Plant-insect Interactions Research Articles

Salivary proteins potentially derived from horizontal gene transfer are critical for salivary sheath formation and other feeding processes

Herbivorous insects employ an array of salivary proteins to aid feeding. However, the mechanisms behind the recruitment and evolution of these genes to mediate plant-insect interactions remain poorly understood. Here, we report a potential horizontal gene transfer (HGT) event from bacteria to an ancestral bug of Eutrichophora. The acquired genes subsequently underwent duplications and evolved through co-option. We annotated them as horizontal-transferred, Eutrichophora-specific salivary protein (HESPs) according to their origin and function. In Riptortus pedestris (Coreoidea), all nine HESPs are secreted into plants during feeding. The RpHESP4 to RpHESP8 are recently duplicated and found to be indispensable for salivary sheath formation. Silencing of RpHESP4-8 increases the difficulty of R. pedestris in probing the soybean, and the treated insects display a decreased survivability. Although silencing the other RpHESPs does not affect the salivary sheath formation, negative effects are also observed. In Pyrrhocoris apterus (Pyrrhocoroidea), five out of six PaHESPs are secretory salivary proteins, with PaHESP3 being critical for insect survival. The PaHESP5, while important for insects, no longer functions as a salivary protein. Our results provide insight into the potential origin of insect saliva and shed light on the evolution of salivary proteins.

GC-MS-based Metabolomics Unravels Metabolites across Larval Development and Diapause of a Specialist Insect.

Plant-insect interactions are a driving force into ecosystem evolution and community dynamics. Many insect herbivores enter diapause, a developmental arrest stage in anticipation of adverse conditions, to survive and thrive through seasonal changes. Herein, we investigated the roles of medium- to non-polar metabolites during larval development and diapause in a specialist insect herbivore, Chlosyne lacinia, reared on Aldama robusta leaves. Varying metabolites were determined using gas chromatography-mass spectrometry (GC-MS)-based metabolomics. Sesquiterpenes and steroids were the main metabolites putatively identified in A. robusta leaves, whereas C. lacinia caterpillars were characterized by triterpenes, steroids, fatty acids, and long-chain alkanes. We found out that C. lacinia caterpillars biosynthesized most of the identified steroids and fatty acids from plant-derived ingested metabolites, as well as all triterpenes and long-chain alkanes. Steroids, fatty acids, and long-chain alkanes were detected across all C. lacinia instars and in diapausing caterpillars. Sesquiterpenes and triterpenes were also detected across larval development, yet they were not detected in diapausing caterpillars, which suggested that these metabolites were converted to other molecules prior to the diapause stage. Our findings shed light on the chemical content variation across C. lacinia development and diapause, providing insights into the roles of metabolites in plant-insect interactions.

Rich specialized insect damage on Pliocene leaves from the Mahuadanr Valley (India) growing under a warm climate with weak seasonality.

Plant-insect interactions play a crucial role in shaping terrestrial ecosystems, influencing abundance and distribution of plant species. In the present study, we investigated leaf-mining patterns on fossil leaves from Pliocene strata of the Mahuadanr Valley, Jharkhand, eastern India, deposited under a seasonal tropical climate, and reported complex interactions between plants and insects. We identified 11 distinct mining morphotypes. These morphotypes were mainly found on Dipterocarpaceae, Fabaceae, Lauraceae, and Moraceae; similar mining traces were also observed in the contemporary vegetation surrounding the fossil site. Although mining richness was relatively high, only 2.6% of all leaves in the fossil assemblage were mined. We compared mining richness and abundance values with previously reported values for galling. While richness was slightly lower for galling, almost 50% of all fossil leaves were galled. A literature survey on mining and galling patterns in modern vegetation suggests that there is no global explanation for richness of mining or gall-inducing insects. Thus, low nutrient availability in the ancient forest, dominance of semideciduous leaves with hard texture, and different habitats in the same forest ecosystem, such as well-drained forests and riparian stands, may all have favored different types of specialized plant-insect interactions.

