there are statistical differences in the mortality rate of other ants to S. invicta in different proportions, including 5:1 ( H = 73.745, p < 0.001); 3:1 ( H = 86.296, p < 0.001); 3:2 ( H = 85.979, p < 0.001); 1:1 ( H = 90.923, p < 0.001); 2:3 ( H = 85.833, p < 0.001); 1:3 ( H = 94.604, p < 0.001); 1:5 ( H = 84.025, p < 0.001). Regardless of the ratio, the mortality rate of S. invicta caused by C. japonicus is the highest, while that caused by T. melanocephalum is the lowest. The mortality rates of S. invicta caused by O. smaragdina , C. japonicus , P. dives , A. gracilipes , and T. melanocephalum gradually decrease as their numbers decrease. The mortality rate of S. invicta caused by T. melanocephalum is significantly lower than that caused by O. smaragdina , C. japonicus , and A. gracilipes under all ratios ( O. smaragdina : p < 0.001, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p = 0.001, p < 0.001; C. japonicus : all p < 0.001; A. gracilipes : p < 0.001, p = 0.003, p = 0.005, p < 0.001, p = 0.001, p < 0.001, p = 0.001). Meanwhile, under the ratios where the number of other ants is reduced, namely 1:1, 2:3, 1:3, and 1:5, it is also significantly lower than that caused by C. nicobarensis and C. pseudoirritans ( C. nicobarensis : p < 0.001, p = 0.003, p < 0.001; C. pseudoirritans : p < 0.001, p < 0.001, p = 0.006, p = 0.022). The mortality rate of S. invicta caused by P. megacephala is significantly lower than that caused by O. smaragdina and C. japonicus under all ratios ( O. smaragdina : p < 0.001, p < 0.001, p < 0.001, p < 0.001, p < 0.001, p = 0.013, p = 0.012; C. japonicus : all p < 0.001). The mortality rate caused by P. dives is significantly higher than that caused by T. melanocephalum and P. megacephala under the ratios of 5:1, 3:1, and 3:2 ( T. melanocephalum : all p < 0.001; P. megacephala : p = 0.001, p < 0.001, p = 0.002). Moreover, under the ratios of 1:1, 2:3, 1:3, and 1:5, it is lower than that caused by C. japonicus (all p < 0.001). As shown in Fig. 5, there are statistical differences in the mortality rates of other ants in different proportions, including 5:1 ( H = 95.749, p < 0.001); 3:1 ( H = 86.472, p < 0.001); 3:2 ( H = 80.087, p < 0.001); 1:1 ( H = 81.692, p < 0.001); 2:3 ( H = 66.669, p < 0.001); 1:3 ( H = 83.642, p < 0.001); 1:5 ( H = 80.056, p < 0.001). Regardless of the ratio, the mortality rate of P. megacephala in group competition was significantly higher than that of P. dives , C. japonicus , C. nicobarensis , and C. pseudoirritans ( P. dives : all p < 0.001; C. japonicus : all p < 0.001; C. nicobarensis : except for the 1:5 ratio with p = 0.001, all p values for other ratios were < 0.001; C. pseudoirritans : all p < 0.001). The mortality rate of T. melanocephalum was significantly higher than that of O. smaragdina , P. dives , C. japonicus , C. nicobarensis , and C. pseudoirritans in the proportional ratios of 5:1, 3:1, and 3:2 ( O. smaragdina : p < 0.001, p = 0.002, p = 0.002; P. dives : all p < 0.001; C. japonicus : all p < 0.001; C. nicobarensis : p = 0.001, p = 0.006, p = 0.001; C. pseudoirritans : p < 0.001, p = 0.023, p = 0.013). The mortality rate of A. gracilipes in the 1:3 and 1:5 ratios was significantly higher than that of P. dives , C. japonicus , C. nicobarensis , C. pseudoirritans , and T. melanocephalum ( P. dives : p = 0.001, p < 0.001; C. japonicus : p < 0.001, p < 0.001; C. nicobarensis : p < 0.001, p = 0.001; C. pseudoirritans : p < 0.001, p < 0.001; T. melanocephalum : p < 0.001, p < 0.001). The mortality rate of O. smaragdina in the 1:1 and 2:3 ratios was significantly higher than that of P. dives , C. nicobarensis , and C. pseudoirritans ( P. dives : p = 0.004, p = 0.035; C. nicobarensis : p = 0.004, p = 0.045; C. pseudoirritans : p = 0.008, p = 0.002). 2.3 Sealing the acidopore Since the mortality rate of T. melanocephalum and P. megacephala against S. invicta is very low, these two species of ants will no longer be used in subsequent experiments. The other six ants with nail polish and no S. invicta compete, there is no mortality rate after 2h. Table 5 shows that after the acidopore was sealed, the mortality of S. invicta caused by O. smaragdina and C. nicobarensis significantly decreased ( t = 2.626, p = 0.014; z =-3.021, p = 0.003), whereas the mortality of O. smaragdina and C. nicobarensis significantly increased ( z =-3.467, p = 0.001; z =-3.624, p < 0.001). No significant difference was observed in the mortality of S. invicta caused by P. dives ( z =-0.172, p = 0.863). The mortality rate of P. dives was low ( z =-0.703, p = 0.482). The mortality of S. invicta caused by C. japonicus significantly decreased ( z =-2.827, p = 0.005), but the difference in the mortality of C. japonicus was not significant ( z =-1.548, p = 0.122); both rates decreased. With the nail polish sealant, C. pseudoirritans caused more S. invicta deaths than without the nail polish sealant ( z =-2.44, p = 0.015), and the mortality of C. pseudoirritans also significantly increased ( z =-3.097, p = 0.002). The mortality of S. invicta caused by A. gracilipes was significantly reduced ( t = 3.666, p = 0.001), whereas the difference in mortality of A. gracilipes after sealing was not significantly greater ( z = 0, p = 1). Lowercase letters in the table indicate that the data in the first two columns and the last two columns were compared (If the data follows a normal distribution, the independent sample T-test was used; otherwise, a non-parametric test is used, p < 0.05). Capital letters indicate that the data in the same column are compared (Kruskal-Wallis single-factor analysis with multiple comparisons test, p < 0.05). Data with different letters are significantly different at the 0.05 level. There are statistically significant differences in the mortality rates between S. invicta and other ants when nail polish was applied to the acidopore at the end of the abdomen and to the lateral position of the abdomen, among which S. invicta ( H = 47.917, p < 0.001; H = 50.055, p < 0.001); other ants ( H = 61.404, p < 0.001; H = 54.503, p < 0.001). The lethality of O. smaragdina , P. dives , and A. gracilipes against S. invicta was significantly lower than that against C. japonicus (acidopore: p = 0.001, p < 0.001, p < 0.001; false blockage: p = 0.002, p < 0.001, p < 0.001), regardless of the presence or absence of nail polish sealant. The mortality rates of P. dives , C. japonicus , and C. pseudoirritans were significantly lower than those of A. gracilipes with or without nail polish (acidopore: p < 0.001, p < 0.001, p = 0.009; false blockage: p < 0.001, p < 0.001, p < 0.001). 2.4 Identification of substances in the secretions of the Dufour glands and venom glands GC-MS revealed that the secretions of the Dufour glands and venom glands of the six ant species were mainly composed of alkanes supplemented by a few acids. As shown in Table 6, almost all pheromones secreted by the glands appeared earlier, and individual peaks with higher values appeared later. The main volatile components were decane, undecane, tridecane, tetradecane, pentadecane, hexadecane, hexadecene, heptadecane, nonadecane, eicosane, hexacane, and erucamide; among these components, undecane and tridecane were present in the secretions of all six ant species. 2.5 Comprehensive Analysis of Compound Toxicity to S. invicta at Different Fumigation Durations In the Probit model analysis of 6 h fumigation LC₂₀, 12 h fumigation LC₅₀, and 24 h fumigation LC₉₀, the toxicity of tested compounds to S. invicta generally increased with prolonged exposure time, and there were orders-of-magnitude differences in toxicity among compounds. At 6 h(Table 7), hexadecane exhibited the strongest toxicity (LC₂₀ = 0.49 mg/L), followed by decane (4.00 mg/L) and tetradecane (5.30 mg/L), while nonadecane (2,337,743.97 mg/L) and heneicosane (9686.93 mg/L) showed extremely weak toxicity. When the fumigation duration was extended to 12 h༈Table 8༉, the overall toxicity was enhanced: hexadecane remained a highly toxic representative (LC₅₀ = 0.00 mg/L), and the LC₅₀ values of decane (0.01 mg/L), tetradecane (0.08 mg/L), and eicosane (0.52 mg/L) were all below 1 mg/L; in contrast, heneicosane (5,620,049,434,643.50 mg/L) and nonadecane (6966.67 mg/L) still displayed low toxicity. Table 7 LC20 values of different compounds for fumigating S. invicta at the 6th Substance Slope ± SE LC20(mg/L) 95% CI Undecane 0.36 ± 0.12 12.19 5.86–191.50 Tridecane 0.32 ± 0.12 8.72 4.26-128.17 Pentadecane 0.09 ± 0.12 91.77 Heptadecane 0.37 ± 0.13 23.38 9.24-1695.45 Decane 0.22 ± 0.11 4.00 0.33-408755538079687420.00 Tetradecane 0.30 ± 0.12 5.30 2.43–36.59 Hexadecane 0.45 ± 0.10 0.49 0.09–0.99 Cetene 0.21 ± 0.14 1416.67 Eicosane 0.43 ± 0.12 9.76 5.43–44.27 Nonadecane 0.16 ± 0.19 2337743.97 Heneicosane 0.23 ± 0.17 9686.93 13-Docosenamide 0.33 ± 0.19 2766.23 At 24 h(Table 9), the toxicity of highly toxic compounds was further strengthened: eicosane became the most toxic substance (LC₉₀ = 0.016 mg/L), followed by tetradecane and hexadecane (both 0.128 mg/L), and decane (0.133 mg/L). Only tridecane maintained an extremely low toxicity level with an LC₉₀ of 10,155.754 mg/L. Overall, hexadecane, decane, tetradecane, and eicosane were consistently highly toxic compounds at all tested durations, whereas nonadecane, heneicosane, and tridecane consistently showed low toxicity. Furthermore, the lethal concentration thresholds of highly toxic compounds continuously decreased with prolonged fumigation time, demonstrating a clear time-toxicity cumulative effect. Table 8 LC50 values of different compounds for fumigating S. invicta at the 12th Substance Slope ± SE LC50(mg/L) 95% CI Undecane 0.26 ± 0.10 277.83 36.14-3358372201.45 Tridecane 0.38 ± 0.10 16.81 8.36-109.98 Pentadecane 0.48 ± 0.10 2.22 1.31–3.31 Heptadecane 0.63 ± 0.10 7.03 5.03–11.66 Decane 0.21 ± 0.10 0.01 0-0.16 Tetradecane 0.21 ± 0.10 0.08 0-0.52 Hexadecane 0.21 ± 0.11 0.00 Cetene 0.24 ± 0.10 2.45 0.34–6.76 Eicosane 0.51 ± 0.10 0.52 0.15–0.94 Nonadecane 0.18 ± 0.10 6966.67 Heneicosane 0.04 ± 0.10 5620049434643.50 13-Docosenamide 0.20 ± 0.10 72.40 13.11-2.649E + 168 Table 9 LC90 values of different compounds for fumigating S. invicta at the 24th Substance Slope ± SE LC90(mg/L) 95% CI Undecane 0.36 ± 0.13 5.043 2.55–33.56 Tridecane 0.18 ± 0.11 10155.754 Pentadecane 0.69 ± 0.19 0.654 0.15–1.17 Heptadecane 0.99 ± 0.17 1.769 1.28–2.38 Decane 1.10 ± 0.56 0.133 Tetradecane 0.75 ± 0.32 0.128 0-0.47 Hexadecane 0.75 ± 0.32 0.128 0-0.47 Cetene 0.65 ± 0.20 0.383 0.02–0.85 Eicosane 0.34 ± 0.23 0.016 Nonadecane 0.43 ± 0.12 10.025 5.22–63.28 Heneicosane 0.31 ± 0.14 2.981 1.01–11.85 13-Docosenamide 0.89 ± 0.22 0.562 0.16–0.95 Table 10 KT50 values of different compounds at a concentration of 0.78mg/L Substance Slope ± SE KT50(h) 95% CI Undecane 2.83 ± 0.48 33.68 22.97–70.37 Tridecane 3.77 ± 0.50 21.00 16.94–29.83 Pentadecane 4.58 ± 0.51 15.55 13.63–18.84 Heptadecane 4.32 ± 0.58 20.62 16.84–28.75 Decane 6.97 ± 0.59 10.99 9.47–14.35 Tetradecane 6.32 ± 0.53 10.97 10.30-11.85 Hexadecane 4.98 ± 0.39 9.05 7.15–13.26 Cetene 7.59 ± 0.77 13.22 12.27–14.65 Eicosane 6.81 ± 0.61 11.73 10.99–12.74 Nonadecane 6.58 ± 0.96 18.80 15.94-25.00 Heneicosane 8.00 ± 0.96 14.98 13.60-17.34 13-Docosenamide 10.06 ± 1.14 13.73 12.80–15.20 At a fixed concentration of 0.78 mg/L, the results of KT50 (median knockdown time) obtained based on Logit model fitting showed that there were significant differences in the speed of knockdown of S. invicta by the tested compounds. Hexadecane had the fastest knockdown speed, with a KT50 of only 9.05 h (95% confidence interval: 7.15–13.26 h), and the dose-effect relationship was robust (slope = 4.98 ± 0.39). Decane (10.99 h), tetradecane (10.97 h), and eicosane (11.73 h) also exhibited relatively fast knockdown activity, with KT50 values all within 12 h. The knockdown speeds of hexadecene (13.22 h), erucamide (13.73 h), heneicosane (14.98 h), and pentadecane (15.55 h) were next, with KT50 values ranging from 13 to 16 h. Heptadecane (20.62 h), tridecane (21.00 h), nonadecane (18.80 h), and undecane (33.68 h) had slower knockdown speeds. Among them, undecane had the highest KT50 and the slowest knockdown effect. Overall, hexadecane was the compound with the fastest speed in knocking down S. invicta , while undecane had the slowest knockdown speed. The difference in KT50 among the tested compounds exceeded 3 times, reflecting significant differences in knockdown activity. 2.6 Comprehensive analysis of toxicity of different compounds by topical application on S. invicta The acute lethal effects of the tested compounds on S. invicta were further investigated via topical application bioassays, with LD₅₀ (24 h) and LD₉₀ (48 h) calculated using the Probit model. The results demonstrated significant differences in acute toxicity among compounds, and the lethal dose thresholds of highly toxic compounds continued to decrease with prolonged observation time, confirming the time-dependent toxicity enhancement (Tables 11 and 12). Table 11 LD50 values of different compounds against S. invicta at 24 hours using the Topical application Substance Slope ± SE LD50(ng/ant) 95% CI Undecane 0.76 ± 0.12 8.02 3.76-239.38 Tridecane 0.28 ± 0.12 94.99 18.68-209608217.96 Pentadecane 0.20 ± 0.12 5307.35 Heptadecane 0.34 ± 0.12 0.58 0.02–1.35 Decane 0.35 ± 0.11 5.88 3.15–26.17 Tetradecane 0.20 ± 0.12 783.96 Hexadecane 0.38 ± 0.13 0.01 0-0.13 Cetene 0.43 ± 0.12 17.68 8.49-144.91 Eicosane 0.50 ± 0.13 88.03 28.14-2266.20 Nonadecane 0.49 ± 0.16 0.01 0-0.07 Heneicosane 0.49 ± 0.16 18.58 10.09–70.60 13-Docosenamide 0.28 ± 0.11 2.99 0.74–10.21 In the 24 h topical LD₅₀ assay, hexadecane and nonadecane displayed extremely strong acute toxicity, both with an LD₅₀ of 0.01 ng/ant. Hexadecane showed a robust dose–response relationship (slope = 0.38 ± 0.13) with a 95% confidence interval (CI) of 0–0.13 ng/ant. Heptadecane was the next most toxic compound, with an LD₅₀ of 0.58 ng/ant (95% CI: 0.02–1.35 ng/ant). Erucamide (2.99 ng/ant, 95% CI: 0.74–10.21 ng/ant), decane (5.88 ng/ant, 95% CI: 3.15–26.17 ng/ant), and undecane (8.02 ng/ant, 95% CI: 3.76–239.38 ng/ant) also exhibited relatively high acute toxicity. In comparison, hexadecene (17.68 ng/ant), heneicosane (18.58 ng/ant), eicosane (88.03 ng/ant), and tridecane (94.99 ng/ant) showed moderate toxicity. Tetradecane (783.96 ng/ant) and pentadecane (5307.35 ng/ant) had extremely high LD₅₀ values, indicating extremely weak acute toxicity. Notably, some compounds showed extremely wide or missing 95% CIs, suggesting poor stability in their dose–response relationships. In the 48 h topical LD₉₀ assay, the lethal activity of highly toxic compounds was further enhanced. Hexadecane remained the most toxic compound with an LD₉₀ of only 0.02 ng/ant (slope = 0.67 ± 0.57). Decane (0.11 ng/ant), nonadecane (0.38 ng/ant, 95% CI: 0.02–0.73 ng/ant), hexadecene (0.52 ng/ant, 95% CI: 0.07–0.99 ng/ant), and tetradecane (0.91 ng/ant, 95% CI: 0.17–1.66 ng/ant) also displayed extremely high lethal activity, with all LD₉₀ values below 1 ng/ant. Heptadecane had an LD₉₀ of 0 ng/ant, indicating that a 90% lethal effect could be achieved at an extremely low dose. Undecane (1.34 ng/ant, 95% CI: 0.00–3.42 ng/ant) showed moderate toxicity. In contrast, tridecane (11.58 ng/ant), erucamide (28.64 ng/ant), heneicosane (30.98 ng/ant), eicosane (57.83 ng/ant), and pentadecane (65.72 ng/ant) had significantly higher LD₉₀ values, reflecting weak lethal activity. Table 12 LD50 values of different compounds against