Fitness consequences of host switching by Psix saccharicola, a stink bug egg parasitoid in pistachio orchards

Fitness consequences of host switching by Psix saccharicola, a stink bug egg parasitoid in pistachio orchards | 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 Fitness consequences of host switching by Psix saccharicola, a stink bug egg parasitoid in pistachio orchards Abbas Esmaeili Sardary, Fatemeh Ranjbar, Sabrina L. Celis, M. Amin Jalali, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5185542/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 To successfully implement augmentative biological control, it is imperative to identify the most efficient host for parasitoid rearing and the impact of host switching on reproduction when multiple hosts are available. This study examined the effect of host switching on parasitoid fitness and reproduction using the wasp Psix saccharicola Mani (Hymenoptera: Scelionidae), a dominant stink bug egg parasitoid in Iranian pistachio orchards, and two common hosts— Acrosternum arabicum Wagner (Hemiptera: Pentatomidae) and Brachynema germari Kolenati (Hemiptera: Pentatomidae). The results indicated that rearing wasps on A. arabicum was more efficient, resulting in a shorter population doubling time, a shorter mean generation time, and higher finite and intrinsic rates of increase compared to rearing on B. germari . While switching the host from A. arabicum to B. germari led to increased population growth parameters for P. saccharicola in the first generation of host switching, switching the host from B. germari to A. arabicum decreased parasitoid fitness and reproduction. However, the effect of host switching largely disappeared in the second generation after host-switch, suggesting that changes in parasitoid fitness due to host switching could be temporary and may revert in subsequent generations. Our study highlights the importance of evaluating the impact of host switching when implementing a rearing program for P. saccharicola , ultimately leading to more sustainable pest control of stink bugs in pistachio orchards. biological control life table Pentatomidae Hymenoptera Scelionidae Figures Figure 1 Figure 2 INTRODUCTION Pistachio ( Pistachio vera L.) is a significant commercial nut in Iran, the world’s top producer and exporter, prompting meticulous study of its pests and management options (Pakravan and Kavoosi-Kalashami 2011; Zheng et al. 2012 ). Stink bugs in the family Pentatomidae are among the predominant pests inflicting damage to pistachio trees. This group of insects, comprised of invasive species as well as emerging native pests, is assuming a pivotal role as pests on a variety of crop plants (Mehrnejad 2020 ). Acrosternum arabicum Wagner (Hemiptera: Pentatomidae) and Brachynema germari Kolenati (Hemiptera: Pentatomidae) are two native, economically significant species, and are the two most abundant pentatomid species found in Iranian pistachio orchards. These pests pose substantial challenges to growers due to their broad host range, long-term pest activity spanning from initial floral growth to post-harvest storage, and their potential to transmit pathogens (Mehrnejad 2001 ). Direct feeding on immature pistachio nuts by stink bugs can lead to dropped nut clusters, discoloration, deformation, and even the abortion of fruiting structures. As shells harden, feeding can cause necrosis and impart a bitter taste to the nut. Feeding may also result in indirect consequences such as transmission of the fungal pathogen Eremothecium coryli Kurtzman, causing stigmatomycosis. This results in foul-smelling, slimy nuts that are unfit for sale (Ershad and Barkhordary 1974 ). If stink bug population reaches injury levels of more than two female adults per 100 tree branches, these pests have the potential to damage over 60% of the orchard’s pistachio yield. Chemical insecticides, like organophosphates and pyriproxyfen, have been utilized to combat these pests (Mehrnejad et al. 2013 ; Mehrnejad 2020 ; Mehrnejad 2024 ). Biological control strategies seem to be promising alternatives for pentatomid control, protecting crop quality and quantity while reducing the need for pesticide applications (Ershad and Barkhordary 1974 ; Uyemoto et al. 1986 ; Ferguson and Haviland 2016 ). Egg parasitoid wasps are dominant biological control agents in stink bug pest management, with many species currently being studied (Abram et al. 2020 ; Conti et al. 2021 ). Two decades of parasitoid surveys in pistachio orchards documented ten wasps in the families Encyrtidae and Scelionidae that actively parasitize A. arabicum and B. germari eggs. Psix saccharicola Mani (Hymenoptera: Scelionidae) was one of the most dominant egg parasitoids in this survey due to its high female-to-male sex-ratio and parasitism rate, and as a result it has been identified as a potential biological control agent (Orr 1988 ; Ranjbar et al. 2021a ; Ranjbar et al. 2021b ). To develop a program for the mass-release of P. saccharicola in pistachio orchards, it is important to determine the most efficient host for rearing. Host switching can be used to evaluate the impact of a potential host species on parasitoid fitness in comparison to other hosts (Cornell and Pimentel 1978 ). During the host switching tests by Cornell and Pimentel ( 1978 ), a remarkable revelation emerged: while one host might be convenient and efficient for rearing, transferring the parasitoid's offspring to another host can lead to a substantial reduction in parasitism rate. Additionally, the use of an alternative host could influence development time and body size, both of which impact female fecundity (Smith et al. 1995 ). On a contrasting note, plasticity in parasitoid behavior when encountering a new host may result in net population growth even if other factors affecting reproduction, such as oviposition rate, are negatively impacted (Bourchier et al. 1994 ; Dyck et al. 2021 ). This is important to consider when rearing biological control agents, especially those used to control a different species than what they are reared on, or multiple species as in the case of P. saccharicola. Also, while rearing on a single host may be sufficient in some cases, concerns arise regarding parasitoid fitness when it is reared on the same host for more than three generations in laboratory conditions (Bigler 1989 ; Bourchier et al. 1994 ; Samková et al. 2021 ). Consequently, host switching tests are indispensable to ensure the viability of long-term parasitoid rearing and to assess the indirect risks associated with mass parasitoid releases (Chow and Mackauer 1991 ; Drost and Carde 1992; Fowler et al. 2022 ). Recently, there have been extensive studies on host switching in parasitoids and how the use of multiple hosts may impact production as well as biological control efficacy. In Ghaemmaghami et al. ( 2023 ), researchers found that rearing a parasitoid on one host resulted in a lower functional response to another host, even when the alternative host is more readily available in the environment, known as negative switching behavior. Research by Bermúdez et al. ( 2024 ) and Boycheva Woltering et al. ( 2019 ) indicated that rearing the parasitoid wasps Tetrastichus howardi Olliff (Hymenoptera: Eulophidae) and Trichopria drosophilae Perkins (Hymenoptera: Diapriidae) on alternate hosts did not significantly impact preference for the target pest host. In the T. drosophilae study, however, individuals reared from Drosophila suzukii Matsumura, the target host, had improved oviposition and host preference compared to those raised on Drosophila melanogaster Meigen, which is the alternative, more efficient host for laboratory-rearing. As a result, it was suggested to rear T. drosophilae on D. suzukii for one generation prior to release for enhanced biological control performance (Boycheva Woltering et al. 2019 ). It is clear investigating host switching in parasitoids is imperative to maximize lab-rearing efficiency and biological control outcomes, which may be achieved through life table analyses (Khaki et al. 2022 ). Among the known hosts for P. saccharicola , A. arabicum stands out as a high-quality, easy to rear host (Forouzan et al. 2018 ). However, to ascertain whether A. arabicum is an effective resource for P. saccharicola production and to understand potential costs and benefits associated with host switching, we have undertaken a laboratory experiment to study the effects of host switching on the fitness of P. saccharicola based on a two‑generation approach (Samková et al. 2021 ). For this, our study objectives were to evaluate the female reproductive traits, population growth rates, and life table parameters associated with P. saccharicola reared on A. arabicum and B. germari to determine which is a more suitable host, as well as to identify if switching hosts in a lab setting would be a useful tool in the long term production of this parasitoid. The goal of this work is to ultimately provide a solid foundation for optimizing the mass rearing of P. saccharicola for augmentative biological control programs against its major hosts, Acrosternum arabicum and Brachynema germari . MATERIAL AND METHODS Insect collection and establishment of laboratory colonies Adult individuals of B. germari and A. arabicum were collected from their natural habitats in pistachio orchards (Iran, Kerman, Rafsanjan, Ahmad Abad pistachio orchards, 30°27'31.0"N 55°40'27.9"E) where they were found on understory plants such as Russian thistle, Salsola kali L (Caryophyllales: Amaranthaceae). They were transferred to the laboratory environment and reared on a diet comprised of green beans, sunflower seeds, and peanuts (Pourkhatoon et al. 2016 ). The rearing conditions for both species were maintained at a temperature of 25 ± 1°C, a relative humidity of 50 ± 10%, and a 16:8 hour light-dark cycle. The insects were housed in 28x11x21 cm plastic containers, which were covered with fine mesh. The key by Ribes and Schmitz ( 1992 ) was used for species-level identification. To collect P. saccharicola , freshly laid A. arabicum and B. germari egg masses (≤ 1 day old) were procured from laboratory-reared individuals and glued to yellow cards (7x7 cm). The cards were then situated 50 cm above the ground in pistachio orchards and on Russian thistle bushes ( Salsola kali L.). The cards were retrieved and brought back to the laboratory for observation 48 hours post-installation. After approximately five days eggs were checked for parasitism, which was indicated by the chorion of the eggs turning black in color. Parasitized eggs were maintained under controlled conditions: 25 ± 1°C, 50 ± 10% relative humidity, and a 16:8 hour light-dark cycle, which were upheld until all wasps emerged (Mohammadpour et al. 2016 ). The emerged wasps were housed within 15 ml falcon tubes and were provided sustenance via small droplets of a 90% honey, 10% water solution, which were positioned on paper strips (1x6 cm). The taxonomic keys developed by Johnson and Manser (Johnson and Masner, 1985 ) and Ranjbar et al. ( 2021a ) were used for species-level parasitoid identification. The initial laboratory experiments were carried out using the first generation of wasps collected from the field. Life history parameters of P. saccharicola before and after host-switch To ascertain the average life history parameters of P. saccharicola wasps in our control treatments, which did not undergo host-switch, wasps were segregated into two distinct groups. The first group, the B. germari control treatment, comprised of wasps that had undergone rearing over three successive generations on B. germari eggs. From offspring of the third generation, ten pairs of male and female wasps were selected and transferred to 15 ml Falcon tubes. Each pair was provided with 100 B. germari eggs on a daily basis, supplemented with a 90% honey solution positioned on a 1x6 cm yellow card. This regimen persisted until the expiration of all ten pairs. The same procedure was repeated on the second group, referred to as the A. arabicum control treatment, using wasps that had been reared on A. arabicum eggs across three consecutive generations and providing them with 100 A. arabicum eggs daily. In order to determine the average life history parameters of wasps host-switched from B. germari to A. arabicum , ten male-female pairs of wasps, reared on B. germari for three generations, were individually supplied with 100 A. arabicum eggs accompanied by a 90% honey solution on a daily basis. This treatment is referred to as the first generation of A. arabicum host-switch. This procedure persisted until all ten pairs expired. Another set of ten male-female pairs was isolated upon the emergence of the first generations’ offspring, known as the second generation of A. arabicum host-switch. They were provided with 100 A. arabicum eggs and a 90% honey solution daily, up until the death of all ten pairs. These procedures were repeated, using wasps that have been reared on A. arabicum for three generations and providing them with 100 B. germari eggs daily, to produce data for the first and second generations of B. germari host-switch. For each treatment, lifespan and reproductive traits were recorded for each female wasp. The dates of the first and last egg parasitized by the female wasp were used to determine the length of the oviposition period. The number of eggs parasitized by each female wasp was determined by observing the number of available host eggs that turned black. Biological characteristics of the offspring— developmental time, sex ratio, and survival— were also recorded for each treatment. Development time, the time from initial parasitism to the emergence of an adult wasp, was monitored on a six-hour basis for both female and male wasps. Sex ratio (percent female offspring) was tallied at emergence. Survival was estimated by dividing the number of emerging wasps in each replicate by the total number of parasitized eggs. Life table parameters were also calculated to understand the effect of host and host switching on P. saccharicola population growth. Net reproductive rate, intrinsic rate of increase, finite rate