Unveiling the Slippery Secrets of Saliva: Effector Proteins of Phloem-Feeding Insects.

Phloem-feeding insects include many important agricultural pests that cause crop damage globally, either through feeding-related damage or upon transmission of viruses and microbes that cause plant diseases. With genetic crop resistances being limited to most of these pests, control relies on insecticides, which are costly and damaging to the environment and to which insects can develop resistance. Like other plant parasites, phloem-feeding insects deliver effectors inside their host plants to promote susceptibility, most likely by a combination of suppressing immunity and promoting nutrient availability. The recent emergence of the effector paradigm in plant-insect interactions is highlighted by increasing availability of effector repertoires for a range of species and a broadening of our knowledge concerning effector functions. Here, we focus on recent progress made toward identification of effector repertoires from phloem-feeding insects and developments in effector biology that will advance functional characterization studies. Importantly, identification of effector activities from herbivorous insects promises to provide new avenues toward development of crop protection strategies. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Nontarget impacts of neonicotinoids on nectar-inhabiting microbes.

Plant-systemic neonicotinoid (NN) insecticides can exert non-target impacts on organisms like beneficial insects and soil microbes. NNs can affect plant microbiomes, but we know little about their effects on microbial communities that mediate plant-insect interactions, including nectar-inhabiting microbes (NIMs). Here we employed two approaches to assess the impacts of NN exposure on several NIM taxa. First, we assayed the in vitro effects of six NN compounds on NIM growth using plate assays. Second, we inoculated a standardised NIM community into the nectar of NN-treated canola (Brassica napus) and assessed microbial survival and growth after 24 h. With few exceptions, in vitro NN exposure tended to decrease bacterial growth metrics. However, themagnitude of the decrease and the NN concentrations at which effects were observed varied substantially across bacteria. Yeasts showed no consistent in vitro response to NNs. In nectar, we saw no effects of NN treatment on NIM community metrics. Rather, NIM abundance and diversity responded to inherent plant qualities like nectar volume. In conclusion, we found no evidence that NIMs respond to field-relevant NN levels in nectar within 24 h, but our study suggests that context, specifically assay methods, time and plant traits, is important in assaying the effects of NNs on microbial communities.

Ontogenetic Changes in the Feeding Behaviour of Helicoverpa armigera Larvae on Pigeonpea (Cajanus cajan) Flowers and Pods.

Despite substantial research examining caterpillar-plant interactions, changes in the feeding behaviour of lepidopteran larvae as they develop are poorly understood. In this study, we investigated ontogenetic changes in the behaviour of Helicoverpa armigera larvae feeding on reproductive structures of pigeonpea (Cajanus cajan). Specifically, we examined the preference for and avoidance of pigeonpea flowers and pods of first, second, third, and fourth instar H. armigera larvae. We also conducted a no-choice assay to compare the ability of third and fourth instar larvae to penetrate pigeonpea pod walls, which act as a physical defence against herbivory. When presented with a choice between pigeonpea pods and flowers, different instars behaved differently. First and second instar larvae largely avoided pigeonpea pods, instead feeding on flowers; third instar larvae initially avoided pods, but by 24 h, did not strongly discriminate between the structures; and fourth instars demonstrated a preference for pods. When initially placed on pods, first instars were slower than other instars to leave these structures, despite pods being suboptimal feeding sites for small caterpillars. We identified a clear instar-specific ability to penetrate through the pod wall to reach the seeds. Most third instar larvae were unable to penetrate the pod wall, whereas most fourth instars succeeded. Third instars suffered a physiological cost (measured by relative growth rate) when boring through the pod wall, which was not observed in fourth instars. Our study further illuminates the insect-plant interactions of the H. armigera-pigeonpea system and provides evidence for the significant changes in feeding behaviour that may occur during lepidopteran larval development.