S. invicta at 48 hours using the Topical application Substance Slope ± SE LD90(ng/ant) 95% CI Undecane 0.35 ± 0.17 1.34 0.00-3.42 Tridecane 0.49 ± 0.14 11.58 5.81–85.85 Pentadecane 0.40 ± 0.13 65.72 17.82-14769.20 Heptadecane 0.25 ± 0.34 0 Decane 0.49 ± 0.26 0.11 Tetradecane 0.62 ± 0.20 0.91 0.17–1.66 Hexadecane 0.67 ± 0.57 0.02 Cetene 0.84 ± 0.26 0.52 0.07–0.99 Eicosane 0.57 ± 0.28 57.83 22.17–556.70 Nonadecane 1.22 ± 0.42 0.38 0.02–0.73 Heneicosane 0.56 ± 0.13 30.98 13.58-229.41 13-Docosenamide 0.47 ± 0.13 28.64 11.33-507.49 Conclusion and discussion In this study, mock competition experiments involving S. invicta and eight other ant species were conducted. In individual attack experiments, the proportion of low-level attacks (Grades I and II) by T. melanocephalum was the highest, while the total number of attacks and the number of level IV attacks were the lowest. This indicates that T. melanocephalum mostly stays in a evasive state during individual competition and will not take the initiative to attack S. invicta . The results of competition experiments between T. melanocephalum and S. invicta revealed that T. melanocephalum also stayed away from S. invicta , thus avoiding attack (Huang 2016 ). The proportion of the level IV attacks by O. smaragdina and O. smaragdina is relatively high among large other ants, and their attack indices are also relatively large. This indicates that these two species of ants will choose to actively attack when facing S. invicta , and can kill S. invicta in a short period of time. C. pseudoirritans would stand still in the early stage of competition with S. invicta until the S. invicta individual touched it; otherwise, the two ants would not attack each other. C. pseudoirritans has the habit of feigning death; therefore, it is speculated that they use this method to evade attacks when encountering large S. invicta . Therefore, the attack index of the proposed C. pseudoirritans and the proportion of attacks at Grades III and IV were also relatively small. In group competition, the mortality rate of S. invicta . caused by T. melanocephalum is the lowest. Under the proportional ratios of 5:1, 3:1, and 3:2 (i.e., when the number of T. melanocephalum is larger), their own mortality rate is higher. When the number of T. melanocephalum decreases, their own mortality rate reduces. This may be because T. melanocephalum has a small size and a relatively fast movement speed, making them difficult to catch. Although the attack index of P. megacephala is significantly higher than that of A. gracilipes and T. melanocephalum , their own mortality rate is the highest in group competition, indicating that P. megacephala has no advantage in competition with S. invicta . In the 1:1 colony attack experiment, three biological control species ( P. dives , O. smaragdina and C. japonicus ) and two native species ( C. nicobarensis and C. pseudoirritans ) indeed inhibited the invasion of S. invicta . Moreover, the mortality rate of S. invicta caused by C. japonicus was over 95% under all seven proportion conditions, indicating that C. japonicus has strong attack power. Interspecific competition is the main process involved in the construction of ecological communities. Under the influence of phenotypic differences among species, the limited similarity theory suggests that species with similar shapes could strongly replace other species, and that the final result is competitive replacement. Biological invasion often leads to strong competitive interactions, and is a suitable model for investigating competition (Shea et al. 2002; Dunham and Mikheyev 2010 ). For example, before the arrival of S. invicta , Solenopsis geminata and Solenopsis xyloni MacCook were the dominant species in their corresponding regions (Porter and Savignano 1990 ), but when S. invicta invaded, the tropical fire ant was the first to be replaced. There are reported a clear competitive relationship between S. invicta and Camponotus lensus and Camponotus dolendus through interference and resource predation competition (Xi et al. 2007 ). Recent research suggests that the coexistence mechanism between indigenous ants and invasive S. invicta involves behavioral plasticity (Tschinkel 2006 ), resource utilization differentiation (Lebrun et al. 2012 ), and competition defense trade-offs (Stuble et al. 2009 ), rather than simply a balance of offensive and defensive abilities. The native ant species that coexist with S. invicta have varying degrees of control over S. invicta (Allen et al. 1994 ), and this control comes mainly from interspecific competition. In its native area in Brazil, the proportion of S. invicta (which represents the population density to a certain extent) is lower than that in the United States (Porter et al. 1992 ). There are studied the competitiveness of T. melanocephalum and Pheidole fervida Smith against S. invicta , and reported that the attack intensity between T. melanocephalum and S. invicta was relatively weak, whereas Pheidole fervida Smith and S. invicta attacked each other intensely, resulting in increased mortality (Gao et al. 2011 ). Therefore, many scholars believe that this competition may be a factor controlling the invasiveness of S. invicta . These studies indicate that interactions between S. invicta and other ants limit S. invicta (Tschinkel 2006 ; Stimac and Alves 1994 ). Quantitative advantage is also critical in interspecific competition among ants (Holway et al. 2002 ). As the number of P. dives and A. gracilipes increases, their lethality rate against S. invicta also rises, indicating that when these two species of ants are present in sufficient numbers, they also can completely resist attacks by S. invicta , and thus has a strong competitive advantage. However, at ratios of 1:3 and 1:5, when S. invicta had a numerical advantage, A. gracilipes was at a disadvantage, even with its defensive secretions. Although the mortality rate of T. melanocephalum and P. megacephala against S. invicta is very low, when the ratio is 5:1, their mortality rate against S. invicta reaches the highest value among all ratios. At the end of the experiment, many broken legs or abdomens of S. invicta were observed in the boxes containing O. smaragdina , C. japonicus , C. nicobarensis and C. pseudoirritans , indicating that these four types of ants have a powerful mandible and strong biting ability. These ants not only use their strong mandibles to attack S. invicta but also secrete substances to defend themselves against S. invicta . During the experiment, a pungent odor was often detected around the small box, indicating that ants not only use their mandibles to fight S. invicta , but also attack S. invicta by secreting venom from the abdomen. The venom can cause the ant’s feet to stick and the body to twitch, and the ant slowly curls up until it dies. Phylogenetic studies have shown that Formicinae have undergone a reduction in venom gland development during their evolutionary history, leading to an adaptive trait of spraying formic acid and other defensive secretions through specialized acidpores (Touchard et al. 2016 ). Therefore, when nail polish is used to block the end of the abdomen acidpore of an ant to prevent the secretion of venom, the mortality of S. invicta differs considerably during colony attack. In addition, nail polish itself does not threaten ant ant mortality. In addition, in Experiment 1.3 (i), applying nail polish to the abdomen of S. invicta did not cause their death within 2 hours, and the survival rate was 100% (Lebrun EG et al. 2014 ). So in the experiments in which the nail polish was used to seal the acidopore, the mortality of S. invicta caused by O. smaragdina , C. japonicus , C. nicobarensis and A. gracilipes was significantly lower than that when the orifice was not sealed. What are these secretions? The results of this experiment revealed that the types of compounds within ant secretions included alkanes, acids, benzene, alkenes, and a small amount of other substances; the content of alkanes was the highest, and undecane and tridecane were present in all six ant species. Two types of glands in ants, namely the venom glands and the Dufour glands (Gullan and Cranston 2014 ), secrete, store, and excretory chemical substances. The main function of the venom glands is to produce defensive venom (Shang 2006 ), and the excretion of toxins through venom glands is part of a relatively complex mechanism for prey capture and defense (Lima et al. 2018 ). The secretions of the Dufour glands contain linear alkanes and small amounts of alkenes and alkynes. These substances have various functions, the most primitive of which are related to female reproduction. Undecane, tridecane, decyl acetate, and dodecyl acetate secreted by the Dufour glands also have defensive functions. There are analyzed the substances from the Dufour glands and venom glands of Nylanderia fulva and revealed that the main substances were formic acid, undecane and 2-tridecanone; both undecane and 2-tridecanone had some contact toxicity against S. invicta (Chen et al. 2013 ). Formic acid is widely present in ants, such as Formica rufa Linnaeus, and is a key defensive secretion (Morgan 2008 ), and it is worth considering for the prevention and control of S. invicta (Chen et al. 2012 ). The results of this study show that in the fumigation test, hexadecane had the lowest LC value and KT50; in the topical application, nonadecane and hexadecane had the lowest LD values. This indicates that these two compounds have the strongest toxicity to S. invicta . Among them, hexadecane was detected only in O. smaragdina , whereas nonadecane was detected in all other species except C. japonicus and P. dives . In this study, C. japonicus presented a significant advantage in terms of group competition and had the highest mortality rate against S. invicta . However, substances with relatively high contents in the secretions were not significantly toxic to S. invicta . In the nail polish experiment, there was no significant difference in the self-mortality rate of C. japonicus with nail polish on the abdomen, indicating that C. japonicus mainly rely on the tearing and bite ability of the upper jaw to compete with S. invicta and have strong fighting ability. But it is possible that toxic substances in the secretions of C. japonicus are present at extremely low levels, requiring further screening and testing of the identified substances. Alkanes, such as nonadecane and hexadecane, have been studied only for their important roles in aggregation and individual communication. For example, bark beetles largely use volatile n-alkanes from the host to search for and identify hosts and for interspecific chemical communication (Fan et al. 2015 ). Although there are few studies on their toxic effects, alkanes may be diffusion agents for formic acid or alkaloids; however, this has not been confirmed (Chen et al. 2013 ), in the future, the two glands will be extracted separately and further studied. In summary, S. invicta is characterized by strong interspecific aggressiveness, high biological activity, and large colonies. This species often changes the composition of the ecological community in invaded areas and often eliminates native ants from competition. The current study revealed that the competition between individual worker ants includes physical and chemical attacks. Physical attacks depend on the size and agility of worker ants. For example, there are reported that T. melanocephalum , in a one-on-one interaction with a competitor, uses physical attacks and chemical defense substances simultaneously (Li et al. 2008 ). In this article, the mortality rate of T. melanocephalum in competition with S. invicta is indeed low. There may be some substances that keep S. invicta away from them, but these substances do not cause the death of S. invicta . Therefore, the secretions of T. melanocephalum were not extracted in this article, and further research can be conducted later. The experimental results revealed that S. invicta has a definite advantage in terms of interspecific competition with smaller ants. However, when S. invicta encounters larger ants or those that can secrete defensive chemical substances, increasing the number of S. invicta will also increase the mortality rate of local ants. This experiment further demonstrated the threat of S. invicta invasion of native ants and its impact on the ecosystem. However, these findings also revealed that native ants have an inhibitory effect on S. invicta invasion (Vogt et al. 2005 ). The use of chemical agents is effective for the control of S. invicta (Drees et al. 2013 ), but improper treatment not only pollutes the environment and causes a certain degree of nest migration, but also leads to a decrease in the number of native ants, resulting in a relatively high invasion density of S. invicta (Morehart et al. 2022 ; Holmes et al. 2013). Therefore, when integrated control strategies for S. invicta in different habitats are considered, the defense ability of local ants can be used to strengthen the control of S. invicta . Declarations Acknowledgments This research was funded by the Science & Technology Planning Project of Guangdong (2024B1212050005) and Shenzhen Wild Animal and Plant Protection Administration Division. Conflict of interest declaration The authors declare no conflicts of interest associated with this work. 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Ecological Entomology 34(4): 520–526. http://doi.org/10.1111/j.1365-2311.2009.01098.x Suarez AV, Holway DA, Liang D, Tsutsui ND and Case TJ (2002) Spatiotemporal patterns of intraspecific aggression in the invasive argentine ant. Animal Behaviour 64(5):697–708. http://doi.org/10.1006/anbe.2002.4011 Touchard A, Aili SR, Fox EGP, Escoubas P, Orivel J, Nicholson GM and Dejean A (2016) The biochemical toxin arsenal from ant venoms. Toxins 8(1): 30. http://doi.org/10.3390/toxins8010030 Tschinkel WR (2006) The fire ants. Cambridge, MA, USA:The Belknap Press of Harvard University Press. https://api.semanticscholar.org/CorpusID:82739243 . http://doi.org/10.5860/choice.38-4452 Vogt JT, Reed JT, Brown RL (2005) Timing bait applications for control of imported fire ants (hymenoptera: formicidae) in mississippi: efficacy and effects on non-target ants. International Journal of Pest Management 51(02):121–130. http://doi.org/10.1080/09670870500097478 Wanandy T, Mulcahy E, Lau WY, Brown SGA and Wiese MD (2022) Global view on ant venom allergy: From allergenic components to clinical management. Clinical Reviews in Allergy&Immunology 62(1): 123–144. https://doi.org/10.1007/s12016-021-08858-1 Wang C, Zhu T, Yang X, Liang X, Wang L, Lu Y, Wen X, Hua Y (2024) Advances in red imported fire ant impacts on vertebrates. Acta Ecologica Sinica 44 (9): 3575–3585. http://doi.org/10.20103/j.stxb.202211163313 Wang L, Wang Z, Zeng L, Lu Y (2017) Negative effects of red imported fire ant ( Solenopsis invicta Buren ) invasion on arthropod community in the banana plantations. Journal of Environmental Entomology 39(04):835–847 Wu B, Lu Y, Liang G and Zeng L (2010) Influence of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formiciddae) on the diversity of ant communities in a newly infested longan orchard and grass areas nearby. Shengtai Xuebao/ Acta Ecologica Sinica 30:2075–2083. http://doi.org/10.20103/j.stxb.2010.08.015 Wylie FR and Janssen-May S (2017) Red imported fire ant in Australia: What if we lose the war? Ecological Management & Restoration 18 (1): 32–44. http://doi.org/10.1111/emr.12238 Xi Y, Lu Y, Liang G, Zeng L and Xu Y (2010) Effects of the red imported fire ant (RIFA), Solenopsis invicta Buren,on diversity and stability of invertebrate community in litchi orchards. Acta Ecologica Sinica 30(08): 2084–2099. http://doi.org/10.20103/j.stxb.2010.08.016 Xi Y, Zeng L, Lu Y, Xu Y, Liang G, Zhang W (2007) Interspecific Relationship Between Solenopsis invicta and Camponotus dolendus in Litchi Orchard. Journal of South China Agricultural University 28(4):6–10 Zhao S, Jia F, Liang G, Ke Y and Tian W (2009) Ant species and their distribution in Guangdong Province. Journal of Environmental Entomology 31(2):156–161 Table 4 To 6 Table 4 To 6 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Table4To6.