Impact of Habitat Fragmentation on Reduviid (Hemiptera: Reduviidae) Diversity and Predation Dynamics in the Southern Western Ghats of Tamil Nadu, India

Impact of Habitat Fragmentation on Reduviid (Hemiptera: Reduviidae) Diversity and Predation Dynamics in the Southern Western Ghats of Tamil Nadu, India | 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 Impact of Habitat Fragmentation on Reduviid (Hemiptera: Reduviidae) Diversity and Predation Dynamics in the Southern Western Ghats of Tamil Nadu, India M Muthupandi, Manimaran Arokiasamy, Melvin A Daniel This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6350470/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 Climate change is expected to significantly impact biodiversity, including predator-prey interactions. This study investigated the distribution and diversity of reduviid predators (Reduviidae), potential biocontrol agents of agricultural and forest insect pests, across three distinct habitats in the Southern Western Ghats, Tamil Nadu, India, over 12 months. Understanding baseline diversity and distribution is crucial for predicting climate change impacts. A total of 641 individuals, representing 7 sub-families, 24 genera, and 31 species were recorded from the Killikulam semi-arid zone (SAZ), Aralvoimozhi scrub jungle (SJ), and Godayar tropical forest (TF). Species richness was highest in the SJ ( 22 ), followed by the SAZ ( 13 ) and TF ( 9 ). Seasonal variations in predator populations were observed, with peaks during winter in the SAZ, summer in the SJ, and also summer in the TF. The dominant reduviid species were Edocla slateri and Rhynocoris fuscipes (50%), followed by Acanthapis pedestris and Catamirus brevipennis (44.4%) and Irantha armipes (38.9%). These dominant species, potentially valuable for pest management, may exhibit varying responses to changing climatic conditions. The SJ exhibited a higher Shannon-Weiner index (2.552) than Simpson’s index (0.146), indicating greater diversity. While specific prey populations appear to influence the distribution of certain reduviid species, regardless of habitat, future research should investigate how climate change-induced shifts in temperature, rainfall patterns, and prey availability might alter these relationships. This baseline data is essential for developing climate-smart conservation strategies for reduviid predators and ensuring their continued effectiveness as biocontrol agents in the face of climate change. Reduviid predators Climate change diversity indices habitat Southern Western Ghats biological control agent Figures Figure 1 Figure 2 1. INTRODUCTION Studies on forest biodiversity are crucial in modern ecology, as forest ecosystems, both tropical and temperate, harbor a significant portion of global biodiversity. These populations are influenced by a complex interplay of biotic and abiotic factors, including the rapidly changing climate. While research on animal and plant communities in forests is increasing, the Western Ghats, a biodiversity hotspot, remain understudied in the context of global forest diversity, particularly concerning the impacts of climate change. This mountain range, running parallel to India's west coast, from the Tapti River to Kanyakumari, is a critical ecological zone. Existing research on reduviid predator diversity and distribution in Tamil Nadu, including studies by Ambrose (1980), Venison (1989), Sahayaraj (1991), Edwin (1997), Murugan (1988), Ravichandrean (1988), and Sivaramakrishnan (2009), provides a foundation. Further afield, studies like Haviland's (1931) and Revel et al.'s (2010) work in the Guianese rainforest offer comparative insights. Reduviids (Reduviidae), a species-rich and globally prevalent insect taxon, contribute significantly to forest biodiversity and play diverse roles in ecosystem dynamics and functioning (Goel, 1978; Murugan, 1988; Ravichandran, 1988; Kumaraswami and Ambrose, 1994; Edwin and Ambrose, 1996; Rajan and Ambrose, 1996; Edwin, 1997; Daniel et al., 1992). Their role as effective predators capable of top-down biocontrol (Ambrose, 1999; Sahayaraj, 2006) is particularly important in maintaining ecological balance. Previous work has documented the distribution of various insect groups, including Psocids, Isoptera, Blattaria, Dermaptera, Diptera, Hemiptera, and Orthoptera (Anu et al., 2009), and nine heteropteran families (excluding Reduviidae) (Aland et al., 2010) in the southern Western Ghats. While valuable, these studies, along with subsequent research on reduviids in different parts of the Western Ghats (Ambrose, 1980; Venison, 1989; Sahayaraj, 1991; Edwin, 1997; Sivaramakrishnan, 2009), lack a comprehensive, range-wide assessment, especially one considering the added pressure of climate change. Climate change, with its projected alterations in temperature, precipitation patterns, and extreme weather events, poses a significant threat to biodiversity, particularly in sensitive ecosystems like the Western Ghats. These changes can directly impact species distribution, abundance, and interactions, potentially disrupting ecosystem services like biocontrol. Understanding the current diversity and distribution of reduviids is crucial for establishing a baseline against which future climate-driven changes can be measured. How will shifts in temperature and rainfall affect the distribution of their prey? Will these changes favor certain reduviid species over others, leading to shifts in community composition? How will altered phenology (timing of life cycle events) affect predator-prey synchrony? These are critical questions that need to be addressed. Therefore, this study aims to address this gap by conducting a comprehensive survey of reduviid fauna in a semi-arid zone, scrub jungle, and forest region of the southern Western Ghats, Tamil Nadu, India. This research not only documents the diversity and distribution of reduviids but also establishes a crucial baseline for future studies examining the impacts of climate change. Furthermore, the study estimates key biodiversity indices, including evenness and richness, providing a more nuanced understanding of community structure. By focusing on these important predators, this research contributes to a broader understanding of the biogeography, organization, and dynamics of tropical communities in the Western Ghats and informs conservation strategies in the face of ongoing environmental change. 2. MATERIALS AND METHODS 2.1. Study Area and Sampling Design This study investigated reduviid predators and their prey insects across three distinct habitat types in the southern Western Ghats of Tamil Nadu, India, from 2023 to 2024. The selected habitats represent a gradient of environmental conditions: Semi-Arid Zone (SAZ): The Killikulam area (Latitude N 08°40’54.1” to 41’25.7”; Longitude E 077° 51’50.4” to 52’48.3”; altitude 35–55m) experiences hot, dry conditions. Scrub Jungle (SJ): The Aralvoimozhi area (Latitude N 08° 5’57.3” to 16’ 00.3” and Longitude E 077° 2’16.1” to 32’ 53.0”; altitude 106–158m) is characterized by a mix of thorny shrubs and dry deciduous vegetation. Tropical Forest (TF): The Godayar area (Latitude N 08° 31’ 09.2” to 32’ 31.6” and Longitude E 077°18’35.9” to 21’ 28.9”; altitude 116–1299m) represents a more forested and humid environment. To ensure representative sampling within each habitat type, two sampling sites were randomly selected, resulting in a total of six sites (two per habitat type). Each site consisted of a 5 x 5 m plot (following the methodology of John Christopher, 2009). The geographical coordinates (latitude and longitude) of each sampling site were recorded using a Garmin GPS map 76. This stratified sampling design allowed for comparisons of reduviid diversity and abundance across the different habitat types. These habitats were selected to represent a gradient of vegetation complexity and moisture availability within the southern Western Ghats. 2.2. Insect Collection and Identification Insect sampling was conducted monthly at each of the six study sites (two per habitat type) over the period 2023-2024. Sampling efforts targeted reduviid predators and their potential prey insects, encompassing a variety of microhabitats within each site. These microhabitats included: Arboreal: Insects were collected from tree trunks, branches, and foliage using sweep nets and visual searches. Litter: Leaf litter and other ground debris were carefully examined, and insects were collected using forceps and small camel hair brushes. Concealed Habitats: In the semi-arid zone and scrub jungle, stones were lifted (following Venison, 1989, and Sahayaraj, 1991) to collect reduviids and prey found underneath. In all habitats, bark crevices and other concealed spaces were also investigated. Sampling was primarily conducted during morning and evening hours to coincide with insect activity periods. Opportunistic collections were also made when encountering specimens outside of these regular sampling times. Collected insects were immediately anesthetized using ethyl acetate. In the laboratory, specimens were preserved using standard dry preservation techniques. Reduviids were identified to the lowest taxonomic level possible (species or genus, as appropriate). Other insects collected were also preserved and identified, particularly those considered potential prey items of the reduviids. Reduviids were identified using the taxonomic keys provided (Ambrose 1980). 2.3. Data analysis The Simpson’s index is calculated using the equation 1 (Magurran, 1988) D = _ {ni (ni -1)/N (N-1)} ------------------------------ (1) Where ni is the number of individuals in the ith species and N, the total number of individuals. Simpson’s index is usually expressed as 1- D or 1/ D, hence as D increases diversity of the community decreases. The Shannon index is calculated by using the formula 2: In this calculation the quantity Pi is the proportion of individuals found in the ith species. Where, ‘P’ is the proportion of the ‘i’th species in the community, s total number of species, in is the log with the base ‘e’ (natural logarithm) (Pielou, 1975). The overall similarity of different localities with species diversity (Cs) was calculated using the formula 3. A modified version of Jaccard formula as suggested by Sorennson (1948) was used. Similarity index Cs = 2j/a+b ---------------------------- (3) Where j is the number of species in common to the sites, a number of species in site a and b number of species in site b. Simson’ diversity index was calculated using the formula 4: Species evenness index was calculated by the formula 5: E = H”/In s ------------------------------------------ (5) Where ‘H’ is Shannon Index, In is the log with the base ‘e’ (natural logarithm),‘s’ total number of species. A one-way ANOVA with a significance level set at 5 % was used to compare means between topography. If the ANOVA test was significant a post hoc analysis was performed using the Tukey Honestly significant difference test (HSDT) (SPSS, 2001). The Chi-Square test of fit test is a non-parametric test which determines if there are significant differences between two or more sets of frequencies (Dytham, 2002). The underlying assumptions of this particular test is that individuals are independent, that individuals belong to only one category, and that the test is nonparametric or there is not an assumption about the shape of the underlying distribution. A Chi-Square test was used to determine the significance between the numbers of unique species of the Reduviidae of the 2009 – 2010 collection between ecotypes. 