Recent history and future trends in host–plant resistance

Abstract Host–plant resistance (HPR) is a subdiscipline in entomology that aims to understand, develop, and deploy crop varieties resistant to arthropod herbivores. The seminal figure in HPR was Reginald Painter, whose 1951 monograph Insect Resistance in Crop Plants established a conceptual framework and methodological approach for applied research on plant resistance. In the 75 years since the publication of this book, the empirical and multidisciplinary approach established by Painter has led to the development and use of hundreds of arthropod-resistant crop varieties. Much of the success of HPR research has been, and will continue to be, tied to advances in scientific disciplines related to HPR, such as plant breeding and genetics, analytical chemistry, and plant–insect interactions. However, given the challenges facing agriculture and pest management over the coming decades, increased attention will need to be given to the deployment of resistant varieties and the integration of resistant varieties into integrated pest management (IPM) programs. Recent advances in our understanding of fundamental aspects of the interactions between plants and herbivores provide insights that can facilitate the increased use of plant resistance in IPM programs, and the diverse membership of the Entomological Society of America can play a critical role by increasing communication between scientists interested in applied and fundamental aspects of plant resistance to insects.

Flower‐visitor and pollen‐load data provide complementary insight into species and individual network roles

Most animal pollination results from plant–insect interactions, but how we perceive these interactions may differ with the sampling method adopted. The two most common methods are observations of visits by pollinators to plants and observations of pollen loads carried by insects. Each method could favour the detection of different species and interactions, and pollen load observations typically reveal more interactions per individual insect than visit observations. Moreover, while observations concern plant and insect individuals, networks are frequently analysed at the level of species. Although networks constructed using visitation and pollen‐load data have occasionally been compared in relatively specialised, bee‐dominated systems, it is not known how sampling methodology will affect our perception of how species (and individuals within species) interact in a more generalist system. Here we use a Diptera‐dominated high‐Arctic plant–insect community to explore how sampling approach shapes several measures of species' interactions (focusing on specialisation), and what we can learn about how the interactions of individuals relate to those of species. We found that species degrees, interaction strengths, and species motif roles were significantly correlated across the two method‐specific versions of the network. However, absolute differences in degrees and motif roles were greater than could be explained by the greater number of interactions per individual provided by the pollen‐load data. Thus, despite the correlations between species roles in networks built using visitation and pollen‐load data, we infer that these two perspectives yield fundamentally different summaries of the ways species fit into their communities. Further, individuals' roles generally predicted the species' overall role, but high variability among individuals means that species' roles cannot be used to predict those of particular individuals. These findings emphasize the importance of adopting a dual perspective on bipartite networks, as based on the different information inherent in insect visits and pollen loads.

Biology, Diversity, Distribution, and Characterization of Brevicoryne brassicae (L.) Cabbage

This study delves into the intricate realms of Brevicoryne brassicae (L.), commonly known as the cabbage aphid, shedding light on its biology, diversity, distribution, and characterization within cabbage ecosystems. Through a comprehensive examination of these facets, we aim to unravel key insights into the life cycle, morphological variations, and geographical presence of B. brassicae, offering a nuanced understanding of its ecological significance. Utilizing a combination of field surveys, laboratory experiments, and molecular analyses, we assess the diversity of B. brassicae populations and their potential impact on cabbage crops. The study provides valuable information for pest management strategies and contributes to the broader understanding of insect-plant interactions in agricultural ecosystems.

A chromosome-scale genome of Rhus chinensis Mill. provides new insights into plant-insect interaction and gallotannins biosynthesis.

