Insect Diversity Research Articles

Relationships between flower-visiting insects and forest cover in cocoa-growing landscapes in Ghana

Abstract Context Increased cocoa cultivation (Theobroma cacao) has led to the conversion of over 6 million hectares of rainforest to cocoa farmlands in West Africa. Globally, pollinator decline has been driven by land use changes. Though land use change through cocoa expansion may affect insect pollinators and, by extension, pollination services, this has rarely been assessed. Objectives Our study examined the relationships between the proportion of natural forest in the landscape (reduced primarily due to cocoa expansion) and flower-visiting insect abundance, and bee abundance, richness, diversity and community composition. The effect of pan trap type (aerial or ground) was also tested. Methods Eighteen sites were selected along a gradient of an increasing proportion of natural forests in the surrounding landscape (from 9 to 100%). Ground and aerial pan traps were deployed in each site to sample flower-visiting insects. Two sampling sessions were conducted; during the rainy season in 2021 and during the dry season in 2022. Results The abundances of Coleoptera, Hymenoptera and Hemiptera increased with increasing proportion of natural forests in the landscape, while Diptera decreased. Natural forest and trap type did not significantly influence bee abundance, species richness, and Shannon diversity. However, bee community composition differed along the forest gradient, indicating that forests and cocoa farms harbour different bee communities. Ground pan traps captured more insects (61% of 19,927 flower-visiting insects) than aerial pan traps, which was driven by the Diptera as the abundances of the other orders were not significantly related to trap type. Conclusions Preserving natural forest in cocoa-growing landscapes is important to sustain the coexistence of diverse flower-visiting insect communities owing to their differential responses to the proportions of natural forests.

Evaluating Insect Abundance and Diversity in Organic Farming using Solar and LED Light Traps for Sustainable Pest Management

Evaluating Insect Abundance and Diversity in Organic Farming using Solar and LED Light Traps for Sustainable Pest Management

Hymenoptera and biomimetic surfaces: insights and innovations.

The extraordinary adaptations that Hymenoptera (sawflies, wasps, ants, and bees) exhibit on their body surfaces has long intrigued biologists. These adaptations, which enabled the immense success of these insects in a wide range of environments and habitats, include an amazing array of specialized structures facilitating attachment, penetration of substrates, production of sound, perception of volatiles, and delivery of venoms, among others. These morphological features offer valuable insights for biomimetic and bioinspired technological advancements. Here, we explore the biomimetic potential of hymenopteran body surfaces. We highlight recent advancements and outline potential strategic pathways, evaluating their current functions and applications while suggesting promising avenues for further investigations. By studying these fascinating and biologically diverse insects, researchers could develop innovative materials and devices that replicate the efficiency and functionality of insect body structures, driving progress in medical technology, robotics, environmental monitoring, and beyond.

A global overview of insect-fern interactions and its ecological trends.

Historically, ferns have been described as underutilized by insects. However, studies have shown a diversity of insects interacting with ferns, although the evolutionary and ecological drivers of these interactions are still to be untangled. To fill these gaps, we compiled more than 100 yr of global data on insect-fern interactions from the literature comprising 374 fern and 649 insect species. With this database we assessed how fern trophic specialization, phylogenetic relationships and climate have shaped their interactions with insects. Our findings showed that interactions between ferns and insects can be explained by the phylogenetic relations among them. We observed that insect orders part of the Endopterygota clade tend to interact with similar fern species, which might be a result of the inheritance of Endopterygota ancestors probably due to phylogenetic niche conservationism. Under an ecological context, fern specialization increased with temperature, precipitation, and climatic stability. Our results show that climate might be one of the main factors explaining the spatial variation of insect-fern interactions, postulate also supported by the observed phylogenetic clustering of the studied ferns species. Our study highlights the intricate and multifaceted nature of insect-fern interactions, where evolutionary history and ecological factors converge to shape these relationships.

30 years of terrestrial insect richness patterns across elevation: What have we learned? A global meta-analysis.