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9183057","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":614125496,"identity":"cc0e12e2-bdbc-4242-a131-e6c1f30717ed","order_by":0,"name":"Wenqiu Zhang","email":"","orcid":"","institution":"Institute of Zoology, Guangdong Academy of Sciences","correspondingAuthor":false,"prefix":"","firstName":"Wenqiu","middleName":"","lastName":"Zhang","suffix":""},{"id":614125497,"identity":"711e0613-5872-4ef9-b481-04c81491de7a","order_by":1,"name":"Lu Jiang","email":"","orcid":"","institution":"Shenzhen Wild Animal and Plant Protection Administration Division","correspondingAuthor":false,"prefix":"","firstName":"Lu","middleName":"","lastName":"Jiang","suffix":""},{"id":614125498,"identity":"5b98e346-2945-48b0-a5ad-b4947da59b33","order_by":2,"name":"Mianchang Cheng","email":"","orcid":"","institution":"Guangzhou Cigarette Factory","correspondingAuthor":false,"prefix":"","firstName":"Mianchang","middleName":"","lastName":"Cheng","suffix":""},{"id":614125499,"identity":"9b9f0850-8768-4119-bde0-394b3563dba8","order_by":3,"name":"Yijuan Xu","email":"","orcid":"","institution":"South China Agricultural University","correspondingAuthor":false,"prefix":"","firstName":"Yijuan","middleName":"","lastName":"Xu","suffix":""},{"id":614125500,"identity":"b6fda58c-d124-43bc-909d-d21b27b8d48b","order_by":4,"name":"Jun Li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAvklEQVRIiWNgGAWjYBACxgYGxgMfGCQYDEA8HiK1MBycQZIWEDgMUkm8FuYZuQcO2/yykDeXPsD84g2DXR5hh83ISzic2ydhuLMvgc1yDkNyMRFacgwO5/ZIMG44w8BmzMNwILGBKC2WPRL2JGph+CGRCNTC/Jg4LT1vDA72Nkgk7+xhbGOcY5BMWIthe47hgx9/6my38zAf/vCmwo4ILSAVjG1gC9ugEUoAyIPJP2CS+QMRGkbBKBgFo2AEAgDgnz5RP4dfqwAAAABJRU5ErkJggg==","orcid":"","institution":"Institute of Zoology, Guangdong Academy of Sciences","correspondingAuthor":true,"prefix":"","firstName":"Jun","middleName":"","lastName":"Li","suffix":""}],"badges":[],"createdAt":"2026-03-21 04:23:16","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9183057/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9183057/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106027223,"identity":"0489c0a4-47b3-4ed9-8c2c-c38438b9c2b6","added_by":"auto","created_at":"2026-04-02 14:49:54","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":52981,"visible":true,"origin":"","legend":"\u003cp\u003eIndividual attack test\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-9183057/v1/6dfee95f5ae42fe3fc54505d.png"},{"id":106093864,"identity":"b2b8cf41-1c86-4870-91fc-570640f80d06","added_by":"auto","created_at":"2026-04-03 11:39:38","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":77763,"visible":true,"origin":"","legend":"\u003cp\u003eColony attack test\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-9183057/v1/8cedfe9ca5dd9cce221d517b.png"},{"id":106094290,"identity":"c3508266-ce23-41aa-b40e-e228bed0ff88","added_by":"auto","created_at":"2026-04-03 11:42:03","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":253372,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u0026nbsp;\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-9183057/v1/9884647c0649333436839311.png"},{"id":106094332,"identity":"accc07d9-3666-4eb6-b5ab-718e619431ef","added_by":"auto","created_at":"2026-04-03 11:42:12","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":527439,"visible":true,"origin":"","legend":"\u003cp\u003eMortality of \u003cem\u003eS. invicta\u003c/em\u003e in different combination ratios. The Kruskal-Wallis H test and Kruskal-Wallis single-factor analysis with multiple comparisons were used for each data point. Data with different letters are significantly different at the level of 0.05. The same is true for Fig. 5.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-9183057/v1/6947751e855429469dea9886.png"},{"id":106027227,"identity":"7b787807-fdca-41a9-9bd7-39dd716a8d0f","added_by":"auto","created_at":"2026-04-02 14:49:54","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":471725,"visible":true,"origin":"","legend":"\u003cp\u003eMortality of other ants in different combination ratios\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-9183057/v1/8269ef9a87c2a27eb5a4c441.png"},{"id":107648821,"identity":"f0ba071b-0830-4a10-a4e3-836e750115fa","added_by":"auto","created_at":"2026-04-23 14:41:30","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2162995,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9183057/v1/9323129b-0187-429b-bce5-3914d5b312a4.pdf"},{"id":106094764,"identity":"a2950789-12e9-4c23-9b48-84b5471d3749","added_by":"auto","created_at":"2026-04-03 11:43:13","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":20004,"visible":true,"origin":"","legend":"","description":"","filename":"Table4To6.docx","url":"https://assets-eu.researchsquare.com/files/rs-9183057/v1/c6cf3a680dd198ad6ce70fc9.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Interspecific competition between Solenopsis invicta Buren and eight other ant species","fulltext":[{"header":"Introduction","content":"\u003cp\u003e \u003cem\u003eSolenopsis invicta\u003c/em\u003e is an important invasive ant species that not only adversely affects agricultural production, public facilities, and public health but also causes considerable damage to the ecological environment in invaded areas (Nattrass and Vanderwoude \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Wanandy et al. \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Invasion by \u003cem\u003eSolenopsis invicta\u003c/em\u003e has a severe negative effect on the species diversity and richness of local arthropods, such as spiders and ants, and can reduce the species richness of native ants by more than 33% (Jiang et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Song et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Wu et al. \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Lu et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Huang et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Qi et al. \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Wylie and Janssen-May \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Wang et al. \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Additionally, \u003cem\u003eS. invicta\u003c/em\u003e can change the foraging and attack behavior of some native ants and has significant negative effects on the characteristics and structure of the arthropod community in banana plantations and lychee orchards (Huang \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Cheng et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Xi et al. \u003cspan citationid=\"CR54\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Wang et al. \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eInterspecific competition often occurs in nature. Severe interspecific competition leads to competitive displacement, leading not only to the replacement of rivals but also to a decrease in species diversity, thereby affecting the entire ecosystem (Cardinale et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Gao and Reitz \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Goodsman et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Cui et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Dang et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Invasive ants compete with native ants with similar ecological niches for food resources and territories (Buczkowski and Bennett \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). The destruction of indigenous ant colonies due to invasion and colonization by \u003cem\u003eS. invicta\u003c/em\u003e has become an ecological issue that has attracted considerable attention. Several studies have shown that \u003cem\u003eS. invicta\u003c/em\u003e coexists with a variety of other native ants; furthermore, native ants that coexist with \u003cem\u003eS. invicta\u003c/em\u003e have strong competitive abilities and can resist competition by invasive ants. The coexistence mechanism between \u003cem\u003eMonomorium minimum\u003c/em\u003e and \u003cem\u003eS. invicta\u003c/em\u003e in the southeastern United States involves differences in heat tolerance (Adams and Traniello \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1981\u003c/span\u003e; Bujan et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), allowing them to occupy different ecological niches in high-temperature environments. There are studied the competition between \u003cem\u003eP. dives\u003c/em\u003e and \u003cem\u003eS. invicta\u003c/em\u003e and reported that \u003cem\u003eP. dives\u003c/em\u003e strongly attacked \u003cem\u003eS. invicta\u003c/em\u003e and that \u003cem\u003eP. dives\u003c/em\u003e inhibited the expansion of \u003cem\u003eS. invicta\u003c/em\u003e to a certain extent (Li and Yang \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). On the basis of the literature, eight different ant species (\u003cem\u003eOecophylla smaragdin\u003c/em\u003e, \u003cem\u003ePolyrhachis dives\u003c/em\u003e, \u003cem\u003eCamponotus japonicus\u003c/em\u003e, \u003cem\u003eAnoplolepis gracilipes\u003c/em\u003e, \u003cem\u003eCamponotus nicobarensis\u003c/em\u003e and \u003cem\u003eCamponotus pseudoirritans\u003c/em\u003e, \u003cem\u003eTapinoma melanocephalum and Pheidole megacephala\u003c/em\u003e) that are widely distributed in Guangzhou, they were selected to study their interspecific competition with S. invicta (Zhao 2009; Ran \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2011\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2012\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). The difference in mortality between these species and \u003cem\u003eS. invicta\u003c/em\u003e during competition was analyzed, and the acidopore were sealed to determine the auxiliary effect of venom on attack by the test ants on \u003cem\u003eS. invicta\u003c/em\u003e, thus revealing the importance of chemical attack in the competition between local ants and \u003cem\u003eS. invicta\u003c/em\u003e. When an integrated control strategy for \u003cem\u003eS. invicta\u003c/em\u003e in different habitats is considered, the number of local ants and other native species can be increased, the population number of \u003cem\u003eS. invicta\u003c/em\u003e in the invaded area can be reduced through competition and confrontation, and the resistance effect of local ants can be fully exerted. The chemical substances secreted by local ants that compete with \u003cem\u003eS. invicta\u003c/em\u003e were analyzed to reveal the function and efficacy of the secretions in the competition and confrontation processes, provide a theoretical basis for the development of new bioderived agents, and provide guidance for new approaches to control \u003cem\u003eS. invicta\u003c/em\u003e.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e1.1 Insects\u003c/h2\u003e \u003cp\u003eTen \u003cem\u003eS. invicta\u003c/em\u003e colonies were collected from Gangwei Village, Baiyun District, Guangzhou City (113\u0026deg;23'E, 23\u0026deg;22'N). The collected \u003cem\u003eS. invicta\u003c/em\u003e colonies were placed into plastic buckets coated with talcum powder for 2\u0026ndash;3 days until they nested stably in the buckets. The dripping method was used to extract the ant colonies from the soil (Chen \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Water was slowly dripped into the buckets with constant observation of the water level. The ants moved to the top of the soil and floated or formed a \u0026ldquo;raft\u0026rdquo; on the surface of the water. The ants were scooped out and placed in plastic boxes (340 mm\u0026times;270 mm\u0026times;130 mm), wherein the inner walls of the boxes were coated with talcum powder and reared on ham sausage and 10% sugar water for seven days. The room temperature ranged from 23 to 28\u0026deg;C, and the humidity ranged from 60 to 70%.\u003c/p\u003e \u003cp\u003eThe remaining ants were collected from other areas of Guangdong Province. Three \u003cem\u003eO. smaragdina\u003c/em\u003e colonies were collected from Hetian Town, Luhe County, Shanwei City (115\u0026deg;39\u0026prime;E, 23\u0026deg;18\u0026prime;N). Three \u003cem\u003eP. dive\u003c/em\u003e colonies were collected from Chengxi Village, Enping District, Jiangmen City (112\u0026deg;17\u0026prime;E, 22\u0026deg;10\u0026prime;N). Three \u003cem\u003eC. japonicus\u003c/em\u003e colonies were collected from Ruyuan County, Shaoguan City (113\u0026deg;16\u0026prime;E, 24\u0026deg;46\u0026prime;N). Three \u003cem\u003eC. nicobarensis\u003c/em\u003e colonies were collected from Yunfu City, Guangdong Province (112\u0026deg;02\u0026prime;E, 22\u0026deg;55\u0026prime;N), China. Three \u003cem\u003eC. pseudoirritans\u003c/em\u003e colonies were collected from Heyuan City, Guangdong Province (114\u0026deg;41\u0026prime;E, 23\u0026deg;44\u0026prime;N). Three \u003cem\u003eA. gracilipes\u003c/em\u003e colonies were collected from Dapeng New District, Shenzhen City, Guangdong Province (114\u0026deg;28\u0026prime;E, 22\u0026deg;35\u0026prime;N). Three \u003cem\u003eT. melanocephalum and P. megacephala\u003c/em\u003e colonies were collected from Xihutang Village, Baiyun District, Guangzhou City (113\u0026deg;23\u0026prime;E, 23\u0026deg;19\u0026prime;N). The collected ant nests were placed in plastic boxes coated with talcum powder and fed 20% sugar water daily. The room temperature was 25\u0026thinsp;\u0026plusmn;\u0026thinsp;2\u0026deg;C and the humidity was 80\u0026thinsp;\u0026plusmn;\u0026thinsp;5%. And there are quarantine measures and anti-escape measures in the laboratory.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e1.2 Competition evaluation\u003c/h2\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e1.2.1 Individual attack tests\u003c/h2\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA transparent container with a diameter of 15 mm and a length of 15 mm was placed on white paper. This container was used to observe the aggressive behavior of the ants. During the test, two ants of different species were placed in an observation container with soft tweezers, and the aggressive behavior of the ants was observed at close range with the naked eye (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). According to the literature review, attack intensity was divided into the following four levels: Grade I, Grade II, Grade III, Grade IV, detailed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e (Suarez et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Grangier et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Small (head width\u0026thinsp;\u0026lt;\u0026thinsp;1.0 mm), medium (head width\u0026thinsp;=\u0026thinsp;1.0\u0026thinsp;~\u0026thinsp;1.35 mm), and large (head width\u0026thinsp;\u0026gt;\u0026thinsp;1.35 mm) \u003cem\u003eS. invicta\u003c/em\u003e worker ants were paired with other ants at a ratio of 1:1 for a total of three treatments, each group was repeated in three ant nests, with each ant nest repeated 10 times, totaling 30 repetitions per group. Additionally, each group was observed for 5 minutes consecutively.