Rhus chinensis Mill., an economically valuable Anacardiaceae species, is parasitized by the galling aphid Schlechtendalia chinensis, resulting in the formation of the Chinese gallnut (CG). Here, we report a chromosomal-level genome assembly of R. chinensis, with a total size of 389.40 Mb and scaffold N50 of 23.02 Mb. Comparative genomic and transcriptome analysis revealed that the enhanced structure of CG and nutritional metabolism contribute to improving the adaptability of R. chinensis to S. chinensis by supporting CG and galling aphid growth. CG was observed to be abundant in hydrolysable tannins (HT), particularly gallotannin and its isomers. Tandem repeat clusters of dehydroquinate dehydratase/shikimate dehydrogenase (DQD/SDH) and serine carboxypeptidase-like (SCPL) and their homologs involved in HT production were determined as specific to HT-rich species. The functional differentiation of DQD/SDH tandem duplicate genes and the significant contraction in the phenylalanine ammonia-lyase (PAL) gene family contributed to the accumulation of gallic acid and HT while minimizing the production of shikimic acid, flavonoids, and condensed tannins in CG. Furthermore, we identified one UDP glucosyltransferase (UGT84A), three carboxylesterase (CXE), and six SCPL genes from conserved tandem repeat clusters that are involved in gallotannin biosynthesis and hydrolysis in CG. We then constructed a regulatory network of these genes based on co-expression and transcription factor motif analysis. Our findings provide a genomic resource for the exploration of the underlying mechanisms of plant-galling insect interaction and highlight the importance of the functional divergence of tandem duplicate genes in the accumulation of secondary metabolites.

Learning-based oviposition constancy in insects

The search for resources occupies a major part of the time and energy budget of many insects. In this context, many insects display constancy behavior, in which they learn to return to the same, predictably rewarding resource repeatedly. Flower constancy is one such behavior, where nectar-feeding insects restrict foraging visits to a few plant species, sometimes overlooking potentially better-rewarding plants. This phenomenon is well documented in multiple species and is believed to be an optimal strategy to maximize benefits, while minimizing energy and time expenditure. Oviposition constancy is a similar behavior, where insects, dependent on previous experience, restrict their visits to a few types of potential oviposition sites. In contrast to flower constancy, the prevalence of oviposition constancy and the rationale behind this behavior are relatively unknown. An improved understanding of oviposition constancy can act as a lens into the evolutionary history of local insect adaptations, it can help gauge the impact of climate change on insect plant interactions, and it can aid the design of crop-pest management strategies. In this review, we discuss the potential benefits of oviposition constancy in insects and the extent of plasticity occurring in host-plant choice for oviposition.

The angiosperm radiation played a dual role in the diversification of insects and insect pollinators

Interactions with angiosperms have been hypothesised to play a crucial role in driving diversification among insects, with a particular emphasis on pollinator insects. However, support for coevolutionary diversification in insect–plant interactions is weak. Macroevolutionary studies of insect and plant diversities support the hypothesis that angiosperms diversified after a peak in insect diversity in the Early Cretaceous. Here, we used the family-level fossil record of insects as a whole, and insect pollinator families in particular, to estimate diversification rates and the role of angiosperms on insect macroevolutionary history using a Bayesian process-based approach. We found that angiosperms played a dual role that changed through time, mitigating insect extinction in the Cretaceous and promoting insect origination in the Cenozoic, which is also recovered for insect pollinator families only. Although insects pollinated gymnosperms before the angiosperm radiation, a radiation of new pollinator lineages began as angiosperm lineages increased, particularly significant after 50 Ma. We also found that global temperature, increases in insect diversity, and spore plants were strongly correlated with origination and extinction rates, suggesting that multiple drivers influenced insect diversification and arguing for the investigation of different explanatory variables in further studies.

Communication between undamaged plants can elicit changes in volatile emissions from neighbouring plants, thereby altering their susceptibility to aphids.

Plant volatiles play an important role in intra- and interspecific plant communication, inducing direct and indirect defenses against insect pests. However, it remains unknown whether volatile interactions between undamaged cultivars alter host plant volatile emissions and their perception by insect pests. Here, we tested the effects of exposure of a spring barley, Hordeum vulgare L., cultivar, Salome, to volatiles from other cultivars: Fairytale and Anakin. We found that exposing Salome to Fairytale induced a significantly higher emission of trans-β-ocimene and two unidentified compounds compared when exposed to Anakin. Aphids were repelled at a higher concentration of trans-β-ocimene. Salome exposure to Fairytale had significant repulsive effects on aphid olfactory preference, yet not when Salome was exposed to Anakin. We demonstrate that volatile interactions between specific undamaged plants can induce changes in volatile emission by receiver plants enhancing certain compounds, which can disrupt aphid olfactory preferences. Our results highlight the significant roles of volatiles in plant-plant interactions, affecting plant-insect interactions in suppressing insect pests. This has important implications for crop protection and sustainable agriculture.