3. RESULTS 3.1. Reduviid Community Structure and Habitat Associations A total of 641 reduviid individuals, representing eight subfamilies, were collected across the three study habitats: Reduviinae (3 species), Harpactorinae (15), Peiratinae (6), Stenopodainae (2), Emesiinae (1), Ectrichodiinae (1), Holoptilinae (1), and Salyavatinae (1). The most prevalent species were Rhynocoris fuscipes and Edocla slateri (present in 50% of sampling sites), followed by Acanthapis pedestris and Catamirus brevipennis (44.4%), Irantha armipes (39%), Rhynocoris longifrons , Sirthena elongata , and Acanthaspis carinata (33.3%). Reduviid abundance differed significantly among the habitats (ANOVA: df = 1, 9; F = 249.388; p = 0.05). The scrub jungle (SJ) exhibited the highest abundance (70% of total individuals, n=492), comprising 22 species from 14 genera and four subfamilies (Harpactorinae, Stenopodainae, Peiratinae, Holoptilinae). The semi-arid zone (SAZ) accounted for 20% of the total (n=107), with 13 species from 10 genera, exclusively within the Harpactorinae subfamily (ANOVA: df = 3, 7; F = 0.431; p = 0.737). The tropical forest (TF) showed the lowest abundance (10%, n=42), also belonging only to the Harpactorinae subfamily (ANOVA: df = 3, 7; F = 0.963; p = 0.461). These findings contrast with previous research (Ambrose, 1999, 2006), which reported higher reduviid abundance in tropical forests. Chi-square tests indicated significant differences in species composition between the SJ and SAZ (χ² = 0.00189). Differences between TF and SJ (χ² = 0.017362) and between TF and SAZ (χ² = 0.049787) were also observed, though less pronounced. The observed patterns of reduviid diversity and abundance across habitats are likely to be influenced by climate change. Projected alterations in temperature and precipitation could differentially impact each habitat, potentially leading to shifts in reduviid community structure. Increased temperatures and reduced rainfall in the SAZ could further limit the diversity and abundance of reduviids, potentially favoring only the most tolerant species. Changes in rainfall patterns in the SJ and TF could alter vegetation structure and prey availability, indirectly affecting reduviid populations. Shifts in the phenology of reduviids and their prey could desynchronize their life cycles, impacting predation success. Changes in the distribution and abundance of prey insects, driven by climate change, could also have cascading effects on reduviid populations. The contrasting patterns observed in this study compared to earlier work (Ambrose, 1999, 2006) might already reflect some subtle shifts due to ongoing climate change. Long-term monitoring of reduviid communities is essential to disentangle the complex interactions between climate change, habitat characteristics, and species distributions, and to inform conservation management strategies for these important predators and biocontrol agents. 3.2. Habitat-Specific Reduviid Distribution and Abundance Tropical Forest (TF) - Godayar: The Godayar tropical forest, a high-elevation site in the Western Ghats, exhibited lower overall reduviid abundance (42 individuals, all within the Harpactorinae subfamily) but a more even species distribution (evenness, E = 0.969). Edocla plagiatus and Sycanus reclinatus were the dominant species, comprising 41% of the total insect collection in this habitat. Other Harpactorinae species were present but not notably dominant. Scrub Jungle (SJ) - Aralvoimozhi: The Aralvoimozhi scrub jungle, located near rice and floriculture agroecosystems, recorded peak reduviid populations in December 2023 (ANOVA: df = 2, 18; F = 4.274; p = 0.030) and May 2025 (ANOVA: df = 2, 18; F = 5.996; p = 0.010). Despite the proximity to agricultural areas where rice pests were observed, the dominant reduviid species in Aralvoimozhi was Acanthapis pedestris (18.5%), followed by Edocla slateri (14.8%) and Rhynocoris longifrons (13.6%) (Table 3) (Figure 2). Semi-Arid Zone (SAZ) - Killikulam: The Killikulam semi-arid zone, situated near the perennial Tamiraparani River and adjacent to agricultural lands cultivating crops like cotton, groundnut, castor, and cucumber, showed peak reduviid abundance in February (33 individuals) (ANOVA: df = 2, 18; F = 5.008; p = 0.010) and June (27 individuals) (ANOVA: df = 2, 18; F = 5.243; p = 0.011). Sastrapada elongata (38 individuals) and Acanthaspis carinata (21 individuals) were the dominant species in this habitat (Table 4) (Figure 2). Increased aridity in the semi-arid zone could further favor Sastrapada elongata and Acanthaspis carinata , potentially at the expense of other species. Shifts in rainfall patterns in the scrub jungle and tropical forest could alter vegetation structure and prey availability, leading to changes in the relative abundance of dominant reduviid species. Changes in the timing of pest outbreaks in adjacent agricultural areas, driven by climate change, could indirectly affect reduviid populations in the scrub jungle and semi-arid zone. The availability of water resources, particularly in the semi-arid zone, could also become a limiting factor for reduviids under future climate scenarios. Therefore, understanding the current habitat associations of reduviids is crucial for predicting their responses to climate change and for developing targeted conservation strategies. Long-term ecological monitoring is essential to track shifts in species distributions and abundances and to assess the effectiveness of conservation efforts. 3.3. Seasonal Abundance of Reduviids Four distinct seasons characterize the southern part of Tamil Nadu: winter (January and February), summer (March to May), southwest monsoon (June to September), and southeast monsoon (October to December). Reduviid seasonal abundance varied across the study sites. In the Killikulam semi-arid zone (SAZ), the highest reduviid population (37 individuals, representing five species) was observed during the southwest monsoon season (Figure 1). However, the relationship between season and abundance in the SAZ was not strong (r² = 0.252). The Aralvoimozhi scrub jungle (SJ) also showed peak reduviid abundance (160 individuals, 16 species) during the southwest monsoon season (Figure 1), with a strong positive correlation between season and abundance (r² = 0.829). In contrast, the Godayar tropical forest (TF) recorded the highest reduviid abundance (25 individuals, 6 species) during the summer season (Figure 1), exhibiting a very strong positive correlation (r² = 0.994). It's important to note that the overall abundance in the TF was considerably lower than in the other two habitats. 3.4. Diversity Indices and Prey Influence on Reduviid Populations 3.4.1. Diversity Indices The scrub jungle (SJ) exhibited the highest reduviid species richness and abundance (Table 5), with a significantly high population (p < 0.001, deviation = 30.77) and a relatively even distribution (E = 0.408). The semi-arid zone (SAZ) showed significantly lower reduviid abundance (p < 0.015, deviation = 10.71). Evenness values range from 0 to 1, with 1 indicating perfect evenness. The tropical forest (TF) showed a more even distribution (p < 0.043, deviation = 5.30), closer to perfect evenness, although with considerably lower abundance. The Shannon-Wiener index, sensitive to rare species (Magurran, 1988), typically ranges from 1.5 to 3.5, with higher values indicating greater diversity. 3.4.2. Similarity Index The similarity index for shared reduviid species (Table 6) revealed varying degrees of species overlap among sites within each habitat. In Godayar, sites 2 and 3 shared approximately 40% of their species, while site 3 shared no species with site 1, suggesting unique species composition at site 3. In Aralvoimozhi, sites 1 and 3 showed the highest similarity (67%). In Killikulam, the highest similarity (25.6%) was observed between sites 1 and 5, indicating lower shared diversity in this habitat. 3.4.3. Influence of Prey on Reduviid Populations Correlations between total reduviid predators and total prey populations were negative in Aralvoimozhi (r² = -0.1245), Killikulam (r² = 0.3439), and Godayar (r² = 0.5163). However, significant positive correlations were observed between individual reduviid species and specific prey insect groups. In Godayar, Rhynocoris kumarii , Cosmocludius gilvus , and Cosmocludius crocatus showed a strong positive correlation with pyrrhocorid bugs (r² = 0.924), as did Irantha armipes (r² = 0.946). Catamirus brevipennis populations were highly correlated with phytophagous hemipterans (r² = 0.92). In Killikulam, Sastrapada elongata abundance was strongly linked to weevil populations (r² = 0.962). Nabis therasii and Irantha armipes populations were associated with lepidopteran caterpillars (r² = 0.949) and Dysdercus spp. (r² = 1.0), respectively. In Aralvoimozhi, Edocla cordiger and Edocla plagiatus populations were regulated by dipterans (r² = 0.983 and r² = 0.995, respectively). 3.5. Climate Change Implications Climate change can indirectly affect reduviid populations by altering prey availability and distribution. Shifts in temperature and precipitation patterns could impact the phenology and abundance of specific prey insects, subsequently affecting the reduviid species that rely on them. Climate change leads to a decline in weevil populations in Killikulam, Sastrapada elongata populations could also be negatively impacted. Changes in the abundance and distribution of agricultural pests, influenced by climate change, could also alter the effectiveness of reduviids as biocontrol agents. Understanding the specific prey preferences of different reduviid species is crucial for predicting their responses to climate change and for developing integrated pest management strategies that consider these complex trophic interactions. 