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eIndividual Attack Level Classification Table\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c4\" namest=\"c1\"\u003e \u003cp\u003eLevel\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eII\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eIII\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eIV\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eshort-term antennal contact (\u0026lt;\u0026thinsp;1 s)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003elong-term antennal contact (\u0026ge;\u0026thinsp;1 s)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eone party tilted its abdomen up, opened the mandible in a threatening posture, or quickly climbed to the other party\u0026rsquo;s back\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003etwo parties attacked and became entangled with each other, or one party violently attacked the other party with its mandible or stinger\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e1.2.2 Group attack tests\u003c/h2\u003e \u003cp\u003eThe ratios of \u003cem\u003eS. invicta\u003c/em\u003e to other ants used were 5:1, 3:1, 3:2, 1:1, 2:3, 1:3, and 1:5 (the number of \u003cem\u003eS. invicta\u003c/em\u003e was always 15). The ants were placed in a box using soft tweezers. After 1 min of adaptation, \u003cem\u003eS. invicta\u003c/em\u003e were placed in a small box (Fig.\u0026nbsp;2). Observed the death of two test ants within 30min, judged the dead or unable to stand ants within 1 hour as dead individuals, and recorded the number of deaths of \u003cem\u003eS. invicta\u003c/em\u003e and other ants respectively, and the test was repeated 15 times independently for each group, each type of ant repeated three nests.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e1.3 Sealing the acidopore\u003c/h2\u003e \u003cp\u003eAfter the test described in Section \u003cspan refid=\"Sec4\" class=\"InternalRef\"\u003e1.2\u003c/span\u003e, the ends of the abdomens of the tested ants were sealed with nail polish (Orange, white) (Lebrun et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2014\u003c/span\u003e), and the glands of the other parts were not sealed. This sealing prevented the ants from secreting venom, thus revealing the importance of chemical attack by the test ants when fighting \u003cem\u003eS. invicta\u003c/em\u003e, and clarifying the function of the test ant venom in attack behavior. The setting experiment is as follows: (i), take 10 heads of the other six kinds of ants, applied nail polish on their abdomens, and leaved them for 2 hours without putting \u003cem\u003eS. invicta\u003c/em\u003e to find out whether the nail polish is harmful to ants; (ii)The acidpore at the end of the abdomen of other ants were blocked with nail polish, and a competition control was set up with \u003cem\u003eS. invicta\u003c/em\u003e at a ratio of 1:5, using the method described in 1.2.2 (iii) A false blockage was created by applying a dot of nail polish on the side of the abdomen, and a competition control was set up with red imported fire ants at a ratio of 1:5, using the same method as above.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e1.4 Analysis of glandular compounds\u003c/h2\u003e \u003cdiv id=\"Sec9\" class=\"Section3\"\u003e \u003ch2\u003e1.4.1 Extraction of ant glands\u003c/h2\u003e \u003cp\u003eTwenty ants of each of the six species were selected and placed in a foam box filled with ice cubes for sacrifice. The venom and Dufour glands were subsequently extracted under a dissecting microscope. The glands were placed into a 4-mL glass vial containing n-hexane (0.5 mL) and soaked with a glass rod at room temperature for 10 min. Then, the extract was filtered into a clean 4-mL vial via a glass pipette. Each type of ant was tested three times.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e1.4.2 GC‒MS conditions\u003c/h2\u003e \u003cp\u003eThe instrument used was an Agilent GC-MS (7890 B, G3440B, 2017) with an HP-5 column. The temperature program was as follows: 50\u0026deg;C for 5 min, increased in 10\u0026deg;C increments until it reached 280\u0026deg;C, and maintained for 10 min. The injector port, ion trap, and transfer line temperatures were set to 250, 200, and 280\u0026deg;C, respectively.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e1.5 Toxicity test for each reagent\u003c/h2\u003e \u003cp\u003eAccording to the analysis of GC-MS results, the purchased standard samples of the major compounds were used to perform contact toxicity and fumigation toxicity tests for these substances in the glands, respectively (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Acetone was used as the solvent.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eChemicals used in the experiment\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMaterial name\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePurity level (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSupplier\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDecane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUndecane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTridecane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026ge;\u0026thinsp;98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTetradecane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePentadecane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHexadecane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAR, 98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCetene\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e94%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeptadecane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAR, 95%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNonadecane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAR, 98%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEicosane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeneicosane\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGC, \u0026gt;\u0026thinsp;99%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e13-Docosenamide\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCP\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMacklin, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAcetone\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eGuangzhou Chemical Reagent Factory, China\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003e①Fumigation method. According to the concentration range of the agents to be tested in the preliminary experiment, the reagents were serially diluted with acetone solution to five concentrations: 12.5 mg/L, 6.25 mg/L, 3.13 mg/L, 1.56 mg/L, and 0.78 mg/L. For this experiment, 250-mL glass bottles were used as the fumigation chamber. The test ants were placed in glass bottles for approximately 10 min. Then, 20 \u0026micro;L of the test solution was coated onto the paraffin film, and the glass bottle was sealed with the treated side. The upper part of the bottle was coated with talcum powder to prevent the ants from coming into contact with test substances. The test was performed on three ant nests, and each group was tested 3 times with 20 worker ants. The number of deaths due to \u003cem\u003eS. invicta\u003c/em\u003e was recorded at 6, 12, and 24 h. Because fumigation method is done in the bottle, it is best to observe the ants within it, the worker ants were considered dead if they curled.\u003c/p\u003e \u003cp\u003e②Topical application. Based on the concentration range of the agents to be tested in the preliminary experiment, each reagent was diluted with acetone solution to the same five test concentrations as those used in the fumigation method. One microliter of each drug mixture at different concentrations was placed on the pronota of large \u003cem\u003eS. invicta\u003c/em\u003e worker ants via a microsampler, and the ants were then transferred to a plastic bowl, whose inner wall was coated with talcum powder (to prevent \u003cem\u003eS. invicta\u003c/em\u003e from escaping the bowl). The acetone treatment was used as the control. Three replicates were performed for each concentration, and 15 worker ants were used in each replicate. Tests were performed on three ant nests. After 24 and 48 h of treatment, the number of worker ants that died was recorded. If worker ants were unable to stand up and move after being lightly touched with tweezers or had fewer than three legs, they were classified as dead.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e1.6 Statistical analysis\u003c/h2\u003e \u003cp\u003eThe data in this study were analyzed using Excel 2010 and SPSS Statistics 26.0. GraphPad Prism 8 software were used for graphing. Data that conforms to a normal distribution and homogeneous variance were analyzed using a one-way analysis of variance (ANOVA). Tukey\u0026rsquo;s test was used for multiple comparisons. The Tamhane's test Kruskal-Wallis test was used to test for non-normally distributed data. Then perform a Kruskal-Wallis single-factor analysis for multiple comparisons, and take the results of the Bonferroni multiple comparison test. Some data were analyzed using the independent samples T-test. For the toxicity test part, LC values, KT values, and LD values were calculated, using the Probit and Logit models.\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cimg src=\"data:image/png;base64,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\"\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003ewhere N I, N II, N III, and N IV are the number of behaviors at the corresponding attack level.\u003c/p\u003e \u003cp\u003eM = (U/N)\u0026times;100% (2)\u003c/p\u003e \u003cp\u003ewhere M is the mortality rate, U is the number of dead ants after testing, and N is the number of ants before testing.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results and analysis","content":"\u003cdiv id=\"Sec14\"\u003e\n \u003ch2\u003e2.1 Individual attack test\u003c/h2\u003e\n \u003cdiv id=\"Sec15\"\u003e\n \u003ch2\u003e2.1.1 Attack levels between different ants and \u003cem\u003eS. invicta\u003c/em\u003e\u003c/h2\u003e\n \u003cp\u003eTable 3 shows that both the total number of attacks and the number of level IV attacks by \u003cem\u003eT. melanocephalum\u003c/em\u003e are the lowest. The total number of attacks is significantly lower than that of four ant species: \u003cem\u003eP. dives\u003c/em\u003e, \u003cem\u003eC. japonicus\u003c/em\u003e, \u003cem\u003eC. nicobarensis\u003c/em\u003e, and \u003cem\u003eA. gracilipes\u003c/em\u003e (\u003cem\u003ep\u003c/em\u003e = 0.03, \u003cem\u003ep\u003c/em\u003e = 0.004, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). The number of level IV attacks is significantly lower than that of the other seven ant species (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). Combined with Fig. 3, it also has the lowest proportion in the Grade IV of small, medium, and large \u003cem\u003eS. invicta\u003c/em\u003e, which are 5.38%, 21.21%, and 11.11% respectively. The number of low-level attack (I, II) behaviors of \u003cem\u003eO. smaragdina\u003c/em\u003e is the lowest, which is significantly lower than that of the other seven ant species (\u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). Its proportions of the Grade I and II of small, medium, and large \u003cem\u003eS. invicta\u003c/em\u003e are also the lowest, which are 13.73%, 16.04%, and 17.36% respectively.\u003c/p\u003e\u0026nbsp;\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 3\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eIndividual attacks numbers between eight ant species and \u003cem\u003eS. invicta\u003c/em\u003e of different sizes.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\n \u003cp\u003e\u003cem\u003eO. smaragdina\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003eTotal number of attacks\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003eNumber of attacks (IV)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003eNumber of attacks\u003c/p\u003e\n \u003cp\u003e(I, II)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e3.66 ± 0.30 \u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e2.02 ± 0.23 \u003csup\u003eabc\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0.58 ± 0.07 \u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e\u003cem\u003eP. dives\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e4.49 ± 0.29 \u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e1.83 ± 0.15 \u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e1.72 ± 0.18 \u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e\u003cem\u003eC. japonicus\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e4.88 ± 0.34 \u003csup\u003eabc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e2.78 ± 0.24 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e1.17 ± 0.11 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e\u003cem\u003eC. nicobarensis\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e6.44 ± 0.45 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e2.40 ± 0.22 \u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e2.61 ± 0.26 \u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e\u003cem\u003eC. pseudoirritans\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e3.71 ± 0.24 \u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e1.49 ± 0.17 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e1.50 ± 0.13 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e\u003cem\u003eA. gracilipes\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e5.54 ± 0.35 \u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e1.58 ± 0.19 \u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e2.51 ± 0.16 \u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e\u003cem\u003eT. melanocephalum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e3.01 ± 0.34 \u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e0.32 ± 0.08 \u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e1.86 ± 0.24 \u003csup\u003eabc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e\u003cem\u003eP. megacephala\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e3.57 ± 0.25 \u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e1.86 ± 0.14 \u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e1.46 ± 0.14 \u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003eThe data in the table represent the mean ± standard error (SE) of 30 repetitions. The data with different letters indicate significant differences at a level of 0.05. (There is unequal variance, and the Tamhane test result shows that \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05).