of increase, mean generation time, and population doubling time were calculated using the formulas from Carey ( 1993 ) and ( 2001 ). Data analysis Statistical analysis was conducted with SPSS version 15 software. The homogeneity of variance between treatments was verified using Levine’s test. Moreover, the normality of the data was assessed with the Kolmogorov-Smirnov test. Prior to analysis by one-way ANOVA (α = 0.05), the Arcsin transformation method was applied to normalize offspring production rate and survival rate data, as outlined by Zar and Sabbatini Peverieri et al. (Zar 2010 ; Sabbatini Peverieri et al. 2015 ). Tukey’s test was used to compare the means across various treatments (α = 0.05). Offspring sex ratios, calculated by the total number of females divided by the total number of progeny, were compared among the treatments through a chi-square test (α = 0.05). Life table data were computed using a VBA-macro program in Excel software. The jackknife method (Vantornhout et al. 2005 ) was applied in this calculation. Life table parameters were then compared using Tukey’s test (α = 0.05). RESULTS Female reproductive traits of P. saccharicola reared on B. germari and A. arabicum 1-1- Oviposition period ANOVA results revealed that there were significant differences in oviposition period between treatments (F 2,27 =60.774, P<0.001). The A. arabicum control wasps had a shorter oviposition period compared to the B. germari control (P=0.004), as well as the first generation of wasps host-switched to A. arabicum (P=0.002). Conversely, the oviposition period was longer for the B. germari control compared to the first (P<0.001) and second generations of wasps host-switched to B. germari (P<0.001). However, no difference was found between the B. germari control and the first generation host-switched to A. arabicum (P=0.999). Notably, the first generation of wasps host-switched to B. germari had a shorter oviposition period than the A. arabicum control (P=0.008). The first generation host-switched to A. arabicum had the longest oviposition period (11.5 ± 0.8 days), while the second generation host-switched to B. germari had the shortest oviposition period (1.9 ± 0.3). These results illustrate that the oviposition period decreases significantly when the host switched from A. arabicum to B. germari ( Table 1 ). 1-2- Post-oviposition period ANOVA results showed significant differences in post-oviposition period between treatments (F 2,27 =36.339, P<0.001). Generally, it seemed host switching did not influence the post-oviposition period in the first generation of both species. No differences were observed between the two control treatments (P=0.295), between the A. arabicum control and the first generation host-switched to A. arabicum (P=0.808), or between the B. germari control and the first generation host-switched to B. germari (P=0.650). However, the second generation of wasps host-switched to A. arabicum had a longer post-oviposition period than B. germari (P=0.024) and A. arabicum control treatments (P<0.001), having the longest post-oviposition period (9.7 ± 0.7) of all the treatments ( Table 1 ). 1-3- Female longevity ANOVA results showed significant differences in female longevity between treatments (F 2,27 =143.841, P<0.001). No difference was found between the A. arabicum and B. germari control treatments (P = 0.055). However, differences were observed between the A. arabicum control and the first (P<0.001) and second generations of wasps host-switched to A. arabicum (P=0.003) , showing increased female longevity in the host-switched generations. Conversely, the B. germari control had lower female longevity compared to the first (P<0.001) and second generations host-switched to B. germari (P<0.001). Additionally, the first and second generation of A. arabicum host switch had significantly higher longevity than the B. germari control (P<0.001). In general, it was found that switching the host from B. germari to A. arabicum increases the longevity of females, while switching the host from A. arabicum to B. germari significantly reduces longevity ( Table 1) . 1-4- Total eggs parasitized and eggs parasitized on the first day post-emergence The total number of eggs parasitized during the lifespan of a female wasp, particularly the number of eggs parasitized on the first day post-emergence, are two crucial factors when studying egg parasitoids for biological control (Marchiori, 2022) and when selecting hosts for mass-rearing and release (Conti et al. 2021; Dyck et al. 2021). ANOVA analyses found significant differences in total parasitism (F 2,27 =24.569, P<0.001) and first day parasitism (F 2,27 =15.922, P<0.001) between treatments ( Table 1 ). The total number of eggs parasitized during the wasps' lifetime was higher in the B. germari control compared to the A. arabicum control (P<0.001), and was also higher in the A. arabicum control compared to the first generation of its host switch (P=0.017). Total parasitism was also higher in the B. germari control compared to the first (P<0.001) and second generations host-switched to B. germari (P<0.001). Moreover, the number of eggs parasitized on the first day post-emergence was higher in the A. arabicum control compared to the B. germari control (P<0.001). Also, the number of eggs parasitized on the first day post-emergence was higher in the first generation host-switched to B. germari compared to the B. germari control (P=0.008). This would indicate that rearing parasitoids on A. arabicum would result in the same or increased parasitism by P. saccharicola , while rearing on B. germari would result in reduced parasitism, should host switching occur after release. Daily egg parasitism by P. saccharicola is shown in Fig. 1 and Fig. 2 . Biological characteristics of P. saccharicola reared on A. arabicum and B. germari 2-1- Development time ANOVA analyses showed significant differences in male (F 2,27 =132.771, P<0.001) and female (F 2,27 =97.878, P<0.001) development time between treatments. Post-hoc tests revealed that P. saccharicola males and females in the B. germari control had longer development periods than in the first (male: P<0.001; female: P<0.001) and second generations host-switched to B. germari (male: P=0.048; female: P=0.028). In contrast, the A. arabicum control had shorter development times compared to the first generation host-switched to A. arabicum (male: P<0.001; female: P<0.001). Furthermore, the A. arabicum control had shorter development times than the B. germari control (male: P<0.001; female: P<0.001). Notably, the B. germari control had the longest development time for both males (15.2 ± 0.1 days) and females (16.5 ± 0.2 days), while the A. arabicum control had the shortest female development period (12.7 ± 0.1 days) and the second generation host-switched to A. arabicum had the shortest male development period (11.6 ± 0.2 days, Table 2 ). These results indicated that A. arabicum eggs may be higher quality than B. germari for P. saccharicola rearing, resulting in faster larval growth and development. 2-2- Sex ratio There was a significant difference in the P. saccharicola sex ratio between treatments (F 2,27 =8.565, P<0.001). The A. arabicum control produced a higher ratio of female wasps than the B. germari control (P<0.001). However, no differences were observed between the B. germari control and the first (P=0.245) and second generations host-switched to B. germari (P=0.270). Similarly, no differences were found between the A. arabicum control and the first (P=0.536) and second generations host-switched to A. arabicum (P=0.219). The A. arabicum control had the highest sex ratio, while the B. germari control had the lowest sex ratio ( Table 2 ). 2-3- Survival rate Survival data revealed that the B. germari control (0.857 ± 0.016) had a significantly lower survival rate compared to the A. arabicum control (0.952 ± 0.004, F 2,27 =14.373, P<0.001). No significant differences were found between any other treatments. In general, it seems host switching did not influence survival rate ( Table 2 ). Life table parameters of P. saccharicola reared on B. germari and A. arabicum Statistical results for life table parameters between treatments are presented in Table 3 . 3-1- Net reproductive rate An ANOVA showed significant differences in net reproductive rate (F 2,27 =1139.152, P<0.001). The B. germari control had a higher net reproductive rate than the A. arabicum control (P<0.001). Additionally, the A. arabicum control had a significantly higher reproductive rate compared to the first (P<0.001) and second generations of A. arabicum host-switch (P<0.001). Similarly, the reproductive rate in the B. germari control was higher than in the first (P<0.001) and second generations of wasps host-switched B. germari (P<0.001). The B. germari control has the highest net reproductive rate (117.24 ± 0.4), indicating that using B. germari eggs as hosts would produce more females. Notably, the second generation of B. germari host-switch has the lowest net reproductive rate, significantly lower than all other treatments (81.1 ± 0.2). 3-2- Intrinsic rate of increase ANOVA results showed differences in intrinsic rate of increase between treatments (F 2,27 = 223.281, P = 0.000). While the net reproduction rate was highest in the B. germari control, it was found that the intrinsic rate of increase in the A. arabicum control (0.323 ± 0.001) was higher compared to the B. germari control (P = 0.000). The lowest intrinsic rates of increase were recorded for B. germari control (0.250 ± 0.001) and the second generation of wasps host-switched to B. germari control (0.251± 0.001), with a significant difference compared to the other treatments ( Table 3 ). Additionally, significant differences were observed between the A. arabicum control and the first (P<0.001) and second generations of wasps host-switched to A. arabicum (P<0.001). However, for B. germari treatments, a significant difference was observed only between the first generation host-switched to B. germari and the B. germari control (P<0.001). Results illustrated when wasps host-switched from B. germari to A. arabicum the intrinsic rate of increase declined significantly in comparison to the A. arabicum control, however the reverse occurred when host switching from A. arabicum to B. germari compared to the B. germari control, at least in the first generation. 3-3- Finite rate of increase ANOVA results revealed differences in the finite rate of increase between treatments (F 2,27 = 232.317, P<0.001). As predicted based on the intrinsic rate of increase, the A. arabicum control had a greater finite rate of increase compared to the B. germari control (P<0.001). Furthermore, the finite rate of increase for the A. arabicum control was higher compared to the first (P<0.001) and second generations host-switched to A. arabicum (P<0.001). This shows that the wasp population developed more slowly when switched from B. germari to A. arabicum in comparison to the control treatments. The finite rate of increase in the B. germari control was less than first generation of wasps switched to B. germari (P<0.001). However, no difference was observed between the B. germari control and the second generation host-switch (P=1.000). Notably, the A. arabicum control had the highest finite population increase rate (1.382 ± 0.001), while the second generation wasps host-switched to B. germari (1.285 ± 0.001) and the B. germari control treatment (1.285 ± 0.002), had the lowest finite population increase rate. 3-4- Mean generation time ANOVA analysis showed significant differences in generation time between treatments (F 2,27 =85908.824, P<0.001), with following post-hoc tests finding all treatments different from each other P<0.001). Interestingly, switching the host from A. arabicum to B. germari significantly decreased the mean generation time compared to the B. germari control (P<0.001). The A. arabicum control treatment has the shortest mean generation time (14.14 ± 0.003 days), followed by the second generation host-switched to A. arabicum (14.96 ± 0.006). In contrast, the B. germari control treatment had the longest average mean generation time (18.685 ± 0.006), followed by the second generation host-switched to B. germari (17.373± 0.004). 