4. Discussion Documenting insect biodiversity is crucial for effective conservation (Muthupandi, 2023). This study surveyed reduviid predators across three ecotypes in the southern Western Ghats of Tamil Nadu, India, recording 641 individuals from 29 species and 7 subfamilies. The dominance of Harpactorinae and Reduviinae aligns with previous research in the region (Ambrose, 1980; Vennison, 1989; Sahayaraj, 1991; Edwin, 1997; Sivaramakrishnan, 2009) and elsewhere in India (Louis, 1973). The influence of landscape on insect population and community ecology is well-established (Hunter, 2002; Kiak, 2020; Dursun et al., 2020; Lahbib et al., 2022), a pattern also observed in this study. A weak negative correlation between reduviid bug populations and both minimum and maximum temperatures (-0.02 and − 0.03, respectively) suggests a potential sensitivity to temperature fluctuations, with population declines observed as temperatures rise (Jaya Durga et al., 2023). While previous work (Murugan, 1988; Ravichandran, 1988; Ragupathy et al., 2001; Ragupathy and Sahayaraj, 2002) reported varying levels of reduviid abundance across different habitats, including higher abundance in tropical forests, our findings indicate a contrasting pattern. We observed the highest reduviid abundance in scrub jungles (70%), followed by semi-arid zones (20%) and then tropical forests (10%). This pattern correlates with higher Shannon-Wiener (2.552), Berger-Parker (d = 0.995), and Menhinick's (Dmn = 1.490) diversity indices in the scrub jungle, suggesting that these indices are suitable metrics for assessing reduviid diversity. Simpson's and Margalef's indices, however, favored the semi-arid zone. Reduviid distribution evenness was highest in the tropical forest (E = 0.969), followed by the semi-arid zone (E = 0.686) and then the scrub jungle (E = 0.408). The similarity index revealed varying levels of species sharing among sites within each habitat, with the highest similarity observed between sites in Aralvoimozhi (scrub jungle) and the lowest in Godayar (tropical forest). The higher species richness and abundance in Aralvoimozhi, a gap in the Western Ghats characterized by moderate climatic conditions, suggests a strong influence of climate on reduviid populations. This observation aligns with Goel's (1978) findings on the importance of moderate temperature, higher humidity, and lower rainfall for hemipteran abundance, a pattern further supported by more recent research (Braschler et al., 2020, 2021). The moderate climate in Aralvoimozhi likely contributes to the thriving reduviid populations. Plant density, along with other biotic and abiotic factors, plays a significant role in insect diversity and abundance (Shah et al., 2003), exhibiting both geographic and temporal variability (Khan et al., 2021). In this study, the maximum reduviid collection occurred in July, a month characterized by low rainfall and high humidity. While Ambrose (1980) and Vennison and Ambrose (1990) emphasized the role of prey availability in regulating reduviid populations, other studies suggest a more complex interplay between prey, climate, and habitat. Vennison and Ambrose (1991) highlighted the influence of both prey and climatic factors, while Sahayaraj and Ambrose (1993) and Thanasingh and Ambrose (2006) pointed to the direct impact of abiotic factors on reduviid populations, particularly in scrub jungles and semi-arid zones. Our study did not record detailed abiotic data, limiting our ability to directly support these previous findings. However, the availability of diverse microhabitats within the forest ecosystem, as suggested by Edwin and Ambrose (1996), could buffer reduviids from the direct effects of major physical parameters like temperature and humidity. The observation that predaceous insects are often habitat specialists but feeding generalists (Boone, 2008) is also reflected in our findings. A positive correlation between reduviid populations and rainfall, as noted by Jaya Durga et al. (2023), suggests that precipitation can create favorable conditions for these insects. Ambrose's (2006) checklist of Indian reduviids documented 13 species from Aralvoimozhi, 5 from Killikulam, and 9 from Godayar. Our study adds several new records for each location: Acanthaspis pedestris , Edocla slateri , Irantha armipes , Nabis therasii , Oncocephalus annulipes , Oncocephalus notatus , Pygolampis unicolor , Rhynocoris marginatus , and Sastrapada elongata for Killikulam; A. pedestris , Acanthaspis carinata , Catamirus brevipennis , Coranus atricapillus , E. cordiger , E. plagiatus , E. slateri , E. tibialis , Endochus sp ., Harpactor melanospilus, Lisarda sp ., Microtomus picipes , Oncocephalus annulipes , Oncocephalus sp ., Peirates affinis , and Physorhincus sp . for Aralvoimozhi; and Cosmocludius crocatus, C. gilvus , Endochus sp. , Epitus bicolor , Irantha armipes , Rhaphidosoma atkinsoni , and Sycanus rectiatus for Godayar. Our findings highlight the comparatively high reduviid diversity in Aralvoimozhi, making this the first study to emphasize the rich predatory hemipteran fauna of this region within the Southern Western Ghats. The influence of abiotic factors, particularly topography, on species diversity is evident. Species specificity was observed, with A. pedestris and E. slateri primarily found in moderately dry areas (semi-arid zones and scrub jungles), suggesting limited flight adaptation. The tropical forest appears to be inhabited by some fully flying species like Sycanus rectiatus and Cosmocludius crocatus . The high reduviid abundance in the drier Aralvoimozhi region supports Sahayaraj's (2006) observation of abundant reduviid populations in dry regions with lower rainfall, humidity, and moderate temperatures. Our comprehensive survey suggests that the Southern Western Ghats, particularly Aralvoimozhi, harbors a highly diverse reduviid fauna, potentially the most diverse described to date. This study provides a valuable baseline for future research and comparative analyses of Western Ghats reduviid diversity and abundance, contributing to the conservation of this globally significant biodiversity hotspot. The observed patterns of reduviid diversity and distribution, influenced by both biotic and abiotic factors, are likely to be affected by climate change. Projected changes in temperature and precipitation could alter the suitability of different habitats for various reduviid species. Shifts in Species Distributions as temperatures rise, species like A. pedestris and E. slateri , currently found in moderately dry areas, may experience range shifts, potentially expanding into previously unsuitable areas or contracting their ranges if conditions become too extreme. The distribution of fully flying species, like Sycanus rectiatus , might also be affected by changes in wind patterns and other climatic factors. Climate change could alter the phenology and abundance of prey insects, impacting reduviid populations that rely on specific prey items. Changes in agricultural practices, influenced by climate change, could also affect pest populations and consequently, the availability of prey for reduviids in adjacent natural habitats. Changes in temperature and rainfall could alter vegetation structure and microclimate within different habitats, affecting the availability of suitable microhabitats for reduviids. Drier conditions could reduce litter cover and other ground debris, potentially limiting suitable habitat for some species. The high reduviid diversity observed in Aralvoimozhi, likely linked to its specific climatic conditions, could be particularly vulnerable to climate change. Shifts in temperature and rainfall in this region could disrupt the delicate balance that supports this rich fauna. Therefore, understanding the specific ecological requirements of different reduviid species, including their thermal tolerances, prey preferences, and microhabitat requirements, is crucial for predicting their responses to climate change. Long-term monitoring programs are essential to track changes in reduviid diversity, abundance, and distribution, providing critical information for conservation planning and management in the face of ongoing environmental changes. Further research should investigate the interactive effects of climate change and other stressors, such as habitat fragmentation and agricultural intensification, on reduviid populations in the Western Ghats. 5. Conclusion This study provides a comprehensive baseline assessment of reduviid predator diversity and distribution across three distinct habitats in the Southern Western Ghats of Tamil Nadu, India. Our findings reveal a rich reduviid fauna, with several new records for the region, and highlight the importance of scrub jungles as hotspots of reduviid diversity and abundance. The observed habitat specificity of certain reduviid species underscores the influence of environmental factors, particularly topography and associated microclimatic conditions, on their distribution. The study also suggests a complex interplay between reduviid populations, their prey, and various environmental factors. While prey availability is undoubtedly a key driver, our results indicate that other abiotic factors, perhaps acting indirectly through their influence on prey populations or microhabitat characteristics, also play a significant role. Importantly, this research establishes a crucial baseline for future studies investigating the impacts of environmental change, particularly climate change, on these important predators. The observed patterns of diversity and distribution, influenced by temperature, rainfall, and habitat structure, are likely to be affected by projected climate change scenarios. Therefore, long-term ecological monitoring of reduviid communities, coupled with research on their ecological requirements and responses to changing environmental conditions, is essential for effective conservation planning and management in the face of ongoing global change. Understanding the complex interactions between climate, habitat, and prey will be critical for predicting the future of these valuable biocontrol agents and for preserving the biodiversity of the Western Ghats. Declarations Herewith we are submitting manuscript entitled “Impact of Habitat Fragmentation on Reduviid (Hemiptera: Reduviidae) Diversity and Predation Dynamics in the Southern Western Ghats of Tamil Nadu, India” for publication in your esteemed journal. We declare that this manuscript/data, or parts thereof, has not been submitted for possible publication in another journal has not been submitted to any journals and all the authors read and approved the final manuscript. The submitted work is original and should not have been published elsewhere in any form. Acknowledgement We are grateful to D.P. Ambrose and Dr. S. Sivaraman , Entomology Research Unit, St. Xavier’s College (Autonomous), Palayamkottai, A . Venkatesh , IFS., Rd. CCF, KMTR, Tamil Nadu