\u003c/p\u003e\n \u003c/div\u003e\n \u003cdiv id=\"Sec16\"\u003e\n \u003ch2\u003e2.1.2 Attack index between different ants and \u003cem\u003eS. invicta\u003c/em\u003e\u003c/h2\u003e\n \u003cp\u003eThe results of the attack index analysis (Table 4) revealed that the attack index of \u003cem\u003eC. nicobarensis\u003c/em\u003e against small \u003cem\u003eS. invicta\u003c/em\u003e workers was significantly greater than that against large workers (\u003cem\u003ep\u003c/em\u003e = 0.019). The attack indices of the remaining seven ant species and \u003cem\u003eS. invicta\u003c/em\u003e of different sizes did not differ significantly. Regardless of size, overall, \u003cem\u003eO. smaragdina\u003c/em\u003e and \u003cem\u003eS. invicta\u003c/em\u003e workers had the highest attack indices. The attack index of \u003cem\u003eT. melanocephalum\u003c/em\u003e was the lowest, significantly lower than that of the other seven ant species (with \u003cem\u003ep\u003c/em\u003e = 0.016 compared to \u003cem\u003eA. gracilipes\u003c/em\u003e, and \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001 for the others). The attack index of \u003cem\u003eA. gracilipes\u003c/em\u003e also showed significant differences with the other 5 ant species except \u003cem\u003eC. pseudoirritans\u003c/em\u003e (with \u003cem\u003ep\u003c/em\u003e = 0.002 compared to \u003cem\u003eC. nicobarensis\u003c/em\u003e, and \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001 for the others).\u003c/p\u003e\n \u003cp\u003eThe data in the table represent the mean ± standard error (SE) of 30 repetitions. The data in the first three columns were compared, and data with different letters indicate significant differences at a level of 0.05 (Tukey test, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05). The data in the last column are compared longitudinally, and data with different letters indicate that the difference is significant at the 0.05 level (Tamhane test, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05).\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec17\"\u003e\n \u003ch2\u003e2.2 Swarm attack tests\u003c/h2\u003e\n \u003cp\u003eAs shown in Fig.\u0026nbsp;4, there are statistical differences in the mortality rate of other ants to \u003cem\u003eS. invicta\u003c/em\u003e in different proportions, including 5:1 (\u003cem\u003eH\u003c/em\u003e = 73.745, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 3:1 (\u003cem\u003eH\u003c/em\u003e = 86.296, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 3:2 (\u003cem\u003eH\u003c/em\u003e = 85.979, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 1:1 (\u003cem\u003eH\u003c/em\u003e = 90.923, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 2:3 (\u003cem\u003eH\u003c/em\u003e = 85.833, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 1:3 (\u003cem\u003eH\u003c/em\u003e = 94.604, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 1:5 (\u003cem\u003eH\u003c/em\u003e = 84.025, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). Regardless of the ratio, the mortality rate of \u003cem\u003eS. invicta\u003c/em\u003e caused by \u003cem\u003eC. japonicus\u003c/em\u003e is the highest, while that caused by \u003cem\u003eT. melanocephalum\u003c/em\u003e is the lowest. The mortality rates of \u003cem\u003eS. invicta\u003c/em\u003e caused by \u003cem\u003eO. smaragdina\u003c/em\u003e, \u003cem\u003eC. japonicus\u003c/em\u003e, \u003cem\u003eP. dives\u003c/em\u003e, \u003cem\u003eA. gracilipes\u003c/em\u003e, and \u003cem\u003eT. melanocephalum\u003c/em\u003e gradually decrease as their numbers decrease. The mortality rate of \u003cem\u003eS. invicta\u003c/em\u003e caused by \u003cem\u003eT. melanocephalum\u003c/em\u003e is significantly lower than that caused by \u003cem\u003eO. smaragdina\u003c/em\u003e, \u003cem\u003eC. japonicus\u003c/em\u003e, and \u003cem\u003eA. gracilipes\u003c/em\u003e under all ratios (\u003cem\u003eO. smaragdina\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eC. japonicus\u003c/em\u003e: all \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eA. gracilipes\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.003, \u003cem\u003ep\u003c/em\u003e = 0.005, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.001). Meanwhile, under the ratios where the number of other ants is reduced, namely 1:1, 2:3, 1:3, and 1:5, it is also significantly lower than that caused by \u003cem\u003eC. nicobarensis\u003c/em\u003e and \u003cem\u003eC. pseudoirritans\u003c/em\u003e (\u003cem\u003eC. nicobarensis\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.003, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eC. pseudoirritans\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.006, \u003cem\u003ep\u003c/em\u003e = 0.022). The mortality rate of \u003cem\u003eS. invicta\u003c/em\u003e caused by \u003cem\u003eP. megacephala\u003c/em\u003e is significantly lower than that caused by \u003cem\u003eO. smaragdina\u003c/em\u003e and \u003cem\u003eC. japonicus\u003c/em\u003e under all ratios (\u003cem\u003eO. smaragdina\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.013, \u003cem\u003ep\u003c/em\u003e = 0.012; \u003cem\u003eC. japonicus\u003c/em\u003e: all \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). The mortality rate caused by \u003cem\u003eP. dives\u003c/em\u003e is significantly higher than that caused by \u003cem\u003eT. melanocephalum\u003c/em\u003e and \u003cem\u003eP. megacephala\u003c/em\u003e under the ratios of 5:1, 3:1, and 3:2 (\u003cem\u003eT. melanocephalum\u003c/em\u003e: all \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eP. megacephala\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e = 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.002). Moreover, under the ratios of 1:1, 2:3, 1:3, and 1:5, it is lower than that caused by \u003cem\u003eC. japonicus\u003c/em\u003e (all \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001).\u003c/p\u003e\n \u003cp\u003eAs shown in Fig.\u0026nbsp;5, there are statistical differences in the mortality rates of other ants in different proportions, including 5:1 (\u003cem\u003eH\u003c/em\u003e = 95.749, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 3:1 (\u003cem\u003eH\u003c/em\u003e = 86.472, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 3:2 (\u003cem\u003eH\u003c/em\u003e = 80.087, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 1:1 (\u003cem\u003eH\u003c/em\u003e = 81.692, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 2:3 (\u003cem\u003eH\u003c/em\u003e = 66.669, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 1:3 (\u003cem\u003eH\u003c/em\u003e = 83.642, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); 1:5 (\u003cem\u003eH\u003c/em\u003e = 80.056, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). Regardless of the ratio, the mortality rate of \u003cem\u003eP. megacephala\u003c/em\u003e in group competition was significantly higher than that of \u003cem\u003eP. dives\u003c/em\u003e, \u003cem\u003eC. japonicus\u003c/em\u003e, \u003cem\u003eC. nicobarensis\u003c/em\u003e, and \u003cem\u003eC. pseudoirritans\u003c/em\u003e (\u003cem\u003eP. dives\u003c/em\u003e: all \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eC. japonicus\u003c/em\u003e: all \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eC. nicobarensis\u003c/em\u003e: except for the 1:5 ratio with \u003cem\u003ep\u003c/em\u003e = 0.001, all \u003cem\u003ep\u003c/em\u003e values for other ratios were \u0026lt; 0.001; \u003cem\u003eC. pseudoirritans\u003c/em\u003e: all \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). The mortality rate of \u003cem\u003eT. melanocephalum\u003c/em\u003e was significantly higher than that of \u003cem\u003eO. smaragdina\u003c/em\u003e, \u003cem\u003eP. dives\u003c/em\u003e, \u003cem\u003eC. japonicus\u003c/em\u003e, \u003cem\u003eC. nicobarensis\u003c/em\u003e, and \u003cem\u003eC. pseudoirritans\u003c/em\u003e in the proportional ratios of 5:1, 3:1, and 3:2 (\u003cem\u003eO. smaragdina\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.002, \u003cem\u003ep\u003c/em\u003e = 0.002; \u003cem\u003eP. dives\u003c/em\u003e: all \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eC. japonicus\u003c/em\u003e: all \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eC. nicobarensis\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e = 0.001, \u003cem\u003ep\u003c/em\u003e = 0.006, \u003cem\u003ep\u003c/em\u003e = 0.001; \u003cem\u003eC. pseudoirritans\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.023, \u003cem\u003ep\u003c/em\u003e = 0.013). The mortality rate of \u003cem\u003eA. gracilipes\u003c/em\u003e in the 1:3 and 1:5 ratios was significantly higher than that of \u003cem\u003eP. dives\u003c/em\u003e, \u003cem\u003eC. japonicus\u003c/em\u003e, \u003cem\u003eC. nicobarensis\u003c/em\u003e, \u003cem\u003eC. pseudoirritans\u003c/em\u003e, and \u003cem\u003eT. melanocephalum\u003c/em\u003e (\u003cem\u003eP. dives\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e = 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eC. japonicus\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eC. nicobarensis\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.001; \u003cem\u003eC. pseudoirritans\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eT. melanocephalum\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). The mortality rate of \u003cem\u003eO. smaragdina\u003c/em\u003e in the 1:1 and 2:3 ratios was significantly higher than that of \u003cem\u003eP. dives\u003c/em\u003e, \u003cem\u003eC. nicobarensis\u003c/em\u003e, and \u003cem\u003eC. pseudoirritans\u003c/em\u003e (\u003cem\u003eP. dives\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e = 0.004, \u003cem\u003ep\u003c/em\u003e = 0.035; \u003cem\u003eC. nicobarensis\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e = 0.004, \u003cem\u003ep\u003c/em\u003e = 0.045; \u003cem\u003eC. pseudoirritans\u003c/em\u003e: \u003cem\u003ep\u003c/em\u003e = 0.008, \u003cem\u003ep\u003c/em\u003e = 0.002).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec18\"\u003e\n \u003ch2\u003e2.3 Sealing the acidopore\u003c/h2\u003e\n \u003cp\u003eSince the mortality rate of \u003cem\u003eT. melanocephalum\u003c/em\u003e and \u003cem\u003eP. megacephala\u003c/em\u003e against \u003cem\u003eS. invicta\u003c/em\u003e is very low, these two species of ants will no longer be used in subsequent experiments. The other six ants with nail polish and no \u003cem\u003eS. invicta\u003c/em\u003e compete, there is no mortality rate after 2h. Table 5 shows that after the acidopore was sealed, the mortality of \u003cem\u003eS. invicta\u003c/em\u003e caused by \u003cem\u003eO. smaragdina\u003c/em\u003e and \u003cem\u003eC. nicobarensis\u003c/em\u003e significantly decreased (\u003cem\u003et\u003c/em\u003e = 2.626, \u003cem\u003ep\u003c/em\u003e = 0.014; \u003cem\u003ez\u003c/em\u003e=-3.021, \u003cem\u003ep =\u003c/em\u003e 0.003), whereas the mortality of \u003cem\u003eO. smaragdina\u003c/em\u003e and \u003cem\u003eC. nicobarensis\u003c/em\u003e significantly increased (\u003cem\u003ez\u003c/em\u003e=-3.467, \u003cem\u003ep\u003c/em\u003e = 0.001; \u003cem\u003ez\u003c/em\u003e=-3.624, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). No significant difference was observed in the mortality of \u003cem\u003eS. invicta\u003c/em\u003e caused by \u003cem\u003eP. dives\u003c/em\u003e (\u003cem\u003ez\u003c/em\u003e=-0.172, \u003cem\u003ep\u003c/em\u003e = 0.863). The mortality rate of \u003cem\u003eP. dives\u003c/em\u003e was low (\u003cem\u003ez\u003c/em\u003e=-0.703, \u003cem\u003ep\u003c/em\u003e = 0.482). The mortality of \u003cem\u003eS. invicta\u003c/em\u003e caused by \u003cem\u003eC. japonicus\u003c/em\u003e significantly decreased (\u003cem\u003ez\u003c/em\u003e=-2.827, \u003cem\u003ep\u003c/em\u003e = 0.005), but the difference in the mortality of \u003cem\u003eC. japonicus\u003c/em\u003e was not significant (\u003cem\u003ez\u003c/em\u003e=-1.548, \u003cem\u003ep\u003c/em\u003e = 0.122); both rates decreased. With the nail polish sealant, \u003cem\u003eC. pseudoirritans\u003c/em\u003e caused more \u003cem\u003eS. invicta\u003c/em\u003e deaths than without the nail polish sealant (\u003cem\u003ez\u003c/em\u003e=-2.44, \u003cem\u003ep\u003c/em\u003e = 0.015), and the mortality of \u003cem\u003eC. pseudoirritans\u003c/em\u003e also significantly increased (\u003cem\u003ez\u003c/em\u003e=-3.097, \u003cem\u003ep\u003c/em\u003e = 0.002). The mortality of \u003cem\u003eS. invicta\u003c/em\u003e caused by \u003cem\u003eA. gracilipes\u003c/em\u003e was significantly reduced (\u003cem\u003et\u003c/em\u003e = 3.666, \u003cem\u003ep\u003c/em\u003e = 0.001), whereas the difference in mortality of \u003cem\u003eA. gracilipes\u003c/em\u003e after sealing was not significantly greater (\u003cem\u003ez\u003c/em\u003e = 0, \u003cem\u003ep\u003c/em\u003e = 1).\u003c/p\u003e\n \u003cp\u003eLowercase letters in the table indicate that the data in the first two columns and the last two columns were compared (If the data follows a normal distribution, the independent sample T-test was used; otherwise, a non-parametric test is used, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05). Capital letters indicate that the data in the same column are compared (Kruskal-Wallis single-factor analysis with multiple comparisons test, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.05). Data with different letters are significantly different at the 0.05 level.\u003c/p\u003e\n \u003cp\u003eThere are statistically significant differences in the mortality rates between \u003cem\u003eS. invicta\u003c/em\u003e and other ants when nail polish was applied to the acidopore at the end of the abdomen and to the lateral position of the abdomen, among which \u003cem\u003eS. invicta\u003c/em\u003e(\u003cem\u003eH\u003c/em\u003e = 47.917, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eH\u003c/em\u003e = 50.055, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001); other ants (\u003cem\u003eH\u003c/em\u003e = 61.404, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; \u003cem\u003eH\u003c/em\u003e = 54.503, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001). The lethality of \u003cem\u003eO. smaragdina\u003c/em\u003e, \u003cem\u003eP. dives\u003c/em\u003e, and \u003cem\u003eA. gracilipes\u003c/em\u003e against \u003cem\u003eS. invicta\u003c/em\u003e was significantly lower than that against \u003cem\u003eC. japonicus\u003c/em\u003e (acidopore: \u003cem\u003ep\u003c/em\u003e = 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001; false blockage: \u003cem\u003ep\u003c/em\u003e = 0.002, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001), regardless of the presence or absence of nail polish sealant. The mortality rates of \u003cem\u003eP. dives\u003c/em\u003e, \u003cem\u003eC. japonicus\u003c/em\u003e, and \u003cem\u003eC. pseudoirritans\u003c/em\u003e were significantly lower than those of \u003cem\u003eA. gracilipes\u003c/em\u003e with or without nail polish (acidopore: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e = 0.009; false blockage: \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001, \u003cem\u003ep\u003c/em\u003e \u0026lt; 0.001).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec19\"\u003e\n \u003ch2\u003e2.4 Identification of substances in the secretions of the Dufour glands and venom glands\u003c/h2\u003e\n \u003cp\u003eGC-MS revealed that the secretions of the Dufour glands and venom glands of the six ant species were mainly composed of alkanes supplemented by a few acids. As shown in Table\u0026nbsp;6, almost all pheromones secreted by the glands appeared earlier, and individual peaks with higher values appeared later. The main volatile components were decane, undecane, tridecane, tetradecane, pentadecane, hexadecane, hexadecene, heptadecane, nonadecane, eicosane, hexacane, and erucamide; among these components, undecane and tridecane were present in the secretions of all six ant species.