Understanding elevation variation in biodiversity is a classic question in ecology and has implications for understanding climate change impacts on mountain ecosystems. While insects are the largest group of animals, the global trend in insect species richness with elevation is unknown. To date, single studies and taxa-specific syntheses have provided no single picture, finding variable patterns of insect richness with elevation. A global synthesis across systems would provide a better understanding of how insect species richness changes with elevation and the possible environmental correlates of those patterns. We used published studies of terrestrial insect elevation gradients from 1990 to 2020 to ask: How do insect species richness change with elevation, and which environmental variables best explain this relationship statistically? With 1486 sites spanning 151 species richness-elevation gradients from 80 studies from four diverse insect taxonomic groups and five biomes, we found that overall proportional richness reached a low-elevation plateau and then decreased. We also show that mean annual temperature and seasonality best explain this trend. We suggest best practices and areas of interest for the future of insect richness-elevation studies, including underrepresented groups, geographic areas, and more standardized methods.

Rapid Evolution of Host Repertoire and Geographic Range in a Young and Diverse Genus of Montane Butterflies.

Evolutionary changes in geographic distribution and larval host plants may promote the rapid diversification of montane insects, but this scenario has been rarely investigated. We studied rapid radiation of the butterfly genus Colias, which has diversified in mountain ecosystems in Eurasia, Africa, and the Americas. Based on a dataset of 150 nuclear protein-coding genetic loci and mitochondrial genomes, we constructed a time-calibrated phylogenetic tree of Colias species with broad taxon sampling. We then inferred their ancestral geographic ranges, historical diversification rates, and the evolution of host use. We found that the most recent common ancestor of Colias was likely geographically widespread and originated ~3.5 Ma. The group subsequently diversified in different regions across the world, often in tandem with geographic expansion events. No aspect of elevation was found to have a direct effect on diversification. The genus underwent a burst of diversification soon after the divergence of the Neotropical lineage, followed by an exponential decline in diversification rate toward the present. The ancestral host repertoire included the legume genera Astragalus and Trifolium but later expanded to include a wide range of Fabaceae genera and plants in more distantly related families, punctuated with periods of host range expansion and contraction. We suggest that the widespread distribution of the ancestor of all extant Colias lineages set the stage for diversification by isolation of populations that locally adapted to the various different environments they encountered, including different host plants. In this scenario, elevation is not the main driver but might have accelerated diversification by isolating populations.

Differences in sampling efficiency of each insect order in yellow pan traps with installation of flight interception windows

AbstractTo monitor insect diversity and community changes, it is necessary to select traps with a high sampling efficiency. We examined the effects of a flight interception window on a small yellow pan trap (flight interception pan; FIP). Our results showed that fewer Hymenoptera individuals were captured by the FIP than by the non‐FIP (NFIP) traps. Fewer Aculeata, Diptera and Hemiptera individuals were captured by the FIP than by the NFIP traps, whereas more Coleoptera individuals were captured by the FIP than by the NFIP traps. The flight interception window did not affect the Aculeata species composition. Considering the labor involved in attaching windows and the reduced ease of trap transport and setting, the NFIP traps are better for sampling Hymenoptera, Diptera and Hemiptera, whereas the FIP traps are better for sampling Coleoptera.

Insect biotremology—An introduction

AbstractBiotremology, officially coined in 2016, has rapidly emerged as a distinct scientific discipline, focusing on the study of substrate‐borne mechanical waves in animal communication, particularly among insects. Initially seen as a niche within bioacoustics, biotremology is now recognized for its broad significance, rivalling chemical communication in its prevalence. This special issue highlights the multidisciplinary nature of biotremology, with research spanning insect behaviour, ecology and pest management. Studies showcase advances in understanding vibrational communication across diverse insect taxa, the development of new tools for reliable playback experiments and the growing potential of biotremology in applied pest control. This collection provides a snapshot of a dynamic field in rapid expansion, pushing the boundaries of both fundamental research and practical applications.