Forest Department and Dr. V. V. Ramamoorthy , Insect Identification Division, IARI, New Delhi. Institutional facilities were gratefully acknowledged by both ERI, Loyola College, and the Government Arts College for Men, Nanthanam. Ethical Approval : Not applicable Funding The authors declare that no funds, grants, or other support were received during the preparation of this manuscript Authors' contributions Conceptualization and methodology, M. Muthupandi; software and validation, Manimaran. A; formal analysis and investigation, Melvin A Daniel; writing—original draft preparation, M. Muthupandi; writing—review and editing, Melvin A Daniel; supervision and project administration, M. Muthupandi and Manimaran. A. All authors have read and agreed to the published version of the manuscript. Conflicts of interest/Competing interests The authors declare no conflicts of interest. References Aland S R, Mamlayya A B, Koli Y J, Bharmali D L and Bhawane G P. 2010. Studies on the heteropteran (Insecta : Heteroptera) fanuna of Amba researved forest, Western ghats, Maharashtra. The Biascon 5(3):461- 463. Ambrose DP. 1980. Bioecology and Ecophysiology and ethology of reduviids (Heteroptera) of Scrub jungles of Tamilnadu, India. Ph.D. Thesis, University of Madras, Madras. India. Ambrose DP.1999. Assasin Bugs, Science publishers. Inc. Enfield New Hampshire USA, 337 p. Ambrose DP. 2006. A checklist of Indian Assassin Bugs (Insecta: Hemiptera: Reduviidae) with taxonomic status, distribution and diagnostic morphological characteristics. Zoos' Print J. 21(9): 2388-2406. Anu A. Sabu TK and Vineesh PJ.2009. Seasonality of litter insects and relationship with rainfall in a wet evergreen forest in south Western Ghats. J. Insect Sci., 9: 46. Boone CK. Six DL and Raffa KF. 2008. The enemy of my enemy is still my enemy: competitors add to predators load of a tree-killing bark beetle. Agri. Forest Ento., 10: 441-421. https://doi.org /10.1111/j.1461-9563.2008.00402.x Braschler B. Gilgado JD. Rusterholz HP. Buchholz S. Zwahlen V and Baur B. 2021. Functional Diversity and habitat preferences of native grassland plants and gound- dwelling invertebrates in privte gardens along an urbanization gradient. Ecology and Evolution. John Wiley & Sons Ltd. DOI: 10.1002/ece3.8343 Braschler B. Gilgado JD. Zwahlen V. Rusterholz HP. Buchholz S and Baur B. 2020. Ground – dwelling invertebrate diversity in domestic garden along a rural-urban gradient: Landscape characteristic are more important than garden characteristics. PloS ONE 15 (10): e0240061. https://doi.org/10.1371/journal.pone.0240061 Christopher J. 2009. An Introduction to forest entomology, Genetics and Tree Breeding Institute, Coimbatore, India. Daniel R J R. Joshi NV and Gadil M. 1992. On the relationship between bird and woody plant species diversity in Uttara Kannada district of south India. Proc. Natl. Acad. Sci. USA 189 : pp 5311-5315. Dursun A. Fent M. 2020. First Record of the Alien Species Zelus renardii (Kolenati, 1956) (Hemiptera: Heteroptera: Reduviidae) from Black Sea Region of Turkey. J. Het. Turk., 2(2): 144-147. Dytham C. 2002. Choosing and Using Statistics: A Biologist’s Guide, Second Edition. Blackwell Publishing Company. MA. USA. Pg 68, 96. Edwin J.1997. Distribution, diversity and population dynamics of chosen insects in courtallam tropical rain forest. Ph.D. Thesis, Madurai Kamaraj University. Madurai. India. Edwin J. and Ambrose DP. 1996. Population dynamics of reduviid fauna (Insecta: Heteroptera: Reduviidae) in Courtallam tropical rainforest, Western Ghats. Biological and Cultural Control of Insect Pests, an Indian Scenario (ed.) Ambrose, D.P. Tirunelveli, India: Adeline publishers, p 94- 102. Goel S.C. 1978. Biological studies of two year capture of hemipteran in Western Utter Pradesh: Oriental Ins. 12: 369-376 . Haviland MD. 1931. The reduviidae of Kartabo, Bartica district, British Guiana. Zoologica 7: 129–154. Hunter MD. 2002. Landscape structure, habitat fragmentation, and the ecology of insects. Agri. Forest Ento., 4: 159-166. Jaya Durga. Sudarmani DNP and Sundareswari Chitharanjan. 2023. Diversity and effect of meteorological factors on the reduviid bud population from selected habitat of Viruthunagar district, Tamil Nadu, India. Intern. J. of Ento. Res. 8 (3):60-64. Kiak S. 2020. The new species invasive alien species (IAS) Zelus renardii (Kolenati, 1856) (Hemiptera: Heteroptera: Reduviidae) in central Anatolia (Turkey) J. Het. Turk . 2: 47 -52. Khan KA. Bashir MA. Mahamood R. Qadir ZA. Rafiq K. Khan MH and Ghramh HA. 2021. Foraging behavior of western honey bee ( Apis mellifera ) in different time intervals on Brassica campestries L . Fresenius. Environ. Bull. 30 (3). 2607 -2612. Kumaraswami NS and Ambrose DP. 1994. Population dynamics of assassin bugs from the Courtallam tropical evergreen forest in the Western Ghats of Tamil Nadu. J. Bombay Nat. Hist. Socie., 91 (2): 259-267. Lahbib N. Picciotti U. Sefa V. Boukhris- Bouhachen S. Porcelli F. Garganese F. 2022. Zelus renardii Roaming in Southern Italy. Insect 13(2), 158. http://doi.org/10.3390/insects13020158 Louis D. 1973. Life cycle and immature stages of Reduviidae (Hemiptera: Heteroptera) in Western Ghats. J. Ento. Soc. Nigeria 13: 1-53. Magurran AE. 1988. Ecological Diversity and its Measurement . Princeton University Press, Princeton, New Jersey. Murugan C. 1988. Biosystamatics and ecophysiology of the tibiarolite assassin bug (Heteroptera: Reduviidae) of south India, Ph.D, Thesis, Bharathiyar University, Coimbatore, India. Muthupandi M. 2023. Reduviid Diversity in Kalakad Mundanthurai Tiger Reserve, its biology and role in biological control. Ph.D. Thesis. University of Madras. Pielou EC.1975. Ecological Diversity, John Wiley and sons, New York Ragupathy E and Sahayaraj K. 2002. Diversity of reduviids predator in the semi arid zones of three southern District of Tamil Nadu, 2002, Vistas of Entomological Research for the New Millennium. pp31- 36. Ragupathy E. Subramanian K. Muthuraj B. and Ignacimuthu S. 2001. Diversity of reduviids in southern District of Tamil Nadu, J. Netcon., 13 (2): 237-244. Rajan K. and Ambrose DP. 1996. Population dynamics of three species of reduviids (Insecta: Heteroptera) in Pechiparai tropical rainforest, Western Ghats. Biological and Cultural Control of Insect Pests, an Indian Scenario (ed.) Ambrose, D.P., Tirunelveli, India: Adeline publishers, pp 138-145. Revel M. Dejean A. Céréghino R. Roux O. 2010. An Assassin among Predators: The Relationship between Plant-Ants, Their Host Myrmecophytes and the Reduviidae Zelus annulosus . PLoS ONE 5(10): e13110. doi:10.1371/journal.pone.0013110 Ravichandrean G. 1988. Biosystamatics and ecophysiology of the tibiarolite Assassin bug (Heteroptera : Reduviidae: Harpactorinae), J. Ent. Res., 13 (2): 125-127. Sahayaraj K. 1991. Bioecology and Ecophysiology and ethology of chosen predatory hemipterans and their potencial in biological control (Insecta: Heteroptera: Reduviidae) Ph.D. Thesis, Madurai Kamaraj University, Madurai. Sahayaraj K. 2006. Ecological adaptive features of Hunter Reduviids (Heteroptera: Reduviidae: Reduviidae) and their biological control In: Perspective in animal ecology and reproduction (Volume 3) (Gupta, VK and Verma AK eds.). Daya Publishing House, New Delhi. pp 22-49. Sahayaraj K and Ambrose DP. 1993. Population dynamics of Kaipothai Scrub jungles south India; J. Soil. Biol. and Ecol., 13: 122-129 . Shah PA. Brooks DR. Ashby JE. Perry JN. and Woiwod IP. 2003. Diversity and abundance of the coleopteran fauna from organic and conventional management systems in southern England. Agri. Forest Ento., 5: 51-60. Sivaramakrishnan S. 2009. Biosystematics of chosen harpactorine assassin bugs (Insecta: Hemiptera: Reduviidae). Ph.D. Thesis, Manonmaniam Sundaranar University, Tirunelveli, India. Sorennson T.1948. A method for establishing groups equal amplitude in plant sociology based on similarity of the species constant. Ect. Kong Danske. Vidensk, Selrk. Biol. Skr. (Copenhagen) 5 (4): 1-34. Thanasingh PD and Ambrose DP. 2006. Seasonal density of reduviid predators of Vagaikulam semiarid ecosystem in Thoothukudi District, Tamil Nadu. Insect Envi., 12 (1): 24 – 25. Vennison S J.1989. Bioecology and Ecophysiology and ethology of chosen Assassin bug: Ph.D. Thesis, Madurai Kamaraj University, Madurai. Vennison SJ and Ambrose DP. 1990. Population dynamics of five species of reduviids from Maruthuvazhmalai scrub jungle of southern India. Hexopoda 2: 9-14. Vennison SJ. and Ambrose DP. 1991. Population dynamics of seven species of reduviids (Insecta: Heteroptera: Reduviidae) in Muthurmalai scrub jungle from South India. J Ento. Rese., 15(3): 155-162. Tables Tables 1 to 6 are available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files MStables.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6350470","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":453333272,"identity":"ea27f9f1-3239-42be-b9d3-78e79c09ee16","order_by":0,"name":"M Muthupandi","email":"data:image/png;base64,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","orcid":"","institution":"Loyola College (Autonomous)","correspondingAuthor":true,"prefix":"","firstName":"M","middleName":"","lastName":"Muthupandi","suffix":""},{"id":453333273,"identity":"918b8db0-c697-4ee6-b873-adf1d7b87983","order_by":1,"name":"Manimaran Arokiasamy","email":"","orcid":"","institution":"Government Arts college for Men","correspondingAuthor":false,"prefix":"","firstName":"Manimaran","middleName":"","lastName":"Arokiasamy","suffix":""},{"id":453333274,"identity":"acb779fa-ac4c-4c33-9e07-26d44ded7c57","order_by":2,"name":"Melvin A Daniel","email":"","orcid":"","institution":"Loyola College (Autonomous)","correspondingAuthor":false,"prefix":"","firstName":"Melvin","middleName":"A","lastName":"Daniel","suffix":""}],"badges":[],"createdAt":"2025-04-01 07:23:09","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6350470/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6350470/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":82288621,"identity":"d87d67ff-e69b-4afc-b69c-4d01288c273d","added_by":"auto","created_at":"2025-05-08 17:01:37","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":195860,"visible":true,"origin":"","legend":"\u003cp\u003eTotal number of reduviids recorded from semi-arid zone (Killikulam), scrub jungle (Aralvoimozhi) and forest (Godayar) localities of southern Western Ghats of Tamil Nadu from September (SE) 2023 to August (AU) 2024\u003c/p\u003e","description":"","filename":"1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6350470/v1/b9c357311f5e63a516705670.jpeg"},{"id":82288623,"identity":"34e711fd-6b57-482e-ba5b-36e1003d0343","added_by":"auto","created_at":"2025-05-08 17:01:37","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":432100,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eReduviids