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec20\"\u003e\n \u003ch2\u003e2.5 Comprehensive Analysis of Compound Toxicity to \u003cem\u003eS. invicta\u003c/em\u003e at Different Fumigation Durations\u003c/h2\u003e\n \u003cp\u003eIn the Probit model analysis of 6 h fumigation LC₂₀, 12 h fumigation LC₅₀, and 24 h fumigation LC₉₀, the toxicity of tested compounds to \u003cem\u003eS. invicta\u003c/em\u003e generally increased with prolonged exposure time, and there were orders-of-magnitude differences in toxicity among compounds.\u003c/p\u003e\n \u003cp\u003eAt 6 h(Table 7), hexadecane exhibited the strongest toxicity (LC₂₀ = 0.49 mg/L), followed by decane (4.00 mg/L) and tetradecane (5.30 mg/L), while nonadecane (2,337,743.97 mg/L) and heneicosane (9686.93 mg/L) showed extremely weak toxicity. When the fumigation duration was extended to 12 h༈Table 8༉, the overall toxicity was enhanced: hexadecane remained a highly toxic representative (LC₅₀ = 0.00 mg/L), and the LC₅₀ values of decane (0.01 mg/L), tetradecane (0.08 mg/L), and eicosane (0.52 mg/L) were all below 1 mg/L; in contrast, heneicosane (5,620,049,434,643.50 mg/L) and nonadecane (6966.67 mg/L) still displayed low toxicity.\u003c/p\u003e\u0026nbsp;\u003ctable float=\"Yes\" id=\"Tab7\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 7\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eLC20 values of different compounds for fumigating \u003cem\u003eS. invicta\u003c/em\u003e at the 6th\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eSubstance\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003eSlope ± SE\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003eLC20(mg/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eUndecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.36 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e12.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e5.86–191.50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTridecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.32 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e8.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e4.26-128.17\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003ePentadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.09 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e91.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeptadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.37 ± 0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e23.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e9.24-1695.45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eDecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.22 ± 0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e4.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e0.33-408755538079687420.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTetradecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.30 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e5.30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e2.43–36.59\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHexadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.45 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e0.09–0.99\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eCetene\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.21 ± 0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e1416.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eEicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.43 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e9.76\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e5.43–44.27\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eNonadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.16 ± 0.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e2337743.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeneicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.23 ± 0.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e9686.93\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e13-Docosenamide\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.33 ± 0.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e2766.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003eAt 24 h(Table 9), the toxicity of highly toxic compounds was further strengthened: eicosane became the most toxic substance (LC₉₀ = 0.016 mg/L), followed by tetradecane and hexadecane (both 0.128 mg/L), and decane (0.133 mg/L). Only tridecane maintained an extremely low toxicity level with an LC₉₀ of 10,155.754 mg/L.\u003c/p\u003e\n \u003cp\u003eOverall, hexadecane, decane, tetradecane, and eicosane were consistently highly toxic compounds at all tested durations, whereas nonadecane, heneicosane, and tridecane consistently showed low toxicity. Furthermore, the lethal concentration thresholds of highly toxic compounds continuously decreased with prolonged fumigation time, demonstrating a clear time-toxicity cumulative effect.\u003c/p\u003e\n \u003cdiv\u003e\n \u003cdiv align=\"left\" colname=\"c1\" colnum=\"1\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003ctable float=\"Yes\" id=\"Tab8\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 8\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eLC50 values of different compounds for fumigating \u003cem\u003eS. invicta\u003c/em\u003e at the 12th\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eSubstance\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003eSlope ± SE\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003eLC50(mg/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eUndecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.26 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e277.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e36.14-3358372201.45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTridecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.38 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e16.81\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e8.36-109.98\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003ePentadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.48 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e2.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e1.31–3.31\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeptadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.63 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e7.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e5.03–11.66\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eDecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.21 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0-0.16\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTetradecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.21 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.08\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0-0.52\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHexadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.21 ± 0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eCetene\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.24 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e2.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0.34–6.76\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eEicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.51 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0.15–0.94\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eNonadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.18 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e6966.67\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeneicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.04 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e5620049434643.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e13-Docosenamide\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.20 ± 0.10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e72.40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e13.11-2.649E + 168\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv\u003e\n \u003cdiv align=\"left\" colname=\"c1\" colnum=\"1\"\u003e\u0026nbsp;\u003c/div\u003e\n \u003ctable float=\"Yes\" id=\"Tab9\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 9\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eLC90 values of different compounds for fumigating \u003cem\u003eS. invicta\u003c/em\u003e at the 24th\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eSubstance\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003eSlope ± SE\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003eLC90(mg/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eUndecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.36 ± 0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e5.043\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e2.55–33.56\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTridecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.18 ± 0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e10155.754\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003ePentadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.69 ± 0.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.654\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e0.15–1.17\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeptadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.99 ± 0.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e1.769\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e1.28–2.38\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eDecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e1.10 ± 0.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.133\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTetradecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.75 ± 0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.128\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e0-0.47\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHexadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.75 ± 0.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.128\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e0-0.47\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eCetene\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.65 ± 0.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.383\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e0.02–0.85\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eEicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.34 ± 0.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eNonadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.43 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e10.025\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e5.22–63.28\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeneicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.31 ± 0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e2.981\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e1.01–11.85\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e13-Docosenamide\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.89 ± 0.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.562\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e0.16–0.95\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv\u003e\n \u003cdiv align=\"left\" colname=\"c1\" colnum=\"1\"\u003e\u003cbr\u003e\u003c/div\u003e\n \u003cdiv align=\"char\" char=\"±\" colname=\"c2\" colnum=\"2\"\u003e\u003cbr\u003e\u003c/div\u003e\n \u003ctable float=\"Yes\" id=\"Tab10\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 10\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eKT50 values of different compounds at a concentration of 0.78mg/L\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eSubstance\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003eSlope ± SE\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003eKT50(h)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eUndecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e2.83 ± 0.48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e33.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e22.97–70.37\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTridecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e3.77 ± 0.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e21.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e16.94–29.83\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003ePentadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e4.58 ± 0.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e15.55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e13.63–18.84\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeptadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e4.32 ± 0.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e20.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e16.84–28.75\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eDecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e6.97 ± 0.59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e10.99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e9.47–14.35\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTetradecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e6.32 ± 0.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e10.97\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e10.30-11.85\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHexadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e4.98 ± 0.39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e9.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e7.15–13.26\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eCetene\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e7.59 ± 0.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e13.22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e12.27–14.65\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eEicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e6.81 ± 0.61\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e11.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e10.99–12.74\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eNonadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e6.58 ± 0.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e18.80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e15.94-25.00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeneicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e8.00 ± 0.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e14.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e13.60-17.34\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e13-Docosenamide\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e10.06 ± 1.