Evaluation of the diversity and abundance of selected insect orders (Orthoptera, Hymenoptera and Coleoptera) in a wetland in Federal University Oye-Ekiti, Nigeria

This study assessed the diversity and abundance of selected insect orders (Orthoptera, Hymenoptera and Coleoptera) in a wetland at Federal University Oye-Ekiti. Insects were collected from February to April, 2022 using a combination of pitfall traps, sweep nets and active hunting methods. Arthropods were identified up to the generic level and counted monthly. A total of 3654 individuals belonging to 3 orders, 21 families and 54 species were recorded from the studied habitat. The highest relative abundance of 19.37603% was found in Odontomachus monticola (Hymenoptera: Formicidae). In this study, Hymenoptera was the most dominant order while Orthoptera was the least dominant order. The active hunting method collected the highest number of insects while the sweep net method collected the lowest number of insects. Results of the percentage distribution of insect species and individual insects revealed that for both active hunting and pitfall trap methods, the Order Hymenoptera had the highest percentage distribution while the Order Coleoptera had the lowest percentage distribution. Results of the diversity index across the collection methods revealed that the Sweep net method had the highest insect diversity and evenness (H’=2.492, 0.4317) while the Pitfall method had the lowest insect diversity and evenness (H’=1.818, 0.126). Results of one- way ANOVA showed no significant difference in species composition across habitats at a 5% probability level. This study has shown that the etlandd at Federal University Oye- Ekiti is rich in insect species with the Order Hymenoptera being the most abundant.

Biodiversity and plant-insect interactions in fragmented habitats: A systematic review

Abstract Fragmentation is threatening insect biodiversity and intricate interactions in various ecosystems. Ecological interactions – especially those involving plants and insects – are significantly impacted by fragmented habitats. Because of fragmentation, edge effects and reduced habitat connectivity and quality affect insect species diversity, abundance, behavior, movement, life cycles, and interactions with plants, e.g., pollination, herbivory, and seed distribution. To a large degree, ecosystem services or processes are mediated by these interactions. While fragmented habitats create suitable conditions for invasive alien plants (IAPs), such invasions modify native plant composition and herbivorous insect communities because they cause a decline or loss in insect biodiversity. A systematic review was conducted by reviewing eighty-eight (88) articles to gather evidence for fragmentation effects on insect biodiversity, insects’ behavior and adaptations, plant-insect interactions (i.e., pollination, herbivory, and seed dispersal), and its influence on IAP invasions. This review deduced that any change in insect community composition and diversity due to fragmentation can have cascading effects on ecosystem processes within habitats. It further contends that successful conservation and management of fragmented habitats requires an understanding of the intricate dynamics of plant-insect interactions. However, the long-term resilience and health of ecosystems can be guaranteed by supporting sustainable land use, improving connectivity, and restoring habitats. These actions may help stop and/or reduce the effects of fragmentation on insect biodiversity and support the livelihoods and well-being of millions of people.

Family-level diversity of Coleoptera (Insecta) from the Nanling Mountains and the Greater Bay Area, China

Coleoptera comprise 198 families and over 440,000 species to date, of which 143 families and over 35,000 species are known in China. Of these, only 64 families have been recorded in Guangdong Province, fewer than in Hong Kong. To investigate the insect diversity of Guangdong, numerous specimens were collected from the Nanling Mountains and the Greater Bay Area using various methods, and over 200,000 specimens of Coleoptera were assigned to families. Thus, a preliminary study of beetles at the family-level in Guangdong is carried out based on the examined specimens and historical records. An updated checklist of beetle families in Guangdong increases the number of families from 64 to 111, in which Eupsilobiidae is recorded for the first time in China and a new species, Eidoreus haizhuensis sp. nov. is described here, demonstrating the importance of persistent collecting with different methods for the study of insect diversity. Habitus images of most of the beetle families occurring in Guangdong are provided. And the updated records are compared in detail with the published records, showing that more families may potentially be found in Guangdong, requiring further field work and taxonomists working on niche groups.