from Aralvoimozhi, Killikulam, Godayar in different climatic conditions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ea) \u003cem\u003eRihirbus trochanders\u003c/em\u003e; b) \u003cem\u003eCoranus caprilesi\u003c/em\u003e; c) \u003cem\u003eBrassivola hystrix\u003c/em\u003e; d) \u003cem\u003eMacronthospis nodipus\u003c/em\u003e; e) \u003cem\u003eCydnacoris gilves\u003c/em\u003e; f) \u003cem\u003eEuagoras plagiatus\u003c/em\u003e; g) \u003cem\u003eAcanthopsis siva\u003c/em\u003e; h) \u003cem\u003eRhynocoris kumarii\u003c/em\u003e; i) \u003cem\u003eEpidus bicolor\u003c/em\u003e ; j) \u003cem\u003eSycanus reclinatus; \u003c/em\u003ek) \u003cem\u003ePirates\u003c/em\u003esp. l)\u003cem\u003e Acanthaspsis pedestries \u003c/em\u003e; m)\u003cem\u003eRhynocoris trochantricus\u003c/em\u003e ; n)\u003cem\u003eEndochus albomaculatus\u003c/em\u003e; o)\u003cem\u003eRhynocoris trochantricus\u003c/em\u003e morph; p) \u003cem\u003ePanthus bimaculatus\u003c/em\u003e; q) \u003cem\u003eCatamiarus brevipennis\u003c/em\u003e ; r)\u003cem\u003eAcanthaspsis siva\u003c/em\u003e; s) \u003cem\u003eRhynocoris longifrons\u003c/em\u003e\u003c/p\u003e","description":"","filename":"2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-6350470/v1/417206f41543556d8b261a59.jpeg"},{"id":84456003,"identity":"c593bdf0-7754-403e-bb31-3c515747ba06","added_by":"auto","created_at":"2025-06-12 07:54:14","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1318754,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6350470/v1/82030e39-2727-4698-9959-339bfd4a1f6b.pdf"},{"id":82288622,"identity":"9d1d41a9-58ed-47fb-8b9e-edaea61a5b5b","added_by":"auto","created_at":"2025-05-08 17:01:37","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":45165,"visible":true,"origin":"","legend":"","description":"","filename":"MStables.docx","url":"https://assets-eu.researchsquare.com/files/rs-6350470/v1/a7fc5f8d6a89a8d382e35471.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Impact of Habitat Fragmentation on Reduviid (Hemiptera: Reduviidae) Diversity and Predation Dynamics in the Southern Western Ghats of Tamil Nadu, India","fulltext":[{"header":"1. INTRODUCTION","content":"\u003cp\u003eStudies on forest biodiversity are crucial in modern ecology, as forest ecosystems, both tropical and temperate, harbor a significant portion of global biodiversity. These populations are influenced by a complex interplay of biotic and abiotic factors, including the rapidly changing climate. While research on animal and plant communities in forests is increasing, the Western Ghats, a biodiversity hotspot, remain understudied in the context of global forest diversity, particularly concerning the impacts of climate change. This mountain range, running parallel to India's west coast, from the Tapti River to Kanyakumari, is a critical ecological zone.\u003c/p\u003e \u003cp\u003eExisting research on reduviid predator diversity and distribution in Tamil Nadu, including studies by Ambrose (1980), Venison (1989), Sahayaraj (1991), Edwin (1997), Murugan (1988), Ravichandrean (1988), and Sivaramakrishnan (2009), provides a foundation. Further afield, studies like Haviland's (1931) and Revel et al.'s (2010) work in the Guianese rainforest offer comparative insights. Reduviids (Reduviidae), a species-rich and globally prevalent insect taxon, contribute significantly to forest biodiversity and play diverse roles in ecosystem dynamics and functioning (Goel, 1978; Murugan, 1988; Ravichandran, 1988; Kumaraswami and Ambrose, 1994; Edwin and Ambrose, 1996; Rajan and Ambrose, 1996; Edwin, 1997; Daniel et al., 1992). Their role as effective predators capable of top-down biocontrol (Ambrose, 1999; Sahayaraj, 2006) is particularly important in maintaining ecological balance. Previous work has documented the distribution of various insect groups, including Psocids, Isoptera, Blattaria, Dermaptera, Diptera, Hemiptera, and Orthoptera (Anu et al., 2009), and nine heteropteran families (excluding Reduviidae) (Aland et al., 2010) in the southern Western Ghats. While valuable, these studies, along with subsequent research on reduviids in different parts of the Western Ghats (Ambrose, 1980; Venison, 1989; Sahayaraj, 1991; Edwin, 1997; Sivaramakrishnan, 2009), lack a comprehensive, range-wide assessment, especially one considering the added pressure of climate change.\u003c/p\u003e \u003cp\u003eClimate change, with its projected alterations in temperature, precipitation patterns, and extreme weather events, poses a significant threat to biodiversity, particularly in sensitive ecosystems like the Western Ghats. These changes can directly impact species distribution, abundance, and interactions, potentially disrupting ecosystem services like biocontrol. Understanding the current diversity and distribution of reduviids is crucial for establishing a baseline against which future climate-driven changes can be measured. How will shifts in temperature and rainfall affect the distribution of their prey? Will these changes favor certain reduviid species over others, leading to shifts in community composition? How will altered phenology (timing of life cycle events) affect predator-prey synchrony? These are critical questions that need to be addressed.\u003c/p\u003e \u003cp\u003eTherefore, this study aims to address this gap by conducting a comprehensive survey of reduviid fauna in a semi-arid zone, scrub jungle, and forest region of the southern Western Ghats, Tamil Nadu, India. This research not only documents the diversity and distribution of reduviids but also establishes a crucial baseline for future studies examining the impacts of climate change. Furthermore, the study estimates key biodiversity indices, including evenness and richness, providing a more nuanced understanding of community structure. By focusing on these important predators, this research contributes to a broader understanding of the biogeography, organization, and dynamics of tropical communities in the Western Ghats and informs conservation strategies in the face of ongoing environmental change.\u003c/p\u003e"},{"header":"2. MATERIALS AND METHODS","content":"\u003cp\u003e\u003cstrong\u003e2.1. Study Area and Sampling Design\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study investigated reduviid predators and their prey insects across three distinct habitat types in the southern Western Ghats of Tamil Nadu, India, from 2023 to 2024. \u0026nbsp;The selected habitats represent a gradient of environmental conditions:\u003c/p\u003e\n\u003cp\u003eSemi-Arid Zone (SAZ): The Killikulam area (Latitude N 08\u0026deg;40\u0026rsquo;54.1\u0026rdquo; to 41\u0026rsquo;25.7\u0026rdquo;; Longitude E 077\u0026deg; 51\u0026rsquo;50.4\u0026rdquo; to 52\u0026rsquo;48.3\u0026rdquo;; altitude 35\u0026ndash;55m) experiences hot, dry conditions.\u003c/p\u003e\n\u003cp\u003eScrub Jungle (SJ): The Aralvoimozhi area (Latitude N 08\u0026deg; 5\u0026rsquo;57.3\u0026rdquo; to 16\u0026rsquo; 00.3\u0026rdquo; and Longitude E 077\u0026deg; 2\u0026rsquo;16.1\u0026rdquo; to 32\u0026rsquo; 53.0\u0026rdquo;; altitude 106\u0026ndash;158m) is characterized by a mix of thorny shrubs and dry deciduous vegetation.\u003c/p\u003e\n\u003cp\u003eTropical Forest (TF): The Godayar area (Latitude N 08\u0026deg; 31\u0026rsquo; 09.2\u0026rdquo; to 32\u0026rsquo; 31.6\u0026rdquo; and Longitude E 077\u0026deg;18\u0026rsquo;35.9\u0026rdquo; to 21\u0026rsquo; 28.9\u0026rdquo;; altitude 116\u0026ndash;1299m) represents a more forested and humid environment.\u003c/p\u003e\n\u003cp\u003eTo ensure representative sampling within each habitat type, two sampling sites were randomly selected, resulting in a total of six sites (two per habitat type). \u0026nbsp;Each site consisted of a 5 x 5 m plot (following the methodology of John Christopher, 2009). \u0026nbsp;The geographical coordinates (latitude and longitude) of each sampling site were recorded using a Garmin GPS map 76. \u0026nbsp;This stratified sampling design allowed for comparisons of reduviid diversity and abundance across the different habitat types. \u0026nbsp;These habitats were selected to represent a gradient of vegetation complexity and moisture availability within the southern Western Ghats.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2. Insect Collection and Identification\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInsect sampling was conducted monthly at each of the six study sites (two per habitat type) over the period 2023-2024. \u0026nbsp; Sampling efforts targeted reduviid predators and their potential prey insects, encompassing a variety of microhabitats within each site. \u0026nbsp;These microhabitats included:\u003c/p\u003e\n\u003cp\u003eArboreal: Insects were collected from tree trunks, branches, and foliage using sweep nets and visual searches.\u003c/p\u003e\n\u003cp\u003eLitter: Leaf litter and other ground debris were carefully examined, and insects were collected using forceps and small camel hair brushes.\u003c/p\u003e\n\u003cp\u003eConcealed Habitats: In the semi-arid zone and scrub jungle, stones were lifted (following Venison, 1989, and Sahayaraj, 1991) to collect reduviids and prey found underneath. In all habitats, bark crevices and other concealed spaces were also investigated.\u003c/p\u003e\n\u003cp\u003eSampling was primarily conducted during morning and evening hours to coincide with insect activity periods. \u0026nbsp;Opportunistic collections were also made when encountering specimens outside of these regular sampling times. \u0026nbsp;Collected insects were immediately anesthetized using ethyl acetate. In the laboratory, specimens were preserved using standard dry preservation techniques. Reduviids were identified to the lowest taxonomic level possible (species or genus, as appropriate). \u0026nbsp;Other insects collected were also preserved and identified, particularly those considered potential prey items of the reduviids. \u0026nbsp;Reduviids were identified using the taxonomic keys provided (Ambrose 1980). \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3. Data analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Simpson\u0026rsquo;s index is calculated using the equation 1 (Magurran, 1988)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eD = _ {ni (ni -1)/N (N-1)} ------------------------------ (1)\u003c/p\u003e\n\u003cp\u003eWhere ni is the number of individuals in the ith species and N, the total number of individuals. Simpson\u0026rsquo;s index is usually expressed as 1- D or 1/ D, hence as D increases diversity of the community decreases.