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e13.73\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\n \u003cp\u003e12.80–15.20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003eAt a fixed concentration of 0.78 mg/L, the results of KT50 (median knockdown time) obtained based on Logit model fitting showed that there were significant differences in the speed of knockdown of \u003cem\u003eS. invicta\u003c/em\u003e by the tested compounds. Hexadecane had the fastest knockdown speed, with a KT50 of only 9.05 h (95% confidence interval: 7.15–13.26 h), and the dose-effect relationship was robust (slope = 4.98 ± 0.39). Decane (10.99 h), tetradecane (10.97 h), and eicosane (11.73 h) also exhibited relatively fast knockdown activity, with KT50 values all within 12 h. The knockdown speeds of hexadecene (13.22 h), erucamide (13.73 h), heneicosane (14.98 h), and pentadecane (15.55 h) were next, with KT50 values ranging from 13 to 16 h. Heptadecane (20.62 h), tridecane (21.00 h), nonadecane (18.80 h), and undecane (33.68 h) had slower knockdown speeds. Among them, undecane had the highest KT50 and the slowest knockdown effect. Overall, hexadecane was the compound with the fastest speed in knocking down \u003cem\u003eS. invicta\u003c/em\u003e, while undecane had the slowest knockdown speed. The difference in KT50 among the tested compounds exceeded 3 times, reflecting significant differences in knockdown activity.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec21\"\u003e\n \u003ch2\u003e2.6 Comprehensive analysis of toxicity of different compounds by topical application on \u003cem\u003eS. invicta\u003c/em\u003e\u003c/h2\u003e\n \u003cp\u003eThe acute lethal effects of the tested compounds on \u003cem\u003eS. invicta\u003c/em\u003e were further investigated via topical application bioassays, with LD₅₀ (24 h) and LD₉₀ (48 h) calculated using the Probit model. The results demonstrated significant differences in acute toxicity among compounds, and the lethal dose thresholds of highly toxic compounds continued to decrease with prolonged observation time, confirming the time-dependent toxicity enhancement (Tables 11 and 12).\u0026nbsp;\u003c/p\u003e\n \u003ctable float=\"Yes\" id=\"Tab11\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 11\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eLD50 values of different compounds against \u003cem\u003eS. invicta\u003c/em\u003e at 24 hours using the Topical application\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eSubstance\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003eSlope ± SE\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003eLD50(ng/ant)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eUndecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.76 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e8.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e3.76-239.38\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTridecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.28 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e94.99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e18.68-209608217.96\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003ePentadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.20 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e5307.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeptadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.34 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0.02–1.35\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eDecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.35 ± 0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e5.88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e3.15–26.17\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTetradecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.20 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e783.96\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHexadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.38 ± 0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0-0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eCetene\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.43 ± 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e17.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e8.49-144.91\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eEicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.50 ± 0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e88.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e28.14-2266.20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eNonadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.49 ± 0.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e0.01\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0-0.07\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeneicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.49 ± 0.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e18.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e10.09–70.60\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e13-Docosenamide\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.28 ± 0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\n \u003cp\u003e2.99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0.74–10.21\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003cp\u003eIn the 24 h topical LD₅₀ assay, hexadecane and nonadecane displayed extremely strong acute toxicity, both with an LD₅₀ of 0.01 ng/ant. Hexadecane showed a robust dose–response relationship (slope = 0.38 ± 0.13) with a 95% confidence interval (CI) of 0–0.13 ng/ant. Heptadecane was the next most toxic compound, with an LD₅₀ of 0.58 ng/ant (95% CI: 0.02–1.35 ng/ant). Erucamide (2.99 ng/ant, 95% CI: 0.74–10.21 ng/ant), decane (5.88 ng/ant, 95% CI: 3.15–26.17 ng/ant), and undecane (8.02 ng/ant, 95% CI: 3.76–239.38 ng/ant) also exhibited relatively high acute toxicity. In comparison, hexadecene (17.68 ng/ant), heneicosane (18.58 ng/ant), eicosane (88.03 ng/ant), and tridecane (94.99 ng/ant) showed moderate toxicity. Tetradecane (783.96 ng/ant) and pentadecane (5307.35 ng/ant) had extremely high LD₅₀ values, indicating extremely weak acute toxicity. Notably, some compounds showed extremely wide or missing 95% CIs, suggesting poor stability in their dose–response relationships.\u003c/p\u003e\n \u003cp\u003eIn the 48 h topical LD₉₀ assay, the lethal activity of highly toxic compounds was further enhanced. Hexadecane remained the most toxic compound with an LD₉₀ of only 0.02 ng/ant (slope = 0.67 ± 0.57). Decane (0.11 ng/ant), nonadecane (0.38 ng/ant, 95% CI: 0.02–0.73 ng/ant), hexadecene (0.52 ng/ant, 95% CI: 0.07–0.99 ng/ant), and tetradecane (0.91 ng/ant, 95% CI: 0.17–1.66 ng/ant) also displayed extremely high lethal activity, with all LD₉₀ values below 1 ng/ant. Heptadecane had an LD₉₀ of 0 ng/ant, indicating that a 90% lethal effect could be achieved at an extremely low dose. Undecane (1.34 ng/ant, 95% CI: 0.00–3.42 ng/ant) showed moderate toxicity. In contrast, tridecane (11.58 ng/ant), erucamide (28.64 ng/ant), heneicosane (30.98 ng/ant), eicosane (57.83 ng/ant), and pentadecane (65.72 ng/ant) had significantly higher LD₉₀ values, reflecting weak lethal activity.\u003c/p\u003e\u0026nbsp;\u003ctable float=\"Yes\" id=\"Tab12\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 12\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eLD50 values of different compounds against \u003cem\u003eS. invicta\u003c/em\u003e at 48 hours using the Topical application\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eSubstance\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003eSlope ± SE\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003eLD90(ng/ant)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eUndecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.35 ± 0.17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e1.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0.00-3.42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTridecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.49 ± 0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e11.58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e5.81–85.85\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003ePentadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.40 ± 0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e65.72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e17.82-14769.20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeptadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.25 ± 0.34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eDecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.49 ± 0.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e0.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eTetradecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.62 ± 0.20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e0.91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0.17–1.66\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHexadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.67 ± 0.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eCetene\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.84 ± 0.26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e0.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0.07–0.99\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eEicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.57 ± 0.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e57.83\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e22.17–556.70\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eNonadecane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e1.22 ± 0.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e0.38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e0.02–0.73\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHeneicosane\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.56 ± 0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e30.98\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e13.58-229.41\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003e13-Docosenamide\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\" char=\"±\" colname=\"c2\"\u003e\n \u003cp\u003e0.47 ± 0.13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e28.64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c4\"\u003e\n \u003cp\u003e11.33-507.49\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"Conclusion and discussion","content":"\u003cp\u003eIn this study, mock competition experiments involving \u003cem\u003eS. invicta\u003c/em\u003e and eight other ant species were conducted. In individual attack experiments, the proportion of low-level attacks (Grades I and II) by \u003cem\u003eT. melanocephalum\u003c/em\u003e was the highest, while the total number of attacks and the number of level IV attacks were the lowest. This indicates that \u003cem\u003eT. melanocephalum\u003c/em\u003e mostly stays in a evasive state during individual competition and will not take the initiative to attack \u003cem\u003eS. invicta\u003c/em\u003e. The results of competition experiments between \u003cem\u003eT. melanocephalum\u003c/em\u003e and \u003cem\u003eS. invicta\u003c/em\u003e revealed that \u003cem\u003eT. melanocephalum\u003c/em\u003e also stayed away from \u003cem\u003eS. invicta\u003c/em\u003e, thus avoiding attack (Huang \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). The proportion of the level IV attacks by \u003cem\u003eO. smaragdina\u003c/em\u003e and \u003cem\u003eO. smaragdina\u003c/em\u003e is relatively high among large other ants, and their attack indices are also relatively large. This indicates that these two species of ants will choose to actively attack when facing \u003cem\u003eS. invicta\u003c/em\u003e, and can kill \u003cem\u003eS. invicta\u003c/em\u003e in a short period of time.\u003cem\u003eC. pseudoirritans\u003c/em\u003e would stand still in the early stage of competition with \u003cem\u003eS. invicta\u003c/em\u003e until the \u003cem\u003eS. invicta\u003c/em\u003e individual touched it; otherwise, the two ants would not attack each other. \u003cem\u003eC. pseudoirritans\u003c/em\u003e has the habit of feigning death; therefore, it is speculated that they use this method to evade attacks when encountering large \u003cem\u003eS. invicta\u003c/em\u003e. Therefore, the attack index of the proposed \u003cem\u003eC. pseudoirritans\u003c/em\u003e and the proportion of attacks at Grades III and IV were also relatively small.\u003c/p\u003e \u003cp\u003eIn group competition, the mortality rate of \u003cem\u003eS. invicta\u003c/em\u003e. caused by \u003cem\u003eT. melanocephalum\u003c/em\u003e is the lowest. Under the proportional ratios of 5:1, 3:1, and 3:2 (i.e., when the number of \u003cem\u003eT. melanocephalum\u003c/em\u003e is larger), their own mortality rate is higher. When the number of \u003cem\u003eT. melanocephalum\u003c/em\u003e decreases, their own mortality rate reduces. This may be because \u003cem\u003eT. melanocephalum\u003c/em\u003e has a small size and a relatively fast movement speed, making them difficult to catch. Although the attack index of \u003cem\u003eP. megacephala\u003c/em\u003e is significantly higher than that of \u003cem\u003eA. gracilipes\u003c/em\u003e and \u003cem\u003eT. melanocephalum\u003c/em\u003e, their own mortality rate is the highest in group competition, indicating that \u003cem\u003eP. megacephala\u003c/em\u003e has no advantage in competition with \u003cem\u003eS. invicta\u003c/em\u003e.\u003c/p\u003e \u003cp\u003eIn the 1:1 colony attack experiment, three biological control species (\u003cem\u003eP. dives\u003c/em\u003e, \u003cem\u003eO. smaragdina\u003c/em\u003e and \u003cem\u003eC. japonicus\u003c/em\u003e) and two native species (\u003cem\u003eC. nicobarensis\u003c/em\u003e and \u003cem\u003eC. pseudoirritans\u003c/em\u003e) indeed inhibited the invasion of \u003cem\u003eS. invicta\u003c/em\u003e. Moreover, the mortality rate of \u003cem\u003eS. invicta\u003c/em\u003e caused by \u003cem\u003eC. japonicus\u003c/em\u003e was over 95% under all seven proportion conditions, indicating that \u003cem\u003eC. japonicus\u003c/em\u003e has strong attack power.