3-5- Population doubling time ANOVA analysis revealed significant differences in population doubling time (DT) F 2,27 =166.440, P<0.001). The A. arabicum control had a much lower than the B. germari control (P<0.001). The A. arabicum control had the shortest DT (2.149 ± 0.006), while the B. germari control has the longest DT (2.768 ± 0.10, P<0.001). Moreover, these results showed that when wasps were host-switched from A. arabicum to B. germari the DT increased dramatically. Notably, there was no statistically significant difference between the B. germari control treatment and the second generation host-switched to B. germari (P=1.000). DISCUSSION One of the most important factors affecting the performance of a parasitoid biological control agent is its host (Huffaker and Messenger 1976 ; Henry et al. 2010 ). Looking at the impact of different host species on parasitoid fitness is imperative for determining the suitability of a host for rearing. Of the life table parameters examined in this study, intrinsic rate of increase, or net growth of a population, is an especially vital index for mass-rearing. This factor can be used to compare the effect of rearing conditions on parasitoid population growth, thus allowing for the determination of the most efficient rearing protocols as well as estimating success of establishment upon release (Bigler 1989 ; Chi 1990 ; Strong and Pemberton 2000 ). Our study revealed that, among the experimental treatments, the A. arabicum control group exhibited the highest rate of population increase in P. saccharicola .In general, our findings indicated that rearing P. saccharicola on A. arabicum is more efficient than rearing on B. germari , as A. arabicum eggs resulted in more progeny, a faster development time, and a higher female-to-male sex ratio (Table 2 ). This study illustrates that P. saccharicola development and reproduction is affected by host species. Future research may provide information on the mechanisms behind the observed differences in parasitoid fitness, allowing for the development of more efficient rearing protocols. Differences in host suitability have been attributed to phylogenetic relationships between the host species and similarities/ differences in kairomones in other parasitoid-host systems (Drost and Carde 1992). Additionally, research has linked the reproductive rate, finite rate of increase and survival rate of progeny to the percentage of compounds and proportion of nutrients in the host's body (Bourchier et al. 1994 ; Rakhshani et al. 2004 ; Jones et al. 2015 ). Previous studies found that A. arabicum and B. germari have high density populations in pistachio orchards during the growing season (Hashemi Rad 2009 ; Mehrnejad et al. 2013 ). Since the P. saccharicola laboratory populations used in this study were established with individuals collected from pistachio orchards it can be surmised that this wasp co-evolved with both species. However, it has also been reported that B. germari is migratory and spends winter in the hills and mountains, while A. arabicum generally overwinters in the same area of pistachio orchards (Hashemi Rad 2009 ; Mehrnejad et al. 2013 ). The results suggest that the P. saccharicola wasp population had greater compatibility with A. arabicum . Should P. saccharicola overwinter in the orchards with A. arabicum , this may explain the increased compatibility between these two species. During our collections we did not detect P. saccharicola outside of pistachio orchards, however further investigations into their overwintering behavior may shed light on their host preferences. Based on the finite rates of increase found in this study,, where λ was found to be greater than 1 in all treatments, rearing P. saccharicola on either host would lead to an increase in the total wasp population. This holds true for wasps that stay on the same host they are reared on, as well as wasps that host-switch in the lab or potentially after release into the environment. It was observed that switching the host from A. arabicum to B. germari results in a significant decrease in doubling time in the first generation of host-switch. This suggests that using A. arabicum as a host enables P. saccharicola populations to grow quickly, resulting in efficient lab-rearing and ultimately achieving pest control in a shorter period of time. Based on these results and intrinsic rates of increase, we conclude that A. arabicum is the most suitable host for mass-rearing P. saccharicola . Due to declines in parasitoid fitness resulting from lab rearing on a single host, it is important to determine the impact of switching to another suitable host on parasitoid performance. When a biological control agent is reared on one host and then switched to another, a decrease in life table parameters, especially the finite rate of increase, may indicate that mass-rearing on a host could negatively impact the parasitoid's fitness and adaptability once released into the environment. However, if these parameters increase or remain unchanged after host switching it may be hoped that lab-reared parasitoids will be reproductively successful, resulting in effective biological control. In another parasitoid-host system, a host switching test was conducted on the parasitoid Spalangia endius Walker and two economically significant pest flies, Bactrocera dorsalis Hendel and Musca domestica L. It was observed that the performance of S. endius gradually declined after being reared on M. domestica for 50 consecutive generations (Zheng et al. 2021 ). However, after a single generation of host-switch to B. dorsalis , the wasp's performance returned to its original level. In the previously mentioned T. drosophilae system, parasitism performance could be enhanced by rearing on D. suzukii before release, after continuous rearing on the host D. melanogaster (Boycheva Woltering et al. 2019 ). Therefore, it is suggested that the use of alternative hosts and host switching is essential for the successful and long-term rearing of the parasitoids. By investigating the impacts of host-switching over two generations, we could observe how long it would take for parasitoid performance to recover after a host-switch. In the current study, P. saccharicola was found to oviposit on eggs of both hosts, A. arabicum and B. germari . Generally, there is little difference in the wasp’s ability to effectively parasitize these two hosts, as the wasp's performance in the second generation after a host-switch resembles that of the control generation. This suggests that if a decline in performance occurs after several generations reared on the A. arabicum , it is likely that this decline can be mitigated by a single host-switch, restoring the wasp's performance to its maximum after two generations of rearing on a new host such as B. germari . To implement augmentative biological control successfully, rearing protocols must be streamlined to produce biological control agents as quickly and cost-effectively as possible. As our study has shown, finding the most efficient host for rearing parasitoids with multiple hosts and determining the effects of host switching on reproduction is necessary for a practical rearing operation and successful releases. To build off these laboratory findings, complementary field studies are critical to predict if P. saccharicola will significantly impact pentatomid populations and if lab-reared individuals will be successful biological control agents. Potential studies may include long-term surveys to determine the current pest densities of A. arabicum and B. germari as well as in-field parasitism rates for P. saccharicola . Other factors that should be further explored include P. saccharicola host-range studies and the presence of other hosts in pistachio orchards. Further work may be done to evaluate the success of these lab reared individuals in finding hosts and reproducing in the field. It is also important to note that while the results of this study have implications for how P. saccharicola will fare after release into the environment, exposure to other potential hosts and variable field conditions may impact population growth. This information will ultimately be essential to the implementation of a rearing program for P. saccharicola and will allow for more sustainable pest control in pistachio orchards. We conclude that mass production of P. saccharicola for augmentation in pistachio orchards can be safely carried out using eggs of A. arabicum , which are more easily and cost-effectively produced than eggs of B. germari , without any significant negative consequences for their fitness or performance on the more suitable host. However, release rates should take into account the fact that most stink bug egg masses will not be fully parasitized by a single wasp encounter due to the observed egg load constraints. Declarations The authors have no competing interests to declare that are relevant to the content of this article. Data availability statements All data supporting the findings of this study are available within the paper. Author Contribution Abbas Esmaeili Sardary: Conceptualization, data collection, writing original draft. Fatemeh Ranjbar: Conceptualization, experimental design, data analysis. Sabrina L. Celis: Results interpretation, writing and editing. M. Amin Jalali: Supervision, conceptualization, experimental design, methodology. Mahdi Ziaaddini: Visualization, methodology. Acknowledgement The authors are grateful to Vali-e-Asr University of Rafsanjan, Iran, for financial support to AES. (MS student no. 99124006). This work was funded, in part, by the Biotechnology Development Council of the Islamic Republic of Iran, Grant No: biodc-2002275-2002140.1. References Abram PK, Mills NJ, Beers EH (2020) Review: classical biological control of invasive stink bugs with egg parasitoids – what does success look like? Pest Manag Sci 76: 1980-1992 https://doi.org/10.1002/ps.5813 Bermúdez NC, de la Pava N, Cáceres JSD, da Silva-Torres CSA, Torres JB (2024) Long-term suitability of an alternative host for rearing the sugarcane stalk borer parasitoid Tetrastichus howardi . Bull Entom Res 2024:1-12 https://doi.org/doi:10.1017/S0007485324000129 Bigler F (1989) Quality assessment and control in entomophagous insects used for biological control. J Appl Entomol 108: 390-400 https://doi.org/10.1111/j.1439-0418.1989.tb00473.x Bourchier RS, Smith SM, Corrigan JE, Laing JE (1994) Effect of host switching on performance of mass reared Trichogramma minutum . 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Pearson Prentice-Hall, Upper Saddle River, NJ Zheng Y, Song ZW, Zhang YP, Li DS (2021) Ability of Spalangia endius (Hymenoptera: Pteromalidae) to parasitize Bactrocera dorsalis (Diptera: Tephritidae) after switching hosts. Insects 12 (7): 613 https://doi.org/10.3390/insects12070613 Zheng Z, Saghaian SH, Reed MR (2012) Factors affecting the export demand for US pistachios. International Food and Agribusiness Management Review 15: 139-154 http://dx.doi.org/10.22004/ag.econ.133490 Tables Table 1. Mean (± SE) number of females observed (n), oviposition period ( OP ), post oviposition period ( POP ), female longevity ( FL ), total number of eggs parasitized ( TP ), and number of eggs parasitized in the first day ( N 1st ) for psix saccharicola reared on Acrosternum arabicum and Brachynema germari in the no-switch controls, and the first and second host-switched generations. The averages displayed with the same letters in each column are not significantly different from each other (Tukey HSD test, α = 0.05). Host Treatment n a OP (days) POP (days) FL (days) TP N 1st Control 11 8.727b (±0.384) 4.091cd (±0.436) 12.818c (±0.263) 112.910b (±1.246) 83.0910a (±1.528) Acrosternum arabicum 1st generation switch 9 11.556a (±0.835) 5.000c (±0.898) 16.556a (±0.176) 95.222c (±7.794) 53.889d (±5.059) 2nd generation switch 10 4.600c (±0.718) 9.700a (±0.716) 14.300b (±0.367) 101.700bc (±2.708) 70.900bc (±2.297) Control 10 11.300a (±0.213) 2.600de (±0.305) 13.900bc (±0.233) 144.300a (±3.916) 62.900cd (±3.035) Brachynema germari 1st generation switch 10 6.300c (±0.213) 1.500e (±0.167) 7.800e (±0.133) 112.300b (±2.499) 76.500ab (±1.232) 2nd generation switch 10 1.900e (±0.277) 7.500b (±0.224) 9.400d (±0.340) 94.900c (±1.670) 62.500cd (±1.759) Table 2. Mean (± SE) development times of females (female) and males (male), progeny sex ratio (sex ratio) and progeny survival (survival) for psix saccharicola reared on Acrosternum arabicum and Brachynema germari in the no-switch controls, and the first and second host-switched generations. The averages displayed with the same letters in each column are not significantly different from each other (Tukey HSD test, α = 0.05). * Is the number of females' offsprings which observed. Host Treatment Development time (day) Sex ratio (%) Survival (%) Female Male Control 12.734±0.118d (15)* 11.400±0.131e (15) 0.929±0.004a (11) 0.952±0.004a (11) Acrosternum arabicum 1st generation switch 14.400±0.163c (10) 13.000±0.000d (10) 0.912±0.012ab (9) 0.882±0.012cb (9) 2nd generation switch 13.300±0.153d (10) 11.600±0.163e (10) 0.909±0.006ab (10) 0.913±0.007b (10) Control 16.500±0.167a (10) 15.200±0.134a (10) 0.871±0.010c (10) 0.857±0.016c (10) Brachynema germari 1st generation switch 14.900±0.180c (10) 13.700±0.153c (10) 0.895±0.005bc (10) 0.913±0.004b (10) 2nd generation switch 15.800±0.134b (10) 14.600±0.163b (10) 0.894±0.006bc (10) 0.917±0.006b (10) Table 3. Mean (± SE) number of females observed (n), net reproductive rate ( R o ), intrinsic rate of increase ( r m ), finite rate of increase ( λ ), mean generation time ( T ), and doubling time ( DT ) for psix saccharicola reared on Acrosternum arabicum and Brachynema germari in the no-switch controls, and the first and second host-switched generations. The averages displayed with the same letters in each column are not significantly different from each other (Tukey HSD test, α = 0.05). Life table parameters Host Treatment n R o (females/female) r m (females/female/day) λ (females/female/day) T (days) DT (days) Control 11 95.643b (±0.106) 0.323a (±0.001) 1.381a (±0.001) 14.140f (±0.003) 2.149e (±0.006) Acrosternum arabicum 1st generation switch 9 76.123f (±0.779) 0.262d (±0.005) 1.299d (±0.006) 16.578c (±0.010) 2.657b (±0.045) 2 nd generation switch 10 84.338d (±0.250) 0.300b (±0.0001) 1.345b (±0.002) 14.955e (±0.006) 2.338d (±0.011) Control 10 107.733a (±0.325) 0.250e (±0.001) 1.285e (±0.001) 18.685a (±0.006) 2.768a (±0.013) Brachynema germari 1st generation switch 10 91.744c (±0.227) 0.277c (±0.001) 1.319c (±0.001) 16.335d (±0.003) 2.506c (±0.010) 2 nd generation switch 10 77.776e (±0.152) 0.251e (±0.001) 1.285e (±0.001) 17.373b (±0.004) 2.766a (±0.010) Additional Declarations No competing interests reported. 