Orco mediates olfactory behavior and oviposition in the whitefly Bemisia tabaci

Chemical signals play a central role in mediating insect feeding and reproductive behavior, and serve as the primary drivers of the insect-plant interactions. The detection of chemical signals, particularly host plant volatiles, relies heavily on the insect's complex olfactory system. The Bemisia tabaci cryptic species complex is a group of globally important whitefly pests of agricultural and ornamental crops that have a wide range of host plants, but the molecular mechanism of their host plant recognition is not yet clear. In this study, the odorant coreceptor gene of the Whitefly MEAM1 cryptic species (BtOrco) was cloned. The coding sequence of BtOrco was 1413 bp in length, with seven transmembrane structural domains, and it was expressed primarily in the heads of both male and female adult whiteflies, rather than in other tissues. Knockdown of BtOrco using transgenic plant-mediated RNAi technology significantly inhibited the foraging behavior of whiteflies. This inhibition was manifested as a reduced percentage of whiteflies responding to the host plant and a prolonged foraging period. Moreover, there was a substantial suppression of egg-laying activity among adult female whiteflies. These results indicate that BtOrco has the potential to be used as a target for the design of novel active compounds for the development of environmentally friendly whitefly control strategies.

Soil microbes from conservation agriculture systems reduce growth of Bt-resistant western corn rootworm larvae

Sustainable agricultural management practices aimed at improving soil health can alter the soil microbiome, which can influence plant health and defenses against insects. The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is a major belowground pest of corn. Pest management relies heavily on the planting of transgenic crops expressing Bacillus thuringiensis (Bt) toxins. In this study, we ask how corn-WCR interactions via the soil microbiome are affected by a conservation management system (extended corn-soybean-wheat rotation with cover crops under no-till) compared with a conventional management system (corn-soybean rotation under mulch tillage and no cover crops) when combined with transgenic Bt corn. To do this, we applied soil microbes from the conservation and conventional management systems to two corn lines, one producing Bt and one non-Bt. We then reared Bt-resistant and Bt-susceptible WCR on inoculated seedlings to examine plant and insect changes in fitness. We found that Bt was effective against susceptible larvae in both soil treatments. Bt-resistant larvae were ~ 20% smaller when reared in the presence of soil microbes from the conservation management system. Thus, control of Bt-resistant WCR may be improved in a conservation system without sacrificing Bt effectiveness in susceptible insects. Comparing the microbial communities using 16S rRNA sequencing revealed that management practices influenced the microbiomes associated with the soil and the plant rhizosphere, but not WCR. Our findings suggest value for growers in utilizing conservation management practices, such as no-till and cover crops, in agricultural systems through bottom-up changes to plant–insect interactions via the soil microbiome.

Plant-insect interactions across the Triassic–Jurassic boundary in the Sichuan Basin, South China