\u003c/p\u003e \u003cp\u003eInterspecific competition is the main process involved in the construction of ecological communities. Under the influence of phenotypic differences among species, the limited similarity theory suggests that species with similar shapes could strongly replace other species, and that the final result is competitive replacement. Biological invasion often leads to strong competitive interactions, and is a suitable model for investigating competition (Shea et al. 2002; Dunham and Mikheyev \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). For example, before the arrival of \u003cem\u003eS. invicta\u003c/em\u003e, \u003cem\u003eSolenopsis geminata\u003c/em\u003e and \u003cem\u003eSolenopsis xyloni\u003c/em\u003e MacCook were the dominant species in their corresponding regions (Porter and Savignano \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e1990\u003c/span\u003e), but when \u003cem\u003eS. invicta\u003c/em\u003e invaded, the tropical fire ant was the first to be replaced. There are reported a clear competitive relationship between \u003cem\u003eS. invicta\u003c/em\u003e and \u003cem\u003eCamponotus lensus\u003c/em\u003e and \u003cem\u003eCamponotus dolendus\u003c/em\u003e through interference and resource predation competition (Xi et al. \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Recent research suggests that the coexistence mechanism between indigenous ants and invasive \u003cem\u003eS. invicta\u003c/em\u003e involves behavioral plasticity (Tschinkel \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2006\u003c/span\u003e), resource utilization differentiation (Lebrun et al. \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2012\u003c/span\u003e), and competition defense trade-offs (Stuble et al. \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2009\u003c/span\u003e), rather than simply a balance of offensive and defensive abilities. The native ant species that coexist with \u003cem\u003eS. invicta\u003c/em\u003e have varying degrees of control over \u003cem\u003eS. invicta\u003c/em\u003e (Allen et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1994\u003c/span\u003e), and this control comes mainly from interspecific competition. In its native area in Brazil, the proportion of \u003cem\u003eS. invicta\u003c/em\u003e (which represents the population density to a certain extent) is lower than that in the United States (Porter et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e1992\u003c/span\u003e). There are studied the competitiveness of \u003cem\u003eT. melanocephalum\u003c/em\u003e and \u003cem\u003ePheidole fervida\u003c/em\u003e Smith against \u003cem\u003eS. invicta\u003c/em\u003e, and reported that the attack intensity between \u003cem\u003eT. melanocephalum\u003c/em\u003e and \u003cem\u003eS. invicta\u003c/em\u003e was relatively weak, whereas \u003cem\u003ePheidole fervida\u003c/em\u003e Smith and \u003cem\u003eS. invicta\u003c/em\u003e attacked each other intensely, resulting in increased mortality (Gao et al. \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Therefore, many scholars believe that this competition may be a factor controlling the invasiveness of \u003cem\u003eS. invicta\u003c/em\u003e. These studies indicate that interactions between \u003cem\u003eS. invicta\u003c/em\u003e and other ants limit \u003cem\u003eS. invicta\u003c/em\u003e (Tschinkel \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2006\u003c/span\u003e; Stimac and Alves \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e1994\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eQuantitative advantage is also critical in interspecific competition among ants (Holway et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2002\u003c/span\u003e). As the number of \u003cem\u003eP. dives\u003c/em\u003e and \u003cem\u003eA. gracilipes\u003c/em\u003e increases, their lethality rate against \u003cem\u003eS. invicta\u003c/em\u003e also rises, indicating that when these two species of ants are present in sufficient numbers, they also can completely resist attacks by \u003cem\u003eS. invicta\u003c/em\u003e, and thus has a strong competitive advantage. However, at ratios of 1:3 and 1:5, when \u003cem\u003eS. invicta\u003c/em\u003e had a numerical advantage, \u003cem\u003eA. gracilipes\u003c/em\u003e was at a disadvantage, even with its defensive secretions. Although the mortality rate of \u003cem\u003eT. melanocephalum\u003c/em\u003e and \u003cem\u003eP. megacephala\u003c/em\u003e against \u003cem\u003eS. invicta\u003c/em\u003e is very low, when the ratio is 5:1, their mortality rate against \u003cem\u003eS. invicta\u003c/em\u003e reaches the highest value among all ratios. At the end of the experiment, many broken legs or abdomens of \u003cem\u003eS. invicta\u003c/em\u003e were observed in the boxes containing \u003cem\u003eO. smaragdina\u003c/em\u003e, \u003cem\u003eC. japonicus\u003c/em\u003e, \u003cem\u003eC. nicobarensis\u003c/em\u003e and \u003cem\u003eC. pseudoirritans\u003c/em\u003e, indicating that these four types of ants have a powerful mandible and strong biting ability. These ants not only use their strong mandibles to attack \u003cem\u003eS. invicta\u003c/em\u003e but also secrete substances to defend themselves against \u003cem\u003eS. invicta\u003c/em\u003e. During the experiment, a pungent odor was often detected around the small box, indicating that ants not only use their mandibles to fight \u003cem\u003eS. invicta\u003c/em\u003e, but also attack \u003cem\u003eS. invicta\u003c/em\u003e by secreting venom from the abdomen. The venom can cause the ant\u0026rsquo;s feet to stick and the body to twitch, and the ant slowly curls up until it dies. Phylogenetic studies have shown that Formicinae have undergone a reduction in venom gland development during their evolutionary history, leading to an adaptive trait of spraying formic acid and other defensive secretions through specialized acidpores (Touchard et al. \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Therefore, when nail polish is used to block the end of the abdomen acidpore of an ant to prevent the secretion of venom, the mortality of \u003cem\u003eS. invicta\u003c/em\u003e differs considerably during colony attack. In addition, nail polish itself does not threaten ant ant mortality. In addition, in Experiment 1.3 (i), applying nail polish to the abdomen of \u003cem\u003eS. invicta\u003c/em\u003e did not cause their death within 2 hours, and the survival rate was 100% (Lebrun EG et al. \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2014\u003c/span\u003e). So in the experiments in which the nail polish was used to seal the acidopore, the mortality of \u003cem\u003eS. invicta\u003c/em\u003e caused by \u003cem\u003eO. smaragdina\u003c/em\u003e, \u003cem\u003eC. japonicus\u003c/em\u003e, \u003cem\u003eC. nicobarensis\u003c/em\u003e and \u003cem\u003eA. gracilipes\u003c/em\u003e was significantly lower than that when the orifice was not sealed.\u003c/p\u003e \u003cp\u003eWhat are these secretions? The results of this experiment revealed that the types of compounds within ant secretions included alkanes, acids, benzene, alkenes, and a small amount of other substances; the content of alkanes was the highest, and undecane and tridecane were present in all six ant species. Two types of glands in ants, namely the venom glands and the Dufour glands (Gullan and Cranston \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2014\u003c/span\u003e), secrete, store, and excretory chemical substances. The main function of the venom glands is to produce defensive venom (Shang \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2006\u003c/span\u003e), and the excretion of toxins through venom glands is part of a relatively complex mechanism for prey capture and defense (Lima et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). The secretions of the Dufour glands contain linear alkanes and small amounts of alkenes and alkynes. These substances have various functions, the most primitive of which are related to female reproduction. Undecane, tridecane, decyl acetate, and dodecyl acetate secreted by the Dufour glands also have defensive functions. There are analyzed the substances from the Dufour glands and venom glands of \u003cem\u003eNylanderia fulva\u003c/em\u003e and revealed that the main substances were formic acid, undecane and 2-tridecanone; both undecane and 2-tridecanone had some contact toxicity against \u003cem\u003eS. invicta\u003c/em\u003e (Chen et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Formic acid is widely present in ants, such as Formica rufa Linnaeus, and is a key defensive secretion (Morgan \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2008\u003c/span\u003e), and it is worth considering for the prevention and control of \u003cem\u003eS. invicta\u003c/em\u003e (Chen et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2012\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe results of this study show that in the fumigation test, hexadecane had the lowest LC value and KT50; in the topical application, nonadecane and hexadecane had the lowest LD values. This indicates that these two compounds have the strongest toxicity to \u003cem\u003eS. invicta\u003c/em\u003e. Among them, hexadecane was detected only in \u003cem\u003eO. smaragdina\u003c/em\u003e, whereas nonadecane was detected in all other species except \u003cem\u003eC. japonicus\u003c/em\u003e and \u003cem\u003eP. dives\u003c/em\u003e. In this study, \u003cem\u003eC. japonicus\u003c/em\u003e presented a significant advantage in terms of group competition and had the highest mortality rate against \u003cem\u003eS. invicta\u003c/em\u003e. However, substances with relatively high contents in the secretions were not significantly toxic to \u003cem\u003eS. invicta\u003c/em\u003e. In the nail polish experiment, there was no significant difference in the self-mortality rate of \u003cem\u003eC. japonicus\u003c/em\u003e with nail polish on the abdomen, indicating that \u003cem\u003eC. japonicus\u003c/em\u003e mainly rely on the tearing and bite ability of the upper jaw to compete with \u003cem\u003eS. invicta\u003c/em\u003e and have strong fighting ability. But it is possible that toxic substances in the secretions of \u003cem\u003eC. japonicus\u003c/em\u003e are present at extremely low levels, requiring further screening and testing of the identified substances. Alkanes, such as nonadecane and hexadecane, have been studied only for their important roles in aggregation and individual communication. For example, bark beetles largely use volatile n-alkanes from the host to search for and identify hosts and for interspecific chemical communication (Fan et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Although there are few studies on their toxic effects, alkanes may be diffusion agents for formic acid or alkaloids; however, this has not been confirmed (Chen et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2013\u003c/span\u003e), in the future, the two glands will be extracted separately and further studied.\u003c/p\u003e \u003cp\u003eIn summary, \u003cem\u003eS. invicta\u003c/em\u003e is characterized by strong interspecific aggressiveness, high biological activity, and large colonies. This species often changes the composition of the ecological community in invaded areas and often eliminates native ants from competition. The current study revealed that the competition between individual worker ants includes physical and chemical attacks. Physical attacks depend on the size and agility of worker ants. For example, there are reported that \u003cem\u003eT. melanocephalum\u003c/em\u003e, in a one-on-one interaction with a competitor, uses physical attacks and chemical defense substances simultaneously (Li et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). In this article, the mortality rate of \u003cem\u003eT. melanocephalum\u003c/em\u003e in competition with \u003cem\u003eS. invicta\u003c/em\u003e is indeed low. There may be some substances that keep \u003cem\u003eS. invicta\u003c/em\u003e away from them, but these substances do not cause the death of \u003cem\u003eS. invicta\u003c/em\u003e. Therefore, the secretions of \u003cem\u003eT. melanocephalum\u003c/em\u003e were not extracted in this article, and further research can be conducted later. The experimental results revealed that \u003cem\u003eS. invicta\u003c/em\u003e has a definite advantage in terms of interspecific competition with smaller ants. However, when \u003cem\u003eS. invicta\u003c/em\u003e encounters larger ants or those that can secrete defensive chemical substances, increasing the number of \u003cem\u003eS. invicta\u003c/em\u003e will also increase the mortality rate of local ants. This experiment further demonstrated the threat of \u003cem\u003eS. invicta\u003c/em\u003e invasion of native ants and its impact on the ecosystem. However, these findings also revealed that native ants have an inhibitory effect on \u003cem\u003eS. invicta\u003c/em\u003e invasion (Vogt et al. \u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). The use of chemical agents is effective for the control of \u003cem\u003eS. invicta\u003c/em\u003e (Drees et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2013\u003c/span\u003e), but improper treatment not only pollutes the environment and causes a certain degree of nest migration, but also leads to a decrease in the number of native ants, resulting in a relatively high invasion density of \u003cem\u003eS. invicta\u003c/em\u003e (Morehart et al. \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Holmes et al. 2013). Therefore, when integrated control strategies for \u003cem\u003eS. invicta\u003c/em\u003e in different habitats are considered, the defense ability of local ants can be used to strengthen the control of \u003cem\u003eS. invicta\u003c/em\u003e.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research was funded by the Science \u0026amp; Technology Planning Project of Guangdong (2024B1212050005) and Shenzhen Wild Animal and Plant Protection Administration Division.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest declaration\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflicts of interest associated with this work.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAdams ES and Traniello JF (1981) Chemical interference competition by monomorium minimum (hymenoptera: formicidae). 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Journal of Environmental Entomology 31(2):156\u0026ndash;161\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Table 4 To 6","content":"\u003cp\u003eTable 4 To 6 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"S. invicta, other ants, competition, confrontation, pheromones","lastPublishedDoi":"10.21203/rs.3.rs-9183057/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9183057/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cem\u003eSolenopsis invicta\u003c/em\u003e Buren is one of the most important invasive pests in China and competes aggressively with native ants. This study investigated competitive interactions between eight ant species and \u003cem\u003eS. invicta\u003c/em\u003e, and the defensive chemicals involved, using individual and group competition tests and toxicity bioassays. Results showed that \u003cem\u003eTapinoma melanocephalum\u003c/em\u003e exhibited the lowest attack frequency against \u003cem\u003eS. invicta\u003c/em\u003e in individual contests, while \u003cem\u003ePheidole megacephala\u003c/em\u003e caused low mortality in group trials. \u003cem\u003eCamponotus japonicus\u003c/em\u003e showed the highest level IV attack intensity and caused the highest mortality, followed by \u003cem\u003eOecophylla smaragdina\u003c/em\u003e. \u003cem\u003eCamponotus nicobarensis\u003c/em\u003e and \u003cem\u003eCamponotus pseudoirritans\u003c/em\u003e achieved the highest mortality at a 1:1 ratio. Mortality caused by \u003cem\u003ePolyrhachis dives\u003c/em\u003e and \u003cem\u003eAnoplolepis gracilipes\u003c/em\u003e decreased with increasing numbers of \u003cem\u003eS. invicta\u003c/em\u003e. Blocking acid gland pores significantly reduced mortality by these dominant species. Toxicity tests indicated that hexadecane had the strongest fumigation toxicity, while hexadecane and nonadecane showed the highest contact toxicity. These findings suggest that several native ant species can competitively suppress \u003cem\u003eS. invicta\u003c/em\u003e, and their defensive pheromones play a key role. Utilizing such native ants could contribute to integrated management of \u003cem\u003eS. invicta\u003c/em\u003e.\u003c/p\u003e","manuscriptTitle":"Interspecific competition between Solenopsis invicta Buren and eight other ant species","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-02 14:49:45","doi":"10.21203/rs.3.rs-9183057/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"58869814-dfdb-4f77-aa43-b3f916f457b9","owner":[],"postedDate":"April 2nd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-23T14:40:37+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-02 14:49:45","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9183057","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9183057","identity":"rs-9183057","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}