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Amin Jalali","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA1UlEQVRIie3QMQrCMBTG8U8C6fLUtaLYEwgvFDr2LIGAk4Oj4GBB0MUb6GEqhboIro51d3NxcDCKg1ONm2D+0wvkRx4BfL4fjTFGTwbZ6yicCIMk5V+QByKE2nGpwTLH+MoptTrn5EJIIwTNqpYkew21YkOyO4rXBKMyEXA9yTWYWFgyNIIgNISsXyw5VFA3npHslA8ycyBHjZi4IBmKwpLChZyyuMc7+8mmaGx4pxafFzOlOk+m/Wi5ncMOUbtd1hOgsXj7IDt+eOOZqBwu+Xw+3z93B61LL/aRPbvYAAAAAElFTkSuQmCC","orcid":"","institution":"Vali-e-Asr University of Rafsanjan","correspondingAuthor":true,"prefix":"","firstName":"M.","middleName":"Amin","lastName":"Jalali","suffix":""},{"id":383789703,"identity":"5115dfaf-2fc5-446a-bc2d-6765feec7e10","order_by":4,"name":"Mahdi Ziaaddini","email":"","orcid":"","institution":"Vali-e-Asr University of Rafsanjan","correspondingAuthor":false,"prefix":"","firstName":"Mahdi","middleName":"","lastName":"Ziaaddini","suffix":""}],"badges":[],"createdAt":"2024-10-01 08:08:31","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5185542/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5185542/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":71529656,"identity":"034a6a7a-f3ea-444f-b52f-4bdac267942e","added_by":"auto","created_at":"2024-12-16 13:05:20","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":168860,"visible":true,"origin":"","legend":"\u003cp\u003eDaily egg parasitism by \u003cem\u003ePsix saccharicola\u003c/em\u003e reared on \u003cem\u003eAcrosternum arabicum\u003c/em\u003e in the control treatment (dark grey diamond), the first (light grey square) and the second (gray triangle) generation of the host-switch from \u003cem\u003eBrachynema germari\u003c/em\u003e to \u003cem\u003eA. arabicum\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-5185542/v1/ed2a2c50df001ee6cb123b53.png"},{"id":71529655,"identity":"861ad45f-6348-4e08-9bbd-b7bf9ef743d1","added_by":"auto","created_at":"2024-12-16 13:05:20","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":177980,"visible":true,"origin":"","legend":"\u003cp\u003eDaily egg parasitism by \u003cem\u003ePsix saccharicola\u003c/em\u003e reared on \u003cem\u003eBrachynema germari\u003c/em\u003e in the control treatment (dark grey diamond), and the first (light grey square) and the second (grey triangle) generation of the host-switch from \u003cem\u003eAcrosternum arabicum\u003c/em\u003e to \u003cem\u003eB. germari\u003c/em\u003e\u003c/p\u003e","description":"","filename":"Fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-5185542/v1/725df46a3b776bb3be8f31ef.png"},{"id":71530982,"identity":"3ee61afa-d516-4fd9-a405-9227cbcd196b","added_by":"auto","created_at":"2024-12-16 13:13:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":994733,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5185542/v1/c86085d1-29a7-446a-9456-e25aee26d803.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Fitness consequences of host switching by Psix saccharicola, a stink bug egg parasitoid in pistachio orchards","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003ePistachio (\u003cem\u003ePistachio vera\u003c/em\u003e L.) is a significant commercial nut in Iran, the world\u0026rsquo;s top producer and exporter, prompting meticulous study of its pests and management options (Pakravan and Kavoosi-Kalashami 2011; Zheng et al. \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Stink bugs in the family Pentatomidae are among the predominant pests inflicting damage to pistachio trees. This group of insects, comprised of invasive species as well as emerging native pests, is assuming a pivotal role as pests on a variety of crop plants (Mehrnejad \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). \u003cem\u003eAcrosternum arabicum\u003c/em\u003e Wagner (Hemiptera: Pentatomidae) and \u003cem\u003eBrachynema germari\u003c/em\u003e Kolenati (Hemiptera: Pentatomidae) are two native, economically significant species, and are the two most abundant pentatomid species found in Iranian pistachio orchards. These pests pose substantial challenges to growers due to their broad host range, long-term pest activity spanning from initial floral growth to post-harvest storage, and their potential to transmit pathogens (Mehrnejad \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2001\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eDirect feeding on immature pistachio nuts by stink bugs can lead to dropped nut clusters, discoloration, deformation, and even the abortion of fruiting structures. As shells harden, feeding can cause necrosis and impart a bitter taste to the nut. Feeding may also result in indirect consequences such as transmission of the fungal pathogen \u003cem\u003eEremothecium coryli\u003c/em\u003e Kurtzman, causing stigmatomycosis. This results in foul-smelling, slimy nuts that are unfit for sale (Ershad and Barkhordary \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1974\u003c/span\u003e). If stink bug population reaches injury levels of more than two female adults per 100 tree branches, these pests have the potential to damage over 60% of the orchard\u0026rsquo;s pistachio yield. Chemical insecticides, like organophosphates and pyriproxyfen, have been utilized to combat these pests (Mehrnejad et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Mehrnejad \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Mehrnejad \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eBiological control strategies seem to be promising alternatives for pentatomid control, protecting crop quality and quantity while reducing the need for pesticide applications (Ershad and Barkhordary \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1974\u003c/span\u003e; Uyemoto et al. \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e1986\u003c/span\u003e; Ferguson and Haviland \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Egg parasitoid wasps are dominant biological control agents in stink bug pest management, with many species currently being studied (Abram et al. \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Conti et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Two decades of parasitoid surveys in pistachio orchards documented ten wasps in the families Encyrtidae and Scelionidae that actively parasitize \u003cem\u003eA. arabicum\u003c/em\u003e and \u003cem\u003eB. germari\u003c/em\u003e eggs. \u003cem\u003ePsix saccharicola\u003c/em\u003e Mani (Hymenoptera: Scelionidae) was one of the most dominant egg parasitoids in this survey due to its high female-to-male sex-ratio and parasitism rate, and as a result it has been identified as a potential biological control agent (Orr \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e1988\u003c/span\u003e; Ranjbar et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2021a\u003c/span\u003e; Ranjbar et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2021b\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eTo develop a program for the mass-release of \u003cem\u003eP. saccharicola\u003c/em\u003e in pistachio orchards, it is important to determine the most efficient host for rearing. Host switching can be used to evaluate the impact of a potential host species on parasitoid fitness in comparison to other hosts (Cornell and Pimentel \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1978\u003c/span\u003e). During the host switching tests by Cornell and Pimentel (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1978\u003c/span\u003e), a remarkable revelation emerged: while one host might be convenient and efficient for rearing, transferring the parasitoid's offspring to another host can lead to a substantial reduction in parasitism rate. Additionally, the use of an alternative host could influence development time and body size, both of which impact female fecundity (Smith et al. \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e1995\u003c/span\u003e). On a contrasting note, plasticity in parasitoid behavior when encountering a new host may result in net population growth even if other factors affecting reproduction, such as oviposition rate, are negatively impacted (Bourchier et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Dyck et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). This is important to consider when rearing biological control agents, especially those used to control a different species than what they are reared on, or multiple species as in the case of \u003cem\u003eP. saccharicola.\u003c/em\u003e Also, while rearing on a single host may be sufficient in some cases, concerns arise regarding parasitoid fitness when it is reared on the same host for more than three generations in laboratory conditions (Bigler \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1989\u003c/span\u003e; Bourchier et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Samkov\u0026aacute; et al. \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Consequently, host switching tests are indispensable to ensure the viability of long-term parasitoid rearing and to assess the indirect risks associated with mass parasitoid releases (Chow and Mackauer \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e1991\u003c/span\u003e; Drost and Carde 1992; Fowler et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eRecently, there have been extensive studies on host switching in parasitoids and how the use of multiple hosts may impact production as well as biological control efficacy. In Ghaemmaghami et al. (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2023\u003c/span\u003e), researchers found that rearing a parasitoid on one host resulted in a lower functional response to another host, even when the alternative host is more readily available in the environment, known as negative switching behavior. Research by Berm\u0026uacute;dez et al. (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2024\u003c/span\u003e) and Boycheva Woltering et al. (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) indicated that rearing the parasitoid wasps \u003cem\u003eTetrastichus howardi\u003c/em\u003e Olliff (Hymenoptera: Eulophidae) and \u003cem\u003eTrichopria drosophilae\u003c/em\u003e Perkins (Hymenoptera: Diapriidae) on alternate hosts did not significantly impact preference for the target pest host. In the \u003cem\u003eT. drosophilae\u003c/em\u003e study, however, individuals reared from \u003cem\u003eDrosophila suzukii\u003c/em\u003e Matsumura, the target host, had improved oviposition and host preference compared to those raised on \u003cem\u003eDrosophila melanogaster\u003c/em\u003e Meigen, which is the alternative, more efficient host for laboratory-rearing. As a result, it was suggested to rear \u003cem\u003eT. drosophilae\u003c/em\u003e on \u003cem\u003eD. suzukii\u003c/em\u003e for one generation prior to release for enhanced biological control performance (Boycheva Woltering et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). It is clear investigating host switching in parasitoids is imperative to maximize lab-rearing efficiency and biological control outcomes, which may be achieved through life table analyses (Khaki et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAmong the known hosts for \u003cem\u003eP. saccharicola\u003c/em\u003e, \u003cem\u003eA. arabicum\u003c/em\u003e stands out as a high-quality, easy to rear host (Forouzan et al. \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). However, to ascertain whether \u003cem\u003eA. arabicum\u003c/em\u003e is an effective resource for \u003cem\u003eP. saccharicola\u003c/em\u003e production and to understand potential costs and benefits associated with host switching, we have undertaken a laboratory experiment to study the effects of host switching on the fitness of \u003cem\u003eP. saccharicola\u003c/em\u003e based on a two‑generation approach (Samkov\u0026aacute; et al. \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). For this, our study objectives were to evaluate the female reproductive traits, population growth rates, and life table parameters associated with \u003cem\u003eP. saccharicola\u003c/em\u003e reared on \u003cem\u003eA. arabicum\u003c/em\u003e and \u003cem\u003eB. germari\u003c/em\u003e to determine which is a more suitable host, as well as to identify if switching hosts in a lab setting would be a useful tool in the long term production of this parasitoid. The goal of this work is to ultimately provide a solid foundation for optimizing the mass rearing of \u003cem\u003eP. saccharicola\u003c/em\u003e for augmentative biological control programs against its major hosts, \u003cem\u003eAcrosternum arabicum\u003c/em\u003e and \u003cem\u003eBrachynema germari\u003c/em\u003e.\u003c/p\u003e"},{"header":"MATERIAL AND METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eInsect collection and establishment of laboratory colonies\u003c/h2\u003e \u003cp\u003eAdult individuals of \u003cem\u003eB. germari\u003c/em\u003e and \u003cem\u003eA. arabicum\u003c/em\u003e were collected from their natural habitats in pistachio orchards (Iran, Kerman, Rafsanjan, Ahmad Abad pistachio orchards, 30\u0026deg;27'31.0\"N 55\u0026deg;40'27.9\"E) where they were found on understory plants such as Russian thistle, \u003cem\u003eSalsola kali\u003c/em\u003e L (Caryophyllales: Amaranthaceae). They were transferred to the laboratory environment and reared on a diet comprised of green beans, sunflower seeds, and peanuts (Pourkhatoon et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). The rearing conditions for both species were maintained at a temperature of 25\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u0026deg;C, a relative humidity of 50\u0026thinsp;\u0026plusmn;\u0026thinsp;10%, and a 16:8 hour light-dark cycle. The insects were housed in 28x11x21 cm plastic containers, which were covered with fine mesh. The key by Ribes and Schmitz (\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e1992\u003c/span\u003e) was used for species-level identification.\u003c/p\u003e \u003cp\u003eTo collect \u003cspan type=\"ItalicUnderline\" class=\"ItalicUnderline\" name=\"Emphasis\"\u003eP. saccharicola\u003c/span\u003e, freshly laid \u003cem\u003eA. arabicum\u003c/em\u003e and \u003cem\u003eB. germari\u003c/em\u003e egg masses (\u0026le;\u0026thinsp;1 day old) were procured from laboratory-reared individuals and glued to yellow cards (7x7 cm). The cards were then situated 50 cm above the ground in pistachio orchards and on Russian thistle bushes (\u003cem\u003eSalsola kali\u003c/em\u003e L.). The cards were retrieved and brought back to the laboratory for observation 48 hours post-installation. After approximately five days eggs were checked for parasitism, which was indicated by the chorion of the eggs turning black in color. Parasitized eggs were maintained under controlled conditions: 25\u0026thinsp;\u0026plusmn;\u0026thinsp;1\u0026deg;C, 50\u0026thinsp;\u0026plusmn;\u0026thinsp;10% relative humidity, and a 16:8 hour light-dark cycle, which were upheld until all wasps emerged (Mohammadpour et al. \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe emerged wasps were housed within 15 ml falcon tubes and were provided sustenance via small droplets of a 90% honey, 10% water solution, which were positioned on paper strips (1x6 cm). The taxonomic keys developed by Johnson and Manser (Johnson and Masner, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e1985\u003c/span\u003e) and Ranjbar et al. (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2021a\u003c/span\u003e) were used for species-level parasitoid identification. The initial laboratory experiments were carried out using the first generation of wasps collected from the field.