\u003c/p\u003e\n\u003cp\u003eThe Shannon index is calculated by using the formula 2:\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"494\" height=\"106\"\u003e\u003c/p\u003e\n\u003cp\u003eIn this calculation the quantity Pi is the proportion of individuals found in the ith species. Where, \u0026lsquo;P\u0026rsquo; is the proportion of the \u0026lsquo;i\u0026rsquo;th species in the community, s total number of species, in is the log with the base \u0026lsquo;e\u0026rsquo; (natural logarithm) (Pielou, 1975). The overall similarity of different localities with species diversity (Cs) was calculated using the formula 3. A modified version of Jaccard formula as suggested by Sorennson (1948) was used.\u003c/p\u003e\n\u003cp\u003eSimilarity index Cs = 2j/a+b ---------------------------- (3)\u003c/p\u003e\n\u003cp\u003eWhere j is the number of species in common to the sites, a number of species in site a and b number of species in site b. Simson\u0026rsquo; diversity index was calculated using the formula 4:\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"444\" height=\"116\"\u003e\u003c/p\u003e\n\u003cp\u003eSpecies evenness index was calculated by the formula 5:\u003c/p\u003e\n\u003cp\u003eE = H\u0026rdquo;/In s ------------------------------------------ (5)\u003c/p\u003e\n\u003cp\u003eWhere \u0026lsquo;H\u0026rsquo; is Shannon Index, In is the log with the base \u0026lsquo;e\u0026rsquo; (natural logarithm),\u0026lsquo;s\u0026rsquo; total number of species. A one-way ANOVA with a significance level set at 5 % was used to compare means between topography. If the ANOVA test was significant a post hoc analysis was performed using the Tukey Honestly significant difference test (HSDT) (SPSS, 2001). The Chi-Square test of fit test is a non-parametric test which determines if there are significant differences between two or more sets of frequencies (Dytham, 2002). The underlying assumptions of this particular test is that individuals are independent, that individuals belong to only one category, and that the test is nonparametric or there is not an assumption about the shape of the underlying distribution. A Chi-Square test was used to determine the significance between the numbers of unique species of the Reduviidae of the 2009 \u0026ndash; 2010 collection between ecotypes.\u003c/p\u003e"},{"header":"3. RESULTS","content":"\u003cp\u003e\u003cstrong\u003e3.1. Reduviid Community Structure and Habitat Associations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 641 reduviid individuals, representing eight subfamilies, were collected across the three study habitats: Reduviinae (3 species), Harpactorinae (15), Peiratinae (6), Stenopodainae (2), Emesiinae (1), Ectrichodiinae (1), Holoptilinae (1), and Salyavatinae (1). \u0026nbsp;The most prevalent species were \u003cem\u003eRhynocoris fuscipes\u0026nbsp;\u003c/em\u003eand \u003cem\u003eEdocla slateri\u003c/em\u003e (present in 50% of sampling sites), followed by \u003cem\u003eAcanthapis pedestris\u003c/em\u003e and \u003cem\u003eCatamirus brevipennis\u003c/em\u003e (44.4%), \u003cem\u003eIrantha armipes\u003c/em\u003e (39%), \u003cem\u003eRhynocoris longifrons\u003c/em\u003e, \u003cem\u003eSirthena elongata\u003c/em\u003e, and \u003cem\u003eAcanthaspis carinata\u0026nbsp;\u003c/em\u003e(33.3%).\u003c/p\u003e\n\u003cp\u003eReduviid abundance differed significantly among the habitats (ANOVA: df = 1, 9; F = 249.388; p = 0.05). \u0026nbsp;The scrub jungle (SJ) exhibited the highest abundance (70% of total individuals, n=492), comprising 22 species from 14 genera and four subfamilies (Harpactorinae, Stenopodainae, Peiratinae, Holoptilinae). \u0026nbsp;The semi-arid zone (SAZ) accounted for 20% of the total (n=107), with 13 species from 10 genera, exclusively within the Harpactorinae subfamily (ANOVA: df = 3, 7; F = 0.431; p = 0.737). \u0026nbsp;The tropical forest (TF) showed the lowest abundance (10%, n=42), also belonging only to the Harpactorinae subfamily (ANOVA: df = 3, 7; F = 0.963; p = 0.461). \u0026nbsp;These findings contrast with previous research (Ambrose, 1999, 2006), which reported higher reduviid abundance in tropical forests.\u003c/p\u003e\n\u003cp\u003eChi-square tests indicated significant differences in species composition between the SJ and SAZ (\u0026chi;\u0026sup2; = 0.00189). \u0026nbsp;Differences between TF and SJ (\u0026chi;\u0026sup2; = 0.017362) and between TF and SAZ (\u0026chi;\u0026sup2; = 0.049787) were also observed, though less pronounced.\u003c/p\u003e\n\u003cp\u003eThe observed patterns of reduviid diversity and abundance across habitats are likely to be influenced by climate change. \u0026nbsp;Projected alterations in temperature and precipitation could differentially impact each habitat, potentially leading to shifts in reduviid community structure. \u0026nbsp;Increased temperatures and reduced rainfall in the SAZ could further limit the diversity and abundance of reduviids, potentially favoring only the most tolerant species. \u0026nbsp;Changes in rainfall patterns in the SJ and TF could alter vegetation structure and prey availability, indirectly affecting reduviid populations.\u003c/p\u003e\n\u003cp\u003eShifts in the phenology of reduviids and their prey could desynchronize their life cycles, impacting predation success. \u0026nbsp;Changes in the distribution and abundance of prey insects, driven by climate change, could also have cascading effects on reduviid populations. \u0026nbsp;The contrasting patterns observed in this study compared to earlier work (Ambrose, 1999, 2006) might already reflect some subtle shifts due to ongoing climate change. \u0026nbsp;Long-term monitoring of reduviid communities is essential to disentangle the complex interactions between climate change, habitat characteristics, and species distributions, and to inform conservation management strategies for these important predators and biocontrol agents.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2.\u003c/strong\u003e \u003cstrong\u003eHabitat-Specific Reduviid Distribution and Abundance\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTropical Forest (TF) - Godayar: \u0026nbsp;The Godayar tropical forest, a high-elevation site in the Western Ghats, exhibited lower overall reduviid abundance (42 individuals, all within the Harpactorinae subfamily) but a more even species distribution (evenness, E = 0.969). \u0026nbsp;\u003cem\u003eEdocla plagiatus\u003c/em\u003e and \u003cem\u003eSycanus reclinatus\u003c/em\u003e were the dominant species, comprising 41% of the total insect collection in this habitat. \u0026nbsp;Other Harpactorinae species were present but not notably dominant.\u003c/p\u003e\n\u003cp\u003eScrub Jungle (SJ) - Aralvoimozhi: \u0026nbsp;The Aralvoimozhi scrub jungle, located near rice and floriculture agroecosystems, recorded peak reduviid populations in December 2023 (ANOVA: df = 2, 18; F = 4.274; p = 0.030) and May 2025 (ANOVA: df = 2, 18; F = 5.996; p = 0.010). Despite the proximity to agricultural areas where rice pests were observed, the dominant reduviid species in Aralvoimozhi was \u003cem\u003eAcanthapis pedestris\u003c/em\u003e (18.5%), followed by \u003cem\u003eEdocla slateri\u003c/em\u003e (14.8%) and \u003cem\u003eRhynocoris longifrons\u003c/em\u003e (13.6%) (Table 3) (Figure 2).\u003c/p\u003e\n\u003cp\u003eSemi-Arid Zone (SAZ) - Killikulam: \u0026nbsp;The Killikulam semi-arid zone, situated near the perennial Tamiraparani River and adjacent to agricultural lands cultivating crops like cotton, groundnut, castor, and cucumber, showed peak reduviid abundance in February (33 individuals) (ANOVA: df = 2, 18; F = 5.008; p = 0.010) and June (27 individuals) (ANOVA: df = 2, 18; F = 5.243; p = 0.011). \u0026nbsp;\u003cem\u003eSastrapada elongata\u003c/em\u003e (38 individuals) and \u003cem\u003eAcanthaspis carinata\u003c/em\u003e (21 individuals) were the dominant species in this habitat (Table 4) (Figure 2).\u003c/p\u003e\n\u003cp\u003eIncreased aridity in the semi-arid zone could further favor \u003cem\u003eSastrapada elongata\u003c/em\u003e and \u003cem\u003eAcanthaspis carinata\u003c/em\u003e, potentially at the expense of other species. \u0026nbsp;Shifts in rainfall patterns in the scrub jungle and tropical forest could alter vegetation structure and prey availability, leading to changes in the relative abundance of dominant reduviid species. Changes in the timing of pest outbreaks in adjacent agricultural areas, driven by climate change, could indirectly affect reduviid populations in the scrub jungle and semi-arid zone. \u0026nbsp;The availability of water resources, particularly in the semi-arid zone, could also become a limiting factor for reduviids under future climate scenarios. \u0026nbsp; Therefore, understanding the current habitat associations of reduviids is crucial for predicting their responses to climate change and for developing targeted conservation strategies. \u0026nbsp; Long-term ecological monitoring is essential to track shifts in species distributions and abundances and to assess the effectiveness of conservation efforts.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3. Seasonal Abundance of Reduviids\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFour distinct seasons characterize the southern part of Tamil Nadu: winter (January and February), summer (March to May), southwest monsoon (June to September), and southeast monsoon (October to December). \u0026nbsp;Reduviid seasonal abundance varied across the study sites. In the Killikulam semi-arid zone (SAZ), the highest reduviid population (37 individuals, representing five species) was observed during the southwest monsoon season (Figure 1). However, the relationship between season and abundance in the SAZ was not strong (r\u0026sup2; = 0.252).\u003c/p\u003e\n\u003cp\u003eThe Aralvoimozhi scrub jungle (SJ) also showed peak reduviid abundance (160 individuals, 16 species) during the southwest monsoon season (Figure 1), with a strong positive correlation between season and abundance (r\u0026sup2; = 0.829). In contrast, the Godayar tropical forest (TF) recorded the highest reduviid abundance (25 individuals, 6 species) during the summer season (Figure 1), exhibiting a very strong positive correlation (r\u0026sup2; = 0.994). \u0026nbsp;It\u0026apos;s important to note that the overall abundance in the TF was considerably lower than in the other two habitats.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4. Diversity Indices and Prey Influence on Reduviid Populations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4.1. Diversity Indices\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe scrub jungle (SJ) exhibited the highest reduviid species richness and abundance (Table 5), with a significantly high population (p \u0026lt; 0.001, deviation = 30.77) and a relatively even distribution (E = 0.408). \u0026nbsp;The semi-arid zone (SAZ) showed significantly lower reduviid abundance (p \u0026lt; 0.015, deviation = 10.71). \u0026nbsp;Evenness values range from 0 to 1, with 1 indicating perfect evenness. The tropical forest (TF) showed a more even distribution (p \u0026lt; 0.043, deviation = 5.30), closer to perfect evenness, although with considerably lower abundance. \u0026nbsp; The Shannon-Wiener index, sensitive to rare species (Magurran, 1988), typically ranges from 1.5 to 3.5, with higher values indicating greater diversity.