Plants and insects are the most diverse and ecologically important organisms in the terrestrial biosphere. Their interactions are also among the richest biotic relationships, and offer significant insights into the evolution of terrestrial ecosystem complexity through the geological record. This investigation of the late Rhaetian Xujiahe and the earliest Jurassic Zhenzhuchong floral assemblages provides the first data on foliar herbivory generated by terrestrial arthropods across the Triassic–Jurassic transition in the eastern Tethys (East Asia) region. The damage types from two fossil assemblages are collectively attributed to seven functional feeding and egg-laying categories (i.e., hole feeding, margin feeding, surface feeding, skeletonization, piercing and sucking, oviposition, and galling). Most feeding strategies are spread across the major plant groups and persist through the Triassic–Jurassic boundary, with the exception of skeletonization (a category of external foliage feeding), which was restricted to the latest Triassic within dipteridacean ferns. The survey reveals that the respective frequency and diversity of interactions between plants and insects prior to and following the end-Triassic mass extinction event are almost the same, despite a substantial turnover of floral components. This suggest that insect herbivores were largely able to transfer to alternative (but commonly related) plant groups during the dramatic floristic turnover and environmental changes at the end of the Triassic. Sporadic occurrences of foliar modifications, such as marginal cusps on pinnules of Pterophyllum and prominent ridges on the rachises of some ferns and bennettites are interpreted as adaptations for defense against insect herbivores. A few differences in taxonomic composition and herbivory representation between the latest Triassic Xujiahe flora and the earliest Jurassic Zhenzhuchong flora are more likely to be related to collection and preservational biases rather than reflecting palaeoecological changes. We encourage further investigations exploring the distribution of insect damage in fossil floras from other palaeolatitudinal zones and spanning other major extinction events to develop a better understanding of terrestrial ecosystem responses to major crises in Earth’s history.

A chromosome-level genome assembly of the Rhus gall aphid Schlechtendalia chinensis provides insight into the endogenization of Parvovirus-like DNA sequences

The Rhus gall aphid, Schlechtendalia chinensis, feeds on its primary host plant Rhus chinensis to induce galls, which have economic importance in medicines and the food industry. Rhus gall aphids have a unique life cycle and are economically beneficial but there is huge gap in genomic information about this group of aphids. Schlechtendalia chinensis induces rich-tannin galls on its host plant and is emerging as a model organism for both commercial applications and applied research in the context of gall production by insects. Here, we generated a high-quality chromosome-level assembly for the S. chinensis genome, enabling the comparison between S. chinensis and non-galling aphids. The final genome assembly is 344.59 Mb with 91.71% of the assembled sequences anchored into 13 chromosomes. We predicted 15,013 genes, of which 14,582 (97.13%) coding genes were annotated, and 99% of the predicted genes were anchored to the 13 chromosomes. This assembly reveals the endogenization of parvovirus-related DNA sequences (PRDs) in the S. chinensis genome, which could play a role in environmental adaptations. We demonstrated the characterization and classification of cytochrome P450s in the genome assembly, which are functionally crucial for sap-feeding insects and have roles in detoxification and insecticide resistance. This genome assembly also revealed the whole genome duplication events in S. chinensis, which can be considered in comparative evolutionary analysis. Our work represents a reference genome for gall-forming aphids that could be used for comparative genomic studies between galling and non-galling aphids and provides the first insight into the endogenization of PRDs in the genome of galling aphids. It also provides novel genetic information for future research on gall-formation and insect-plant interactions.

Leaf traits linked to structure and palatability drive plant-insect interactions within three forested ecosystems.

Plant traits and insect herbivory have been highly studied within the modern record but only to a limited extent within the paleontological. Preservation influences what can be measured within the fossil record, but modern methods are also not compatible with paleobotanical methods. To remedy this knowledge gap, a comparable framework was created here using modern and paleobotanical methods, allowing for future comparisons within the fossil record. Insect feeding damage on selected tree species at Harvard Forest, the Smithsonian Environmental Research Center, and La Selva were characterized using the damage type system prevalent within paleobotanical studies and compared with leaf traits. Linear models and random forest analyses tested the influence of leaf traits on total, specialized, gall, and mine frequency and diversity. Structural traits like leaf dry mass per area and palatability traits, including lignin and phosphorus concentrations, are important variables affecting gall and mine damage. The significance and strength of trait-herbivory relationships varied across forest types, which is likely driven by differences in local insect populations. This work addresses the persistent gap between modern and paleoecological studies focusing on the influence of leaf traits on insect herbivory. This is important as modern climate change alters our understanding of plant-insect interactions, providing a need for contextualizing these relationships within evolutionary time. The fossil record provides information on terrestrial response to past climatic events and, thus, should be implemented when considering how to preserve biodiversity under current and future global change.