\u003c/p\u003e \u003cp\u003e \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eLife history parameters of\u003c/span\u003e \u003cspan type=\"ItalicUnderline\" class=\"ItalicUnderline\" name=\"Emphasis\"\u003eP. saccharicola\u003c/span\u003e \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003ebefore and after host-switch\u003c/span\u003e\u003c/p\u003e \u003cp\u003eTo ascertain the average life history parameters of \u003cem\u003eP. saccharicola\u003c/em\u003e wasps in our control treatments, which did not undergo host-switch, wasps were segregated into two distinct groups. The first group, the \u003cem\u003eB. germari\u003c/em\u003e control treatment, comprised of wasps that had undergone rearing over three successive generations on \u003cem\u003eB. germari\u003c/em\u003e eggs. From offspring of the third generation, ten pairs of male and female wasps were selected and transferred to 15 ml Falcon tubes. Each pair was provided with 100 \u003cem\u003eB. germari\u003c/em\u003e eggs on a daily basis, supplemented with a 90% honey solution positioned on a 1x6 cm yellow card. This regimen persisted until the expiration of all ten pairs. The same procedure was repeated on the second group, referred to as the \u003cem\u003eA. arabicum\u003c/em\u003e control treatment, using wasps that had been reared on \u003cem\u003eA. arabicum\u003c/em\u003e eggs across three consecutive generations and providing them with 100 \u003cem\u003eA. arabicum\u003c/em\u003e eggs daily.\u003c/p\u003e \u003cp\u003eIn order to determine the average life history parameters of wasps host-switched from \u003cem\u003eB. germari\u003c/em\u003e to \u003cem\u003eA. arabicum\u003c/em\u003e, ten male-female pairs of wasps, reared on \u003cem\u003eB. germari\u003c/em\u003e for three generations, were individually supplied with 100 \u003cem\u003eA. arabicum\u003c/em\u003e eggs accompanied by a 90% honey solution on a daily basis. This treatment is referred to as the first generation of \u003cem\u003eA. arabicum\u003c/em\u003e host-switch. This procedure persisted until all ten pairs expired. Another set of ten male-female pairs was isolated upon the emergence of the first generations\u0026rsquo; offspring, known as the second generation of \u003cem\u003eA. arabicum\u003c/em\u003e host-switch. They were provided with 100 \u003cem\u003eA. arabicum\u003c/em\u003e eggs and a 90% honey solution daily, up until the death of all ten pairs. These procedures were repeated, using wasps that have been reared on \u003cem\u003eA. arabicum\u003c/em\u003e for three generations and providing them with 100 \u003cem\u003eB. germari\u003c/em\u003e eggs daily, to produce data for the first and second generations of \u003cem\u003eB. germari\u003c/em\u003e host-switch.\u003c/p\u003e \u003cp\u003eFor each treatment, lifespan and reproductive traits were recorded for each female wasp. The dates of the first and last egg parasitized by the female wasp were used to determine the length of the oviposition period. The number of eggs parasitized by each female wasp was determined by observing the number of available host eggs that turned black. Biological characteristics of the offspring\u0026mdash; developmental time, sex ratio, and survival\u0026mdash; were also recorded for each treatment. Development time, the time from initial parasitism to the emergence of an adult wasp, was monitored on a six-hour basis for both female and male wasps. Sex ratio (percent female offspring) was tallied at emergence. Survival was estimated by dividing the number of emerging wasps in each replicate by the total number of parasitized eggs. Life table parameters were also calculated to understand the effect of host and host switching on \u003cem\u003eP. saccharicola\u003c/em\u003e population growth. Net reproductive rate, intrinsic rate of increase, finite rate of increase, mean generation time, and population doubling time were calculated using the formulas from Carey (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1993\u003c/span\u003e) and (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2001\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eData analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis was conducted with SPSS version 15 software. The homogeneity of variance between treatments was verified using Levine\u0026rsquo;s test. Moreover, the normality of the data was assessed with the Kolmogorov-Smirnov test. Prior to analysis by one-way ANOVA (α\u0026thinsp;=\u0026thinsp;0.05), the Arcsin transformation method was applied to normalize offspring production rate and survival rate data, as outlined by Zar and Sabbatini Peverieri et al. (Zar \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Sabbatini Peverieri et al. \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Tukey\u0026rsquo;s test was used to compare the means across various treatments (α\u0026thinsp;=\u0026thinsp;0.05). Offspring sex ratios, calculated by the total number of females divided by the total number of progeny, were compared among the treatments through a chi-square test (α\u0026thinsp;=\u0026thinsp;0.05). Life table data were computed using a VBA-macro program in Excel software. The jackknife method (Vantornhout et al. \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2005\u003c/span\u003e) was applied in this calculation. Life table parameters were then compared using Tukey\u0026rsquo;s test (α\u0026thinsp;=\u0026thinsp;0.05).\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cp\u003e\u003cu\u003eFemale reproductive traits of \u003cem\u003eP. saccharicola\u003c/em\u003e reared on \u003cem\u003eB. germari\u003c/em\u003e and \u003cem\u003eA. arabicum\u003c/em\u003e\u0026nbsp;\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e1-1- Oviposition period\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eANOVA results revealed that there were significant differences in oviposition period between treatments (F\u003csub\u003e2,27\u003c/sub\u003e=60.774, P\u0026lt;0.001). The \u003cem\u003eA. arabicum\u003c/em\u003e control wasps had a shorter oviposition period compared to the \u003cem\u003eB. germari\u003c/em\u003e control (P=0.004), as well as the first generation of wasps host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e (P=0.002). Conversely, the oviposition period was longer for the \u003cem\u003eB. germari\u003c/em\u003e control compared to the first (P\u0026lt;0.001) and second generations of wasps host-switched to \u003cem\u003eB. germari\u003c/em\u003e (P\u0026lt;0.001). However, no difference was found between the \u003cem\u003eB. germari\u003c/em\u003e control and the first generation host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e (P=0.999). Notably, the first generation of wasps host-switched to \u003cem\u003eB. germari\u003c/em\u003e had a shorter oviposition period than the \u003cem\u003eA. arabicum\u003c/em\u003e control (P=0.008). The first generation host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e had the longest oviposition period (11.5 \u0026plusmn; 0.8 days), while the second generation host-switched to \u003cem\u003eB. germari\u003c/em\u003e had the shortest oviposition period (1.9 \u0026plusmn; 0.3). These results illustrate that the oviposition period decreases significantly when the host switched from \u003cem\u003eA. arabicum\u003c/em\u003e to \u003cem\u003eB. germari\u003c/em\u003e (\u003cstrong\u003eTable 1\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e1-2- Post-oviposition period\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eANOVA results showed significant differences in post-oviposition period between treatments (F\u003csub\u003e2,27\u003c/sub\u003e=36.339, P\u0026lt;0.001). Generally, it seemed host switching did not influence the post-oviposition period in the first generation of both species. No differences were observed between the two control treatments (P=0.295), between the \u003cem\u003eA. arabicum\u003c/em\u003e control and the first generation host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e (P=0.808), or between the \u003cem\u003eB. germari\u003c/em\u003e control and the first generation host-switched to \u003cem\u003eB. germari\u003c/em\u003e (P=0.650). However, the second generation of wasps host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e had a longer post-oviposition period than \u003cem\u003eB. germari\u003c/em\u003e (P=0.024) and \u003cem\u003eA. arabicum\u003c/em\u003e control treatments (P\u0026lt;0.001), having the longest post-oviposition period (9.7 \u0026plusmn; 0.7) of all the treatments (\u003cstrong\u003eTable 1\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e1-3- Female longevity\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eANOVA results showed significant differences in female longevity between treatments (F\u003csub\u003e2,27\u003c/sub\u003e=143.841, P\u0026lt;0.001). No difference was found between the \u003cem\u003eA. arabicum\u003c/em\u003e and \u003cem\u003eB. germari\u003c/em\u003e control treatments (P = 0.055). However, differences were observed between the \u003cem\u003eA. arabicum\u003c/em\u003e control and the first (P\u0026lt;0.001) and second generations of wasps host-switched to \u003cem\u003eA. arabicum\u0026nbsp;\u003c/em\u003e(P=0.003)\u003cem\u003e,\u003c/em\u003e showing increased female longevity in the host-switched generations. Conversely, the \u003cem\u003eB. germari\u003c/em\u003e control had lower female longevity compared to the first (P\u0026lt;0.001) and second generations host-switched to \u003cem\u003eB. germari\u003c/em\u003e (P\u0026lt;0.001). Additionally, the first and second generation of \u003cem\u003eA. arabicum\u003c/em\u003e host switch had significantly higher longevity than the \u003cem\u003eB. germari\u003c/em\u003e control (P\u0026lt;0.001). In general, it was found that switching the host from \u003cem\u003eB. germari\u003c/em\u003e to \u003cem\u003eA. arabicum\u003c/em\u003e increases the longevity of females, while switching the host from \u003cem\u003eA. arabicum\u003c/em\u003e to \u003cem\u003eB. germari\u003c/em\u003e significantly reduces longevity (\u003cstrong\u003eTable 1)\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e1-4- Total eggs parasitized and eggs parasitized on the first day post-emergence\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe total number of eggs parasitized during the lifespan of a female wasp, particularly the number of eggs parasitized on the first day post-emergence, are two crucial factors when studying egg parasitoids for biological control (Marchiori, 2022) and when selecting hosts for mass-rearing and release (Conti et al. 2021; Dyck et al. 2021). ANOVA analyses found significant differences in total parasitism (F\u003csub\u003e2,27\u003c/sub\u003e=24.569, P\u0026lt;0.001) and first day parasitism (F\u003csub\u003e2,27\u003c/sub\u003e=15.922, P\u0026lt;0.001) between treatments (\u003cstrong\u003eTable 1\u003c/strong\u003e). The total number of eggs parasitized during the wasps\u0026apos; lifetime was higher in the \u003cem\u003eB. germari\u003c/em\u003e control compared to the \u003cem\u003eA. arabicum\u003c/em\u003e control (P\u0026lt;0.001), and was also higher in the \u003cem\u003eA. arabicum\u003c/em\u003e control compared to the first generation of its host switch (P=0.017). Total parasitism was also higher in the \u003cem\u003eB. germari\u003c/em\u003e control compared to the first (P\u0026lt;0.001) and second generations host-switched to \u003cem\u003eB. germari\u003c/em\u003e (P\u0026lt;0.001). Moreover, the number of eggs parasitized on the first day post-emergence was higher in the \u003cem\u003eA. arabicum\u003c/em\u003e control compared to the \u003cem\u003eB. germari\u003c/em\u003e control (P\u0026lt;0.001). Also, the number of eggs parasitized on the first day post-emergence was higher in the first generation host-switched to \u003cem\u003eB. germari\u003c/em\u003e compared to the \u003cem\u003eB. germari\u003c/em\u003e control (P=0.008). This would indicate that rearing parasitoids on \u003cem\u003eA. arabicum\u003c/em\u003e would result in the same or increased parasitism by \u003cem\u003eP. saccharicola\u003c/em\u003e, while rearing on \u003cem\u003eB. germari\u003c/em\u003e would result in reduced parasitism, should host switching occur after release. Daily egg parasitism by \u003cem\u003eP. saccharicola\u003c/em\u003e is shown in \u003cstrong\u003eFig. 1\u003c/strong\u003e and \u003cstrong\u003eFig. 2\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eBiological characteristics of \u003cem\u003eP. saccharicola\u003c/em\u003e reared on \u003cem\u003eA. arabicum\u003c/em\u003e and \u003cem\u003eB. germari\u003c/em\u003e\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e2-1- Development time\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eANOVA analyses showed significant differences in male (F\u003csub\u003e2,27\u003c/sub\u003e=132.771, P\u0026lt;0.001) and female (F\u003csub\u003e2,27\u003c/sub\u003e=97.878, P\u0026lt;0.001) development time between treatments. Post-hoc tests revealed that \u003cem\u003eP. saccharicola\u003c/em\u003e males and females in the \u003cem\u003eB. germari\u003c/em\u003e control had longer development periods than in the first (male: P\u0026lt;0.001; female: P\u0026lt;0.001) and second generations host-switched to \u003cem\u003eB. germari\u003c/em\u003e (male: P=0.048; female: P=0.028).