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4.2. Similarity Index\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe similarity index for shared reduviid species (Table 6) revealed varying degrees of species overlap among sites within each habitat. In Godayar, sites 2 and 3 shared approximately 40% of their species, while site 3 shared no species with site 1, suggesting unique species composition at site 3. In Aralvoimozhi, sites 1 and 3 showed the highest similarity (67%). \u0026nbsp;In Killikulam, the highest similarity (25.6%) was observed between sites 1 and 5, indicating lower shared diversity in this habitat.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4.3. Influence of Prey on Reduviid Populations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eCorrelations between total reduviid predators and total prey populations were negative in Aralvoimozhi (r\u0026sup2; = -0.1245), Killikulam (r\u0026sup2; = 0.3439), and Godayar (r\u0026sup2; = 0.5163). However, significant positive correlations were observed between individual reduviid species and specific prey insect groups. \u0026nbsp;In Godayar, \u003cem\u003eRhynocoris kumarii\u003c/em\u003e, \u003cem\u003eCosmocludius gilvus\u003c/em\u003e, and \u003cem\u003eCosmocludius crocatus\u003c/em\u003e showed a strong positive correlation with pyrrhocorid bugs (r\u0026sup2; = 0.924), as did \u003cem\u003eIrantha armipes\u003c/em\u003e (r\u0026sup2; = 0.946). \u0026nbsp;\u003cem\u003eCatamirus brevipennis\u003c/em\u003e populations were highly correlated with phytophagous hemipterans (r\u0026sup2; = 0.92). \u0026nbsp;In Killikulam, \u003cem\u003eSastrapada elongata\u003c/em\u003e abundance was strongly linked to weevil populations (r\u0026sup2; = 0.962). \u003cem\u003eNabis therasii\u003c/em\u003e and \u003cem\u003eIrantha armipes\u003c/em\u003e populations were associated with lepidopteran caterpillars (r\u0026sup2; = 0.949) and Dysdercus spp. (r\u0026sup2; = 1.0), respectively. In Aralvoimozhi, \u003cem\u003eEdocla cordiger\u003c/em\u003e and \u003cem\u003eEdocla plagiatus\u003c/em\u003e populations were regulated by dipterans (r\u0026sup2; = 0.983 and r\u0026sup2; = 0.995, respectively).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.5. Climate Change Implications\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eClimate change can indirectly affect reduviid populations by altering prey availability and distribution. \u0026nbsp; Shifts in temperature and precipitation patterns could impact the phenology and abundance of specific prey insects, subsequently affecting the reduviid species that rely on them. \u0026nbsp;Climate change leads to a decline in weevil populations in Killikulam, \u003cem\u003eSastrapada elongata\u003c/em\u003e populations could also be negatively impacted. \u0026nbsp;Changes in the abundance and distribution of agricultural pests, influenced by climate change, could also alter the effectiveness of reduviids as biocontrol agents. \u0026nbsp;Understanding the specific prey preferences of different reduviid species is crucial for predicting their responses to climate change and for developing integrated pest management strategies that consider these complex trophic interactions. \u0026nbsp;\u003c/p\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eDocumenting insect biodiversity is crucial for effective conservation (Muthupandi, 2023). This study surveyed reduviid predators across three ecotypes in the southern Western Ghats of Tamil Nadu, India, recording 641 individuals from 29 species and 7 subfamilies. The dominance of Harpactorinae and Reduviinae aligns with previous research in the region (Ambrose, 1980; Vennison, 1989; Sahayaraj, 1991; Edwin, 1997; Sivaramakrishnan, 2009) and elsewhere in India (Louis, 1973). The influence of landscape on insect population and community ecology is well-established (Hunter, 2002; Kiak, 2020; Dursun et al., 2020; Lahbib et al., 2022), a pattern also observed in this study. A weak negative correlation between reduviid bug populations and both minimum and maximum temperatures (-0.02 and \u0026minus;\u0026thinsp;0.03, respectively) suggests a potential sensitivity to temperature fluctuations, with population declines observed as temperatures rise (Jaya Durga et al., 2023).\u003c/p\u003e \u003cp\u003eWhile previous work (Murugan, 1988; Ravichandran, 1988; Ragupathy et al., 2001; Ragupathy and Sahayaraj, 2002) reported varying levels of reduviid abundance across different habitats, including higher abundance in tropical forests, our findings indicate a contrasting pattern. We observed the highest reduviid abundance in scrub jungles (70%), followed by semi-arid zones (20%) and then tropical forests (10%). This pattern correlates with higher Shannon-Wiener (2.552), Berger-Parker (d\u0026thinsp;=\u0026thinsp;0.995), and Menhinick's (Dmn\u0026thinsp;=\u0026thinsp;1.490) diversity indices in the scrub jungle, suggesting that these indices are suitable metrics for assessing reduviid diversity. Simpson's and Margalef's indices, however, favored the semi-arid zone. Reduviid distribution evenness was highest in the tropical forest (E\u0026thinsp;=\u0026thinsp;0.969), followed by the semi-arid zone (E\u0026thinsp;=\u0026thinsp;0.686) and then the scrub jungle (E\u0026thinsp;=\u0026thinsp;0.408). The similarity index revealed varying levels of species sharing among sites within each habitat, with the highest similarity observed between sites in Aralvoimozhi (scrub jungle) and the lowest in Godayar (tropical forest).\u003c/p\u003e \u003cp\u003eThe higher species richness and abundance in Aralvoimozhi, a gap in the Western Ghats characterized by moderate climatic conditions, suggests a strong influence of climate on reduviid populations. This observation aligns with Goel's (1978) findings on the importance of moderate temperature, higher humidity, and lower rainfall for hemipteran abundance, a pattern further supported by more recent research (Braschler et al., 2020, 2021). The moderate climate in Aralvoimozhi likely contributes to the thriving reduviid populations.\u003c/p\u003e \u003cp\u003ePlant density, along with other biotic and abiotic factors, plays a significant role in insect diversity and abundance (Shah et al., 2003), exhibiting both geographic and temporal variability (Khan et al., 2021). In this study, the maximum reduviid collection occurred in July, a month characterized by low rainfall and high humidity. While Ambrose (1980) and Vennison and Ambrose (1990) emphasized the role of prey availability in regulating reduviid populations, other studies suggest a more complex interplay between prey, climate, and habitat. Vennison and Ambrose (1991) highlighted the influence of both prey and climatic factors, while Sahayaraj and Ambrose (1993) and Thanasingh and Ambrose (2006) pointed to the direct impact of abiotic factors on reduviid populations, particularly in scrub jungles and semi-arid zones. Our study did not record detailed abiotic data, limiting our ability to directly support these previous findings. However, the availability of diverse microhabitats within the forest ecosystem, as suggested by Edwin and Ambrose (1996), could buffer reduviids from the direct effects of major physical parameters like temperature and humidity. The observation that predaceous insects are often habitat specialists but feeding generalists (Boone, 2008) is also reflected in our findings. A positive correlation between reduviid populations and rainfall, as noted by Jaya Durga et al. (2023), suggests that precipitation can create favorable conditions for these insects.\u003c/p\u003e \u003cp\u003eAmbrose's (2006) checklist of Indian reduviids documented 13 species from Aralvoimozhi, 5 from Killikulam, and 9 from Godayar. Our study adds several new records for each location: \u003cem\u003eAcanthaspis pedestris\u003c/em\u003e, \u003cem\u003eEdocla slateri\u003c/em\u003e, \u003cem\u003eIrantha armipes\u003c/em\u003e, \u003cem\u003eNabis therasii\u003c/em\u003e, \u003cem\u003eOncocephalus annulipes\u003c/em\u003e, \u003cem\u003eOncocephalus notatus\u003c/em\u003e, \u003cem\u003ePygolampis unicolor\u003c/em\u003e, \u003cem\u003eRhynocoris marginatus\u003c/em\u003e, and \u003cem\u003eSastrapada elongata\u003c/em\u003e for Killikulam; \u003cem\u003eA. pedestris\u003c/em\u003e, \u003cem\u003eAcanthaspis carinata\u003c/em\u003e, \u003cem\u003eCatamirus brevipennis\u003c/em\u003e, \u003cem\u003eCoranus atricapillus\u003c/em\u003e, \u003cem\u003eE. cordiger\u003c/em\u003e, \u003cem\u003eE. plagiatus\u003c/em\u003e, \u003cem\u003eE. slateri\u003c/em\u003e, \u003cem\u003eE. tibialis\u003c/em\u003e, \u003cem\u003eEndochus sp\u003c/em\u003e., \u003cem\u003eHarpactor melanospilus, Lisarda sp\u003c/em\u003e., \u003cem\u003eMicrotomus picipes\u003c/em\u003e, \u003cem\u003eOncocephalus annulipes\u003c/em\u003e, \u003cem\u003eOncocephalus sp\u003c/em\u003e., \u003cem\u003ePeirates affinis\u003c/em\u003e, and \u003cem\u003ePhysorhincus sp\u003c/em\u003e. for Aralvoimozhi; and \u003cem\u003eCosmocludius crocatus, C. gilvus\u003c/em\u003e, \u003cem\u003eEndochus sp.\u003c/em\u003e, \u003cem\u003eEpitus bicolor\u003c/em\u003e, \u003cem\u003eIrantha armipes\u003c/em\u003e, \u003cem\u003eRhaphidosoma atkinsoni\u003c/em\u003e, and \u003cem\u003eSycanus rectiatus\u003c/em\u003e for Godayar.\u003c/p\u003e \u003cp\u003eOur findings highlight the comparatively high reduviid diversity in Aralvoimozhi, making this the first study to emphasize the rich predatory hemipteran fauna of this region within the Southern Western Ghats. The influence of abiotic factors, particularly topography, on species diversity is evident. Species specificity was observed, with \u003cem\u003eA. pedestris\u003c/em\u003e and \u003cem\u003eE. slateri\u003c/em\u003e primarily found in moderately dry areas (semi-arid zones and scrub jungles), suggesting limited flight adaptation. The tropical forest appears to be inhabited by some fully flying species like \u003cem\u003eSycanus rectiatus\u003c/em\u003e and \u003cem\u003eCosmocludius crocatus\u003c/em\u003e.\u003c/p\u003e \u003cp\u003eThe high reduviid abundance in the drier Aralvoimozhi region supports Sahayaraj's (2006) observation of abundant reduviid populations in dry regions with lower rainfall, humidity, and moderate temperatures. Our comprehensive survey suggests that the Southern Western Ghats, particularly Aralvoimozhi, harbors a highly diverse reduviid fauna, potentially the most diverse described to date. This study provides a valuable baseline for future research and comparative analyses of Western Ghats reduviid diversity and abundance, contributing to the conservation of this globally significant biodiversity hotspot.