Diversity and composition of the bacterial communities associated with the Australian spittlebugs Bathyllus albicinctus and Philagra parva (Hemiptera: Aphrophoridae).

Spittlebugs and froghoppers (Hemiptera: Cercopoidea) are insects feeding on xylem, which potentially can cause significant economic damage worldwide by transmitting plant pathogenic bacteria such as Xylella fastidiosa. Australia and New Zealand are currently free from X. fastidiosa, but they are home to at least 45 native spittlebug species. Among these, the Australian natives Bathyllus albicinctus (Erichson, 1842) and Philagra parva (Donovan, 1805) are particularly widespread and can be found across southern and eastern Australia, with B. albicinctus also in New Zealand. The potential that both species might be capable of vectoring Xylella fastidiosa poses a substantial biosecurity risk if the bacterium were to invade these regions. In this study, we examined 87 spittlebug nymphs collected across 12 different host plant species, in five locations in Victoria, Australia. Our objective was to explore the factors influencing bacterial communities within and between these widespread spittlebug species, considering geographic location, insect phylogenetics, and host plant associations. We employed COI barcoding to assess insect genetic variation and 16S high throughput sequencing (HTS) metabarcoding to analyse bacterial microbiome diversity across various host plants. Our findings revealed minimal genetic divergence among spittlebug individuals in the same species, highlighting conspecificity despite conspicuous morphological divergences. On the other hand, we recorded significant variation in bacterial communities harboured by Bathyllus albicinctus nymphs feeding on different plants, even when these were collected within close proximity to each other. Therefore, host plant association appeared to shape the bacterial communities of spittlebugs more than insect genetic divergence or geographical location. These diverse bacterial communities could potentially facilitate transmission of plant pathogenic bacteria, underscoring the risk of widespread transmission among numerous plant hosts through insect-plant interactions. This study emphasizes the critical need to understand these complex interactions, particularly in the context of biosecurity.

Impact of vereda dryness on the insect herbivore diversity in adjacent cerrado areas in Brazilian Protected Areas

Unravelling the factors that influence plant-insect interactions remains a fundamental concern in terrestrial ecology. In the present study, we evaluated the impact of varying degrees of drying on cerrado areas adjacent to veredas on the species richness, abundance and composition of the insect herbivore fauna. Additionally, we examined differences in these impacts between various guilds (chewing and sucker insects) and developmental stages (adult and immature insects). The research has been performed in study areas located in three Protected Areas in Brazil. In total, we recorded 106 species of herbivorous insects across five orders (Coleoptera, Hemiptera, Hymenoptera, Lepidoptera, and Orthoptera). Hemiptera and Coleoptera stood out as the orders with the highest species diversity and individual numbers. Among the families, Cicadellidae and Curculionidae exhibited the highest richness in species and abundance of individuals. We found that richness of herbivorous insects was higher in wet zones (20.2 ± 6.5) of the veredas compared to dry zones (12.3 ± 7.5), as well as the abundance of herbivorous insects was higher in wet zones (49.4 ± 25.5) than in the dry zones (15.8 ± 7.9). Whithin insect guilds, the abundance of chewing insects was higher in wet zones (34.0 ± 13.6) than in dry zones (16.3 ± 14.8), but this difference was not observed for the diversity of sucking insects. Regarding developmental stage, immature insects exhibited higher species richness in wet zones (10.4 ± 5.0) compared to dry zones (5.3 ± 2.1), while adult insect diversity did not show differences between the studied zones. Furthermore, the species composition of herbivorous insects, various trophic guilds (chewers and suckers) and developmental stages (adults and immature insect) did not significantly differ among the zones studied within the veredas. According to our findings, herbivorous insects exhibit a preference for wet environments, which provide better conditions and higher-quality food resources for development and reproduction.