\u0026nbsp;In contrast, the \u003cem\u003eA. arabicum\u003c/em\u003e control had shorter development times compared to the first generation host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e (male: P\u0026lt;0.001; female: P\u0026lt;0.001). Furthermore, the \u003cem\u003eA. arabicum\u003c/em\u003e control had shorter development times than the \u003cem\u003eB. germari\u003c/em\u003e control (male: P\u0026lt;0.001; female: P\u0026lt;0.001). Notably, the \u003cem\u003eB. germari\u003c/em\u003e control had the longest development time for both males (15.2 \u0026plusmn; 0.1 days) and females (16.5 \u0026plusmn; 0.2 days), while the \u003cem\u003eA. arabicum\u003c/em\u003e control had the shortest female development period (12.7 \u0026plusmn; 0.1 days) and the second generation host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e had the shortest male development period (11.6 \u0026plusmn; 0.2 days, \u003cstrong\u003eTable 2\u003c/strong\u003e). These results indicated that \u003cem\u003eA. arabicum\u003c/em\u003e eggs may be higher quality than \u003cem\u003eB. germari\u003c/em\u003e for \u003cem\u003eP. saccharicola\u003c/em\u003e rearing, resulting in faster larval growth and development.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e2-2- Sex ratio\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;There was a significant difference in the \u003cem\u003eP. saccharicola\u003c/em\u003e sex ratio between treatments (F\u003csub\u003e2,27\u003c/sub\u003e=8.565, P\u0026lt;0.001). The \u003cem\u003eA. arabicum\u003c/em\u003e control produced a higher ratio of female wasps than the \u003cem\u003eB. germari\u003c/em\u003e control (P\u0026lt;0.001). However, no differences were observed between the \u003cem\u003eB. germari\u003c/em\u003e control and the first (P=0.245) and second generations host-switched to \u003cem\u003eB. germari\u003c/em\u003e (P=0.270). Similarly, no differences were found between the \u003cem\u003eA. arabicum\u003c/em\u003e control and the first (P=0.536) and second generations host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e (P=0.219). The \u003cem\u003eA. arabicum\u003c/em\u003e control had the highest sex ratio, while the \u003cem\u003eB. germari\u003c/em\u003e control had the lowest sex ratio (\u003cstrong\u003eTable 2\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e2-3- Survival rate\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eSurvival data revealed that the \u003cem\u003eB. germari\u003c/em\u003e control (0.857 \u0026plusmn; 0.016) had a significantly lower survival rate compared to the \u003cem\u003eA. arabicum\u003c/em\u003e control (0.952 \u0026plusmn; 0.004, F\u003csub\u003e2,27\u003c/sub\u003e=14.373, P\u0026lt;0.001). No significant differences were found between any other treatments. In general, it seems host switching did not influence survival rate (\u003cstrong\u003eTable 2\u003c/strong\u003e).\u003c/p\u003e\n\u003cp\u003e\u003cu\u003eLife table parameters of \u003cem\u003eP. saccharicola\u003c/em\u003e reared on \u003cem\u003eB. germari\u003c/em\u003e and \u003cem\u003eA. arabicum\u003c/em\u003e\u003c/u\u003e\u003c/p\u003e\n\u003cp\u003eStatistical results for life table parameters between treatments are presented in \u003cstrong\u003eTable 3\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3-1- Net reproductive rate\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eAn ANOVA showed significant differences in net reproductive rate (F\u003csub\u003e2,27\u003c/sub\u003e=1139.152, P\u0026lt;0.001). The \u003cem\u003eB. germari\u003c/em\u003e control had a higher net reproductive rate than the \u003cem\u003eA. arabicum\u003c/em\u003e control (P\u0026lt;0.001). Additionally, the \u003cem\u003eA. arabicum\u003c/em\u003e control had a significantly higher reproductive rate compared to the first (P\u0026lt;0.001) and second generations of \u003cem\u003eA. arabicum\u003c/em\u003e host-switch (P\u0026lt;0.001). Similarly, the reproductive rate in the \u003cem\u003eB. germari\u003c/em\u003e control was higher than in the first (P\u0026lt;0.001) and second generations of wasps host-switched \u003cem\u003eB. germari\u003c/em\u003e (P\u0026lt;0.001). The \u003cem\u003eB. germari\u003c/em\u003e control has the highest net reproductive rate (117.24 \u0026plusmn; 0.4), indicating that using \u003cem\u003eB. germari\u003c/em\u003e eggs as hosts would produce more females. Notably, the second generation of \u003cem\u003eB. germari\u003c/em\u003e host-switch has the lowest net reproductive rate, significantly lower than all other treatments (81.1 \u0026plusmn; 0.2).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3-2- Intrinsic rate of increase\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eANOVA results showed differences in intrinsic rate of increase between treatments (F\u003csub\u003e2,27\u003c/sub\u003e= 223.281, P = 0.000). While the net reproduction rate was highest in the \u003cem\u003eB. germari\u003c/em\u003e control, it was found that the intrinsic rate of increase in the \u003cem\u003eA. arabicum\u003c/em\u003e control (0.323 \u0026plusmn; 0.001) was higher compared to the \u003cem\u003eB. germari\u003c/em\u003e control (P = 0.000). The lowest intrinsic rates of increase were recorded for \u0026nbsp;\u003cem\u003eB. germari\u003c/em\u003e control (0.250 \u0026plusmn; 0.001) and the second generation of wasps host-switched to \u003cem\u003eB. germari\u003c/em\u003e control (0.251\u0026plusmn; 0.001), with a significant difference compared to the other treatments (\u003cstrong\u003eTable 3\u003c/strong\u003e). Additionally, significant differences were observed between the \u003cem\u003eA. arabicum\u003c/em\u003e control and the first (P\u0026lt;0.001) and second generations of wasps host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e (P\u0026lt;0.001). However, for \u003cem\u003eB. germari\u003c/em\u003e treatments, a significant difference was observed only between the first generation host-switched to \u003cem\u003eB. germari\u003c/em\u003e and the \u003cem\u003eB. germari\u003c/em\u003e control (P\u0026lt;0.001). Results illustrated when wasps host-switched from \u003cem\u003eB. germari\u003c/em\u003e to \u003cem\u003eA. arabicum\u003c/em\u003e the intrinsic rate of increase declined significantly in comparison to the \u003cem\u003eA. arabicum\u003c/em\u003e control, however the reverse occurred when host switching from \u003cem\u003eA. arabicum\u003c/em\u003e to \u003cem\u003eB. germari\u003c/em\u003e compared to the \u003cem\u003eB. germari\u003c/em\u003e control, at least in the first generation.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3-3- Finite rate of increase\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eANOVA results revealed differences in the finite rate of increase between treatments (F\u003csub\u003e2,27\u003c/sub\u003e= 232.317, P\u0026lt;0.001). As predicted based on the intrinsic rate of increase, the \u003cem\u003eA. arabicum\u003c/em\u003e control had a greater finite rate of increase compared to the \u003cem\u003eB. germari\u003c/em\u003e control (P\u0026lt;0.001). Furthermore, the finite rate of increase for the \u003cem\u003eA. arabicum\u003c/em\u003e control was higher compared to the first (P\u0026lt;0.001) and second generations host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e (P\u0026lt;0.001). This shows that the wasp population developed more slowly when switched from \u003cem\u003eB. germari\u003c/em\u003e to \u003cem\u003eA. arabicum\u003c/em\u003e in comparison to the control treatments. The finite rate of increase in the \u003cem\u003eB. germari\u003c/em\u003e control was less than first generation of wasps switched to \u003cem\u003eB. germari\u003c/em\u003e (P\u0026lt;0.001). However, no difference was observed between the \u003cem\u003eB. germari\u003c/em\u003e control and the second generation host-switch (P=1.000). Notably, the \u003cem\u003eA. arabicum\u003c/em\u003e control had the highest finite population increase rate (1.382 \u0026plusmn; 0.001), while the second generation wasps host-switched to \u003cem\u003eB. germari\u003c/em\u003e (1.285 \u0026plusmn; 0.001) and the \u003cem\u003eB. germari\u003c/em\u003e control treatment (1.285 \u0026plusmn; 0.002), had the lowest finite population increase rate.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3-4- Mean generation time\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eANOVA analysis showed significant differences in generation time between treatments (F\u003csub\u003e2,27\u003c/sub\u003e=85908.824, P\u0026lt;0.001), with following post-hoc tests finding all treatments different from each other P\u0026lt;0.001). Interestingly, switching the host from \u003cem\u003eA. arabicum\u003c/em\u003e to \u003cem\u003eB. germari\u003c/em\u003e significantly decreased the mean generation time compared to the \u003cem\u003eB. germari\u003c/em\u003e control (P\u0026lt;0.001). The \u003cem\u003eA. arabicum\u003c/em\u003e control treatment has the shortest mean generation time (14.14 \u0026plusmn; 0.003 days), followed by the second generation host-switched to \u003cem\u003eA. arabicum\u003c/em\u003e (14.96 \u0026plusmn; 0.006). In contrast, the \u003cem\u003eB. germari\u003c/em\u003e control treatment had the longest average mean generation time (18.685 \u0026plusmn; 0.006), followed by the second generation host-switched to \u003cem\u003eB. germari\u003c/em\u003e (17.373\u0026plusmn; 0.004).\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e3-5- Population doubling time\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eANOVA analysis revealed significant differences in population doubling time (DT) F\u003csub\u003e2,27\u003c/sub\u003e=166.440, P\u0026lt;0.001). The \u003cem\u003eA. arabicum\u003c/em\u003e control had a much lower than the \u003cem\u003eB. germari\u003c/em\u003e control (P\u0026lt;0.001). The \u003cem\u003eA. arabicum\u003c/em\u003e control had the shortest DT (2.149 \u0026plusmn; 0.006), while the \u0026nbsp;\u003cem\u003eB. germari\u003c/em\u003e control has the longest DT (2.768 \u0026plusmn; 0.10, P\u0026lt;0.001). Moreover, these results showed that when wasps were host-switched from \u003cem\u003eA. arabicum\u003c/em\u003e to \u003cem\u003eB. germari\u003c/em\u003e the DT increased dramatically. Notably, there was no statistically significant difference between the \u003cem\u003eB. germari\u003c/em\u003e control treatment and the second generation host-switched to \u003cem\u003eB. germari\u003c/em\u003e (P=1.000).\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eOne of the most important factors affecting the performance of a parasitoid biological control agent is its host (Huffaker and Messenger \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e1976\u003c/span\u003e; Henry et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Looking at the impact of different host species on parasitoid fitness is imperative for determining the suitability of a host for rearing. Of the life table parameters examined in this study, intrinsic rate of increase, or net growth of a population, is an especially vital index for mass-rearing. This factor can be used to compare the effect of rearing conditions on parasitoid population growth, thus allowing for the determination of the most efficient rearing protocols as well as estimating success of establishment upon release (Bigler \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1989\u003c/span\u003e; Chi \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Strong and Pemberton \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2000\u003c/span\u003e). Our study revealed that, among the experimental treatments, the \u003cem\u003eA. arabicum\u003c/em\u003e control group exhibited the highest rate of population increase in \u003cem\u003eP. saccharicola\u003c/em\u003e.In general, our findings indicated that rearing \u003cem\u003eP. saccharicola\u003c/em\u003e on \u003cem\u003eA. arabicum\u003c/em\u003e is more efficient than rearing on \u003cem\u003eB. germari\u003c/em\u003e, as \u003cem\u003eA. arabicum\u003c/em\u003e eggs resulted in more progeny, a faster development time, and a higher female-to-male sex ratio (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThis study illustrates that \u003cem\u003eP. saccharicola\u003c/em\u003e development and reproduction is affected by host species. Future research may provide information on the mechanisms behind the observed differences in parasitoid fitness, allowing for the development of more efficient rearing protocols. Differences in host suitability have been attributed to phylogenetic relationships between the host species and similarities/ differences in kairomones in other parasitoid-host systems (Drost and Carde 1992). Additionally, research has linked the reproductive rate, finite rate of increase and survival rate of progeny to the percentage of compounds and proportion of nutrients in the host's body (Bourchier et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Rakhshani et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Jones et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2015\u003c/span\u003e).\u003c/p\u003e \u003cp\u003ePrevious studies found that \u003cem\u003eA. arabicum\u003c/em\u003e and \u003cem\u003eB. germari\u003c/em\u003e have high density populations in pistachio orchards during the growing season (Hashemi Rad \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Mehrnejad et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Since the \u003cem\u003eP. saccharicola\u003c/em\u003e laboratory populations used in this study were established with individuals collected from pistachio orchards it can be surmised that this wasp co-evolved with both species. However, it has also been reported that \u003cem\u003eB. germari\u003c/em\u003e is migratory and spends winter in the hills and mountains, while \u003cem\u003eA. arabicum\u003c/em\u003e generally overwinters in the same area of pistachio orchards (Hashemi Rad \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Mehrnejad et al. \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). The results suggest that the \u003cem\u003eP. saccharicola\u003c/em\u003e wasp population had greater compatibility with \u003cem\u003eA. arabicum\u003c/em\u003e. Should \u003cem\u003eP. saccharicola\u003c/em\u003e overwinter in the orchards with \u003cem\u003eA. arabicum\u003c/em\u003e, this may explain the increased compatibility between these two species. During our collections we did not detect \u003cem\u003eP. saccharicola\u003c/em\u003e outside of pistachio orchards, however further investigations into their overwintering behavior may shed light on their host preferences.