\u003c/p\u003e \u003cp\u003eThe observed patterns of reduviid diversity and distribution, influenced by both biotic and abiotic factors, are likely to be affected by climate change. Projected changes in temperature and precipitation could alter the suitability of different habitats for various reduviid species. Shifts in Species Distributions as temperatures rise, species like \u003cem\u003eA. pedestris\u003c/em\u003e and \u003cem\u003eE. slateri\u003c/em\u003e, currently found in moderately dry areas, may experience range shifts, potentially expanding into previously unsuitable areas or contracting their ranges if conditions become too extreme. The distribution of fully flying species, like \u003cem\u003eSycanus rectiatus\u003c/em\u003e, might also be affected by changes in wind patterns and other climatic factors. Climate change could alter the phenology and abundance of prey insects, impacting reduviid populations that rely on specific prey items. Changes in agricultural practices, influenced by climate change, could also affect pest populations and consequently, the availability of prey for reduviids in adjacent natural habitats.\u003c/p\u003e \u003cp\u003eChanges in temperature and rainfall could alter vegetation structure and microclimate within different habitats, affecting the availability of suitable microhabitats for reduviids. Drier conditions could reduce litter cover and other ground debris, potentially limiting suitable habitat for some species. The high reduviid diversity observed in Aralvoimozhi, likely linked to its specific climatic conditions, could be particularly vulnerable to climate change. Shifts in temperature and rainfall in this region could disrupt the delicate balance that supports this rich fauna. Therefore, understanding the specific ecological requirements of different reduviid species, including their thermal tolerances, prey preferences, and microhabitat requirements, is crucial for predicting their responses to climate change. Long-term monitoring programs are essential to track changes in reduviid diversity, abundance, and distribution, providing critical information for conservation planning and management in the face of ongoing environmental changes. Further research should investigate the interactive effects of climate change and other stressors, such as habitat fragmentation and agricultural intensification, on reduviid populations in the Western Ghats.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eThis study provides a comprehensive baseline assessment of reduviid predator diversity and distribution across three distinct habitats in the Southern Western Ghats of Tamil Nadu, India. Our findings reveal a rich reduviid fauna, with several new records for the region, and highlight the importance of scrub jungles as hotspots of reduviid diversity and abundance. The observed habitat specificity of certain reduviid species underscores the influence of environmental factors, particularly topography and associated microclimatic conditions, on their distribution. The study also suggests a complex interplay between reduviid populations, their prey, and various environmental factors. While prey availability is undoubtedly a key driver, our results indicate that other abiotic factors, perhaps acting indirectly through their influence on prey populations or microhabitat characteristics, also play a significant role. Importantly, this research establishes a crucial baseline for future studies investigating the impacts of environmental change, particularly climate change, on these important predators. The observed patterns of diversity and distribution, influenced by temperature, rainfall, and habitat structure, are likely to be affected by projected climate change scenarios. Therefore, long-term ecological monitoring of reduviid communities, coupled with research on their ecological requirements and responses to changing environmental conditions, is essential for effective conservation planning and management in the face of ongoing global change. Understanding the complex interactions between climate, habitat, and prey will be critical for predicting the future of these valuable biocontrol agents and for preserving the biodiversity of the Western Ghats.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eHerewith we are submitting manuscript entitled \u0026ldquo;Impact of Habitat Fragmentation on Reduviid (Hemiptera: Reduviidae) Diversity and Predation Dynamics in the Southern Western Ghats of Tamil Nadu, India\u0026rdquo; for publication in your esteemed journal. We declare that this manuscript/data, or parts thereof, has not been submitted for possible publication in another journal has not been submitted to any journals and all the authors read and approved the final manuscript. The submitted work is original and should not have been published elsewhere in any form.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe are grateful to \u003cstrong\u003eD.P. Ambrose\u003c/strong\u003e and Dr. \u003cstrong\u003eS. Sivaraman\u003c/strong\u003e, Entomology Research Unit, St. Xavier\u0026rsquo;s College (Autonomous), Palayamkottai, A\u003cstrong\u003e. Venkatesh\u003c/strong\u003e, IFS., Rd. CCF, KMTR, Tamil Nadu Forest Department and \u003cstrong\u003eDr. V. V. Ramamoorthy\u003c/strong\u003e, Insect Identification Division, IARI, New Delhi. Institutional facilities were gratefully acknowledged by both ERI, Loyola College, and the Government Arts College for Men, Nanthanam.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval\u003c/strong\u003e: Not applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization and methodology, M. Muthupandi; software and validation, Manimaran. A; formal analysis and investigation, Melvin A Daniel; writing\u0026mdash;original draft preparation, M. Muthupandi; writing\u0026mdash;review and editing, Melvin A Daniel; supervision and project administration, M. Muthupandi and Manimaran. A. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of interest/Competing interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflicts of interest.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAland S R, \u0026nbsp; Mamlayya A B, Koli Y J, Bharmali D L and Bhawane G P. 2010. Studies on the heteropteran (Insecta : Heteroptera) fanuna of Amba researved forest, Western ghats, Maharashtra. The Biascon 5(3):461- 463.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eAmbrose DP. 1980. Bioecology and Ecophysiology and ethology of reduviids (Heteroptera) of Scrub jungles of Tamilnadu, India. Ph.D. Thesis, University of Madras, Madras. India.\u003c/li\u003e\n \u003cli\u003eAmbrose DP.1999. Assasin Bugs, Science publishers. Inc. Enfield New \u0026nbsp;Hampshire \u0026nbsp;USA, \u0026nbsp; \u0026nbsp;337 p.\u003c/li\u003e\n \u003cli\u003eAmbrose DP. 2006. 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Population dynamics of five species of reduviids from Maruthuvazhmalai scrub jungle of southern India. Hexopoda 2: 9-14.\u003c/li\u003e\n \u003cli\u003eVennison SJ. and Ambrose DP. 1991.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003ePopulation dynamics of seven species of reduviids (Insecta: Heteroptera: Reduviidae) in Muthurmalai scrub jungle from South India. J \u0026nbsp; Ento. \u0026nbsp;Rese., 15(3): 155-162.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTables 1 to 6 are available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Reduviid predators, Climate change, diversity indices, habitat, Southern Western Ghats, biological control agent","lastPublishedDoi":"10.21203/rs.3.rs-6350470/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6350470/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eClimate change is expected to significantly impact biodiversity, including predator-prey interactions. This study investigated the distribution and diversity of reduviid predators (Reduviidae), potential biocontrol agents of agricultural and forest insect pests, across three distinct habitats in the Southern Western Ghats, Tamil Nadu, India, over 12 months. Understanding baseline diversity and distribution is crucial for predicting climate change impacts. A total of 641 individuals, representing 7 sub-families, 24 genera, and 31 species were recorded from the Killikulam semi-arid zone (SAZ), Aralvoimozhi scrub jungle (SJ), and Godayar tropical forest (TF). Species richness was highest in the SJ (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e), followed by the SAZ (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e) and TF (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e). Seasonal variations in predator populations were observed, with peaks during winter in the SAZ, summer in the SJ, and also summer in the TF. The dominant reduviid species were \u003cem\u003eEdocla slateri\u003c/em\u003e and \u003cem\u003eRhynocoris fuscipes\u003c/em\u003e (50%), followed by \u003cem\u003eAcanthapis pedestris\u003c/em\u003e and \u003cem\u003eCatamirus brevipennis\u003c/em\u003e (44.4%) and \u003cem\u003eIrantha armipes\u003c/em\u003e (38.9%). These dominant species, potentially valuable for pest management, may exhibit varying responses to changing climatic conditions. The SJ exhibited a higher Shannon-Weiner index (2.552) than Simpson\u0026rsquo;s index (0.146), indicating greater diversity. While specific prey populations appear to influence the distribution of certain reduviid species, regardless of habitat, future research should investigate how climate change-induced shifts in temperature, rainfall patterns, and prey availability might alter these relationships. This baseline data is essential for developing climate-smart conservation strategies for reduviid predators and ensuring their continued effectiveness as biocontrol agents in the face of climate change.\u003c/p\u003e","manuscriptTitle":"Impact of Habitat Fragmentation on Reduviid (Hemiptera: Reduviidae) Diversity and Predation Dynamics in the Southern Western Ghats of Tamil Nadu, India","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-08 17:01:32","doi":"10.21203/rs.3.rs-6350470/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":"72d8aa2f-a774-4625-a4e5-e0e7e7898a99","owner":[],"postedDate":"May 8th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-06-12T07:53:20+00:00","versionOfRecord":[],"versionCreatedAt":"2025-05-08 17:01:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6350470","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6350470","identity":"rs-6350470","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}