\u003c/p\u003e \u003cp\u003eBased on the finite rates of increase found in this study,, where λ was found to be greater than 1 in all treatments, rearing \u003cem\u003eP. saccharicola\u003c/em\u003e on either host would lead to an increase in the total wasp population. This holds true for wasps that stay on the same host they are reared on, as well as wasps that host-switch in the lab or potentially after release into the environment. It was observed that switching the host from \u003cem\u003eA. arabicum\u003c/em\u003e to \u003cem\u003eB. germari\u003c/em\u003e results in a significant decrease in doubling time in the first generation of host-switch. This suggests that using \u003cem\u003eA. arabicum\u003c/em\u003e as a host enables \u003cem\u003eP. saccharicola\u003c/em\u003e populations to grow quickly, resulting in efficient lab-rearing and ultimately achieving pest control in a shorter period of time. Based on these results and intrinsic rates of increase, we conclude that \u003cem\u003eA. arabicum\u003c/em\u003e is the most suitable host for mass-rearing \u003cem\u003eP. saccharicola\u003c/em\u003e.\u003c/p\u003e \u003cp\u003eDue to declines in parasitoid fitness resulting from lab rearing on a single host, it is important to determine the impact of switching to another suitable host on parasitoid performance. When a biological control agent is reared on one host and then switched to another, a decrease in life table parameters, especially the finite rate of increase, may indicate that mass-rearing on a host could negatively impact the parasitoid's fitness and adaptability once released into the environment. However, if these parameters increase or remain unchanged after host switching it may be hoped that lab-reared parasitoids will be reproductively successful, resulting in effective biological control. In another parasitoid-host system, a host switching test was conducted on the parasitoid \u003cem\u003eSpalangia endius\u003c/em\u003e Walker and two economically significant pest flies, \u003cem\u003eBactrocera dorsalis\u003c/em\u003e Hendel and \u003cem\u003eMusca domestica\u003c/em\u003e L. It was observed that the performance of \u003cem\u003eS. endius\u003c/em\u003e gradually declined after being reared on \u003cem\u003eM. domestica\u003c/em\u003e for 50 consecutive generations (Zheng et al. \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, after a single generation of host-switch to \u003cem\u003eB. dorsalis\u003c/em\u003e, the wasp's performance returned to its original level. In the previously mentioned \u003cem\u003eT. drosophilae\u003c/em\u003e system, parasitism performance could be enhanced by rearing on \u003cem\u003eD. suzukii\u003c/em\u003e before release, after continuous rearing on the host \u003cem\u003eD. melanogaster\u003c/em\u003e (Boycheva Woltering et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Therefore, it is suggested that the use of alternative hosts and host switching is essential for the successful and long-term rearing of the parasitoids.\u003c/p\u003e \u003cp\u003eBy investigating the impacts of host-switching over two generations, we could observe how long it would take for parasitoid performance to recover after a host-switch. In the current study, \u003cem\u003eP. saccharicola\u003c/em\u003e was found to oviposit on eggs of both hosts, \u003cem\u003eA. arabicum\u003c/em\u003e and \u003cem\u003eB. germari\u003c/em\u003e. Generally, there is little difference in the wasp\u0026rsquo;s ability to effectively parasitize these two hosts, as the wasp's performance in the second generation after a host-switch resembles that of the control generation. This suggests that if a decline in performance occurs after several generations reared on the \u003cem\u003eA. arabicum\u003c/em\u003e, it is likely that this decline can be mitigated by a single host-switch, restoring the wasp's performance to its maximum after two generations of rearing on a new host such as \u003cem\u003eB. germari\u003c/em\u003e.\u003c/p\u003e \u003cp\u003eTo implement augmentative biological control successfully, rearing protocols must be streamlined to produce biological control agents as quickly and cost-effectively as possible. As our study has shown, finding the most efficient host for rearing parasitoids with multiple hosts and determining the effects of host switching on reproduction is necessary for a practical rearing operation and successful releases. To build off these laboratory findings, complementary field studies are critical to predict if \u003cem\u003eP. saccharicola\u003c/em\u003e will significantly impact pentatomid populations and if lab-reared individuals will be successful biological control agents. Potential studies may include long-term surveys to determine the current pest densities of \u003cem\u003eA. arabicum\u003c/em\u003e and \u003cem\u003eB. germari\u003c/em\u003e as well as in-field parasitism rates for \u003cem\u003eP. saccharicola\u003c/em\u003e. Other factors that should be further explored include \u003cem\u003eP. saccharicola\u003c/em\u003e host-range studies and the presence of other hosts in pistachio orchards. Further work may be done to evaluate the success of these lab reared individuals in finding hosts and reproducing in the field. It is also important to note that while the results of this study have implications for how \u003cem\u003eP. saccharicola\u003c/em\u003e will fare after release into the environment, exposure to other potential hosts and variable field conditions may impact population growth. This information will ultimately be essential to the implementation of a rearing program for \u003cem\u003eP. saccharicola\u003c/em\u003e and will allow for more sustainable pest control in pistachio orchards.\u003c/p\u003e \u003cp\u003eWe conclude that mass production of \u003cem\u003eP. saccharicola\u003c/em\u003e for augmentation in pistachio orchards can be safely carried out using eggs of \u003cem\u003eA. arabicum\u003c/em\u003e, which are more easily and cost-effectively produced than eggs of \u003cem\u003eB. germari\u003c/em\u003e, without any significant negative consequences for their fitness or performance on the more suitable host. However, release rates should take into account the fact that most stink bug egg masses will not be fully parasitized by a single wasp encounter due to the observed egg load constraints.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eThe authors have no competing interests to declare that are relevant to the content of this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data supporting the findings of this study are available within the paper.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAbbas Esmaeili Sardary: Conceptualization, data collection, writing original draft. Fatemeh Ranjbar: Conceptualization, experimental design, data analysis. Sabrina L. Celis: Results interpretation, writing and editing. M. Amin Jalali: Supervision, conceptualization, experimental design, methodology. Mahdi Ziaaddini: Visualization, methodology.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors are grateful to Vali-e-Asr University of Rafsanjan, Iran, for financial support to AES. (MS student no. 99124006). This work was funded, in part, by the Biotechnology Development Council of the Islamic Republic of Iran, Grant No: biodc-2002275-2002140.1.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAbram PK, Mills NJ, Beers EH (2020) Review: classical biological control of invasive stink bugs with egg parasitoids \u0026ndash; what does success look like? Pest Manag Sci 76: 1980-1992 https://doi.org/10.1002/ps.5813\u003c/li\u003e\n\u003cli\u003eBerm\u0026uacute;dez NC, de la Pava N, C\u0026aacute;ceres JSD, da Silva-Torres CSA, Torres JB (2024) Long-term suitability of an alternative host for rearing the sugarcane stalk borer parasitoid \u003cem\u003eTetrastichus howardi\u003c/em\u003e. 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International Food and Agribusiness Management Review 15: 139-154 http://dx.doi.org/10.22004/ag.econ.133490\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1.\u0026nbsp;\u003c/strong\u003eMean (\u0026plusmn; SE) number of females observed (n), oviposition period (\u003cem\u003eOP\u003c/em\u003e), post oviposition period (\u003cem\u003ePOP\u003c/em\u003e), female longevity (\u003cem\u003eFL\u003c/em\u003e), total number of eggs parasitized (\u003cem\u003eTP\u003c/em\u003e), and number of eggs parasitized in the first day (\u003cem\u003eN\u003csup\u003e1st\u003c/sup\u003e\u003c/em\u003e) for \u003cem\u003epsix saccharicola\u003c/em\u003e reared on \u003cem\u003eAcrosternum arabicum\u003c/em\u003e and \u003cem\u003eBrachynema germari\u003c/em\u003e in the no-switch controls, and the first and second host-switched generations. The averages displayed with the same letters in each column are not significantly different from each other (Tukey HSD test, \u0026alpha; = 0.05).\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"789\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eHost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eTreatment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6.0836%;\"\u003e\n \u003cp\u003en\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003eOP\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003ePOP\u003c/p\u003e\n \u003cp\u003e(days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 118px;\"\u003e\n \u003cp\u003eFL\u003c/p\u003e\n \u003cp\u003e(days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eTP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14.8289%;\"\u003e\n \u003cp\u003eN\u003csup\u003e1st\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6.0836%;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e8.727b\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.384)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 106px;\"\u003e\n \u003cp\u003e4.091cd\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.436)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e12.818c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.263)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e112.910b\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;1.246)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14.8289%;\"\u003e\n \u003cp\u003e83.0910a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;1.528)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e\u003cem\u003eAcrosternum arabicum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e1st generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6.0836%;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e11.556a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.835)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 106px;\"\u003e\n \u003cp\u003e5.000c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.898)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e16.556a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.176)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e95.222c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;7.794)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14.8289%;\"\u003e\n \u003cp\u003e53.889d\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;5.059)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e2nd generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6.0836%;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e4.600c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.718)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 106px;\"\u003e\n \u003cp\u003e9.700a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.716)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e14.300b\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.367)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e101.700bc\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;2.708)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14.8289%;\"\u003e\n \u003cp\u003e70.900bc\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;2.297)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6.0836%;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e11.300a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.213)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 106px;\"\u003e\n \u003cp\u003e2.600de\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.305)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e13.900bc\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.233)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e144.300a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;3.916)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14.8289%;\"\u003e\n \u003cp\u003e62.900cd\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;3.035)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e\u003cem\u003eBrachynema germari\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e1st generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6.0836%;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e6.300c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.213)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 106px;\"\u003e\n \u003cp\u003e1.500e\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.167)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e7.800e\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.133)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e112.300b\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;2.499)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14.8289%;\"\u003e\n \u003cp\u003e76.500ab\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;1.232)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e2nd generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 6.0836%;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp\u003e1.900e\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.277)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 106px;\"\u003e\n \u003cp\u003e7.500b\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.224)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e9.400d\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.340)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 106px;\"\u003e\n \u003cp\u003e94.900c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;1.670)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 14.8289%;\"\u003e\n \u003cp\u003e62.500cd\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;1.759)\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\u003e\u003cstrong\u003eTable 2.\u0026nbsp;\u003c/strong\u003eMean (\u0026plusmn; SE) development times of females (female) and males (male), progeny sex ratio (sex ratio) and progeny survival (survival) for \u003cem\u003epsix saccharicola\u003c/em\u003e reared on \u003cem\u003eAcrosternum arabicum\u003c/em\u003e and \u003cem\u003eBrachynema germari\u003c/em\u003e in the no-switch controls, and the first and second host-switched generations. The averages displayed with the same letters in each column are not significantly different from each other (Tukey HSD test, \u0026alpha; = 0.05). * Is the number of females\u0026apos; offsprings which observed.\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"759\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003eHost\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003eTreatment\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eDevelopment time\u003c/p\u003e\n \u003cp\u003e(day)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003eSex ratio\u003c/p\u003e\n \u003cp\u003e(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003eSurvival\u003c/p\u003e\n \u003cp\u003e(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 147px;\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 129px;\"\u003e\n \u003cp\u003e12.734\u0026plusmn;0.118d\u003c/p\u003e\n \u003cp\u003e(15)*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 147px;\"\u003e\n \u003cp\u003e11.400\u0026plusmn;0.131e\u003c/p\u003e\n \u003cp\u003e(15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.929\u0026plusmn;0.004a\u003c/p\u003e\n \u003cp\u003e(11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.952\u0026plusmn;0.004a\u003c/p\u003e\n \u003cp\u003e(11)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u003cem\u003eAcrosternum\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003earabicum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003e1st generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 129px;\"\u003e\n \u003cp\u003e14.400\u0026plusmn;0.163c\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 147px;\"\u003e\n \u003cp\u003e13.000\u0026plusmn;0.000d\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.912\u0026plusmn;0.012ab\u003c/p\u003e\n \u003cp\u003e(9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.882\u0026plusmn;0.012cb\u003c/p\u003e\n \u003cp\u003e(9)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003e2nd generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 129px;\"\u003e\n \u003cp\u003e13.300\u0026plusmn;0.153d\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 147px;\"\u003e\n \u003cp\u003e11.600\u0026plusmn;0.163e\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.909\u0026plusmn;0.006ab\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.913\u0026plusmn;0.007b\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 129px;\"\u003e\n \u003cp\u003e16.500\u0026plusmn;0.167a\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 147px;\"\u003e\n \u003cp\u003e15.200\u0026plusmn;0.134a\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.871\u0026plusmn;0.010c\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.857\u0026plusmn;0.016c\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u003cem\u003eBrachynema\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e\u003cem\u003egermari\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003e1st generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 129px;\"\u003e\n \u003cp\u003e14.900\u0026plusmn;0.180c\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 147px;\"\u003e\n \u003cp\u003e13.700\u0026plusmn;0.153c\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.895\u0026plusmn;0.005bc\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.913\u0026plusmn;0.004b\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 113px;\"\u003e\n \u003cp\u003e2nd generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 129px;\"\u003e\n \u003cp\u003e15.800\u0026plusmn;0.134b\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"bottom\" style=\"width: 147px;\"\u003e\n \u003cp\u003e14.600\u0026plusmn;0.163b\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.894\u0026plusmn;0.006bc\u003c/p\u003e\n \u003cp\u003e(10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e0.917\u0026plusmn;0.006b\u003c/p\u003e\n \u003cp\u003e(10)\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\u003e\u003cstrong\u003eTable 3.\u0026nbsp;\u003c/strong\u003eMean (\u0026plusmn; SE) number of females observed (n), net reproductive rate (\u003cem\u003eR\u003csub\u003eo\u003c/sub\u003e\u003c/em\u003e), intrinsic rate of increase (\u003cem\u003er\u003csub\u003em\u003c/sub\u003e\u003c/em\u003e), finite rate of increase (\u003cem\u003e\u0026lambda;\u003c/em\u003e), mean generation time (\u003cem\u003eT\u003c/em\u003e), and doubling time (\u003cem\u003eDT\u003c/em\u003e) for \u003cem\u003epsix saccharicola\u003c/em\u003e reared on \u003cem\u003eAcrosternum arabicum\u003c/em\u003e and \u003cem\u003eBrachynema germari\u003c/em\u003e in the no-switch controls, and the first and second host-switched generations. The averages displayed with the same letters in each column are not significantly different from each other (Tukey HSD test, \u0026alpha; = 0.05).\u003c/p\u003e\n \u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"709\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 71px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 24px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"5\" style=\"width: 530px;\"\u003e\n \u003cp\u003eLife table parameters\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 84px;\"\u003e\n \u003cp\u003eHost\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 71px;\"\u003e\n \u003cp\u003eTreatment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 24px;\"\u003e\n \u003cp\u003en\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 112px;\"\u003e\n \u003cp\u003e\u003cem\u003eR\u003csub\u003eo\u003c/sub\u003e\u003c/em\u003e (females/female)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u003cem\u003er\u003csub\u003em\u003c/sub\u003e\u003c/em\u003e (females/female/day)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e\u003cem\u003e\u0026lambda;\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(females/female/day)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003e\u003cem\u003eT\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003e\u003cem\u003eDT\u003c/em\u003e\u003c/p\u003e\n \u003cp\u003e(days)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 71px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 24px;\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 112px;\"\u003e\n \u003cp\u003e95.643b\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.106)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e0.323a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e1.381a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003e14.140f\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.003)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003e2.149e\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.006)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cem\u003eAcrosternum arabicum\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 71px;\"\u003e\n \u003cp\u003e1st generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 24px;\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 112px;\"\u003e\n \u003cp\u003e76.123f\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.779)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e0.262d\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.005)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e1.299d\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.006)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003e16.578c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.010)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003e2.657b\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.045)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 71px;\"\u003e\n \u003cp\u003e2\u003csup\u003end\u003c/sup\u003e generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 24px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 112px;\"\u003e\n \u003cp\u003e84.338d\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.250)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e0.300b\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.0001)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e1.345b\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.002)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003e14.955e\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.006)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003e2.338d\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.011)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 71px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 24px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 112px;\"\u003e\n \u003cp\u003e107.733a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.325)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e0.250e\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e1.285e\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003e18.685a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.006)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003e2.768a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.013)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 84px;\"\u003e\n \u003cp\u003e\u003cem\u003eBrachynema germari\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 71px;\"\u003e\n \u003cp\u003e1st generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 24px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 112px;\"\u003e\n \u003cp\u003e91.744c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.227)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e0.277c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e1.319c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003e16.335d\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.003)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003e2.506c\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.010)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 84px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 71px;\"\u003e\n \u003cp\u003e2\u003csup\u003end\u003c/sup\u003e generation switch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 24px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 112px;\"\u003e\n \u003cp\u003e77.776e\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.152)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e0.251e\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 132px;\"\u003e\n \u003cp\u003e1.285e\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.001)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 77px;\"\u003e\n \u003cp\u003e17.373b\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.004)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp\u003e2.766a\u003c/p\u003e\n \u003cp\u003e(\u0026plusmn;0.010)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"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":"biological control, life table, Pentatomidae, Hymenoptera, Scelionidae","lastPublishedDoi":"10.21203/rs.3.rs-5185542/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5185542/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eTo successfully implement augmentative biological control, it is imperative to identify the most efficient host for parasitoid rearing and the impact of host switching on reproduction when multiple hosts are available. This study examined the effect of host switching on parasitoid fitness and reproduction using the wasp \u003cem\u003ePsix saccharicola\u003c/em\u003e Mani (Hymenoptera: Scelionidae), a dominant stink bug egg parasitoid in Iranian pistachio orchards, and two common hosts— \u003cem\u003eAcrosternum arabicum\u003c/em\u003e Wagner (Hemiptera: Pentatomidae) and \u003cem\u003eBrachynema germari\u003c/em\u003eKolenati (Hemiptera: Pentatomidae). The results indicated that rearing wasps on \u003cem\u003eA. arabicum\u003c/em\u003e was more efficient, resulting in a shorter population doubling time, a shorter mean generation time, and higher finite and intrinsic rates of increase compared to rearing on \u003cem\u003eB. germari\u003c/em\u003e. While switching the host from \u003cem\u003eA. arabicum\u003c/em\u003e to \u003cem\u003eB. germari\u003c/em\u003e led to increased population growth parameters for \u003cem\u003eP. saccharicola\u003c/em\u003e in the first generation of host switching, switching the host from \u003cem\u003eB. germari\u003c/em\u003e to \u003cem\u003eA. arabicum\u003c/em\u003e decreased parasitoid fitness and reproduction. However, the effect of host switching largely disappeared in the second generation after host-switch, suggesting that changes in parasitoid fitness due to host switching could be temporary and may revert in subsequent generations. Our study highlights the importance of evaluating the impact of host switching when implementing a rearing program for \u003cem\u003eP. saccharicola\u003c/em\u003e, ultimately leading to more sustainable pest control of stink bugs in pistachio orchards.\u003c/p\u003e","manuscriptTitle":"Fitness consequences of host switching by Psix saccharicola, a stink bug egg parasitoid in pistachio orchards","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-16 13:05:16","doi":"10.21203/rs.3.rs-5185542/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":"eae04f48-aa0c-46b7-895b-cc85f5f8f41d","owner":[],"postedDate":"December 16th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-02-18T10:38:12+00:00","versionOfRecord":[],"versionCreatedAt":"2024-12-16 13:05:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5185542","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5185542","identity":"rs-5185542","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}