Reconstructing host plant repertoire and timing of evolution of phyline plant bugs (Hemiptera, Miridae)

AbstractThe diversity of phytophagous insects is often attributed to the success of land plants in the framework of ecological speciation. Several hypotheses have been proposed to explain host plant driven insect diversification in a phylogenetic context and have mostly been explored using Lepidoptera. We posit that Miridae are a great system to examine these hypotheses because they are one of the largest primarily phytophagous insect families and include many species with narrow host repertoire. Focusing on the species‐rich Phylinae (>2700 spp.), we generate the most taxon‐rich phylogeny published to date and for the first time estimate divergence times and trace the evolution of host plant associations across the group. Focusing on two clades of oak‐associated phylines, we further examine if diversification in these insects and their hosts coincided or if the insects tracked their hosts. We find that Phylinae diverged from their orthotyline sister group before the end of the Cretaceous, tribal‐level taxa diversified throughout the Paleogene, and diversification within genera mostly occurred in the Neogene. Host plant repertoire reconstructions at the family level show transitions from stenophagy to polyphagy are more common than the reverse. We reconstructed the ancestral phyline host as ambiguous, followed by Asterales throughout most of the deep splits. Species‐level divergences in the two oak‐associated clades coincide with those in oaks, a pattern is that is consistent with the hypothesis that these plant bugs may have cospeciated with their hosts. Our study shows that Phylinae are a suitable system to further test hypotheses on ecological speciation of plants and insects but will require more robust phylogenetic hypotheses of the group.

Cicada nymph trace fossils from South American Maastrichtian paleosols

The Cretaceous was a pivotal Period in the evolution of major insect groups, including cicadas. Insect diversification led to an increased complexity in the paleosol ichnofabrics due to the emergence of chambers associated with reproductive and feeding behaviors. Therefore, any new record of trace fossils attributed to cicadas from the Cretaceous period represent a significant advancement in understanding the diversification of this group and the emergence of insect feeding chambers, throughout the geological record. This work describes the record of the ichnogenus Feoichnus attributed to feeding chambers of cicada nymphs (Hemiptera: Cicadidae) from Maastrichtian paleosols developed in floodplain deposits of The Marília Formation (Bauru Basin, Brazil). The described Feoichnus chambers are elongated, hemispherical, and upwardly concave, with a lining covering the inner surface of the wall. The inner surface exhibits thin, irregular ridges and grooves, likely associated with fine roots. Feoichnus occurs in association with Beaconites antarcticus and root traces found within the feeding chamber, it could be indicating the movement of the trace maker and the feeding chamber from one root to another. These characteristics indicate the xylem-feeding behavior of Feoichnus trace maker in accordance with extant cicada nymph ecology. The presence of Beaconites antarcticus associated with Feoichnus and rhizoliths probably represents the foraging behavior of cicada nymphs and the displacement of feeding chambers in well-drained, rooted soils. Therefore, the cicada nymph could be the trace maker of both traces representing feeding and locomotion behavior. This contribution expands the knowledge about plant–insect interactions and insect groups that compose the Cretaceous paleosols ichnofabrics from South America.

The Effect of Spinosad on the Oak Lace Bug Corythucha arcuata (Hemiptera: Tingidae)-A Preliminary Study Performed Under Laboratory Conditions.

The effect of biopesticide compound spinosad in different concentrations was tested for the first time under laboratory conditions against the rapidly spreading forest pest, oak lace bug (Corythucha arcuata, Say 1832), and its effects were compared with the synthetic pesticide lambda-cyhalothrin. These results revealed a significant effect of spinosad at 2 mL/4 L and 2 mL/2 L water concentrations against C. arcuata nymphs. The mortality rate after 3 days was similar to synthetic insecticide effects and reached 94% and 98%, respectively. Overall, it can be concluded that spinosad is an effective biological method to control oak lace bug; treatments under field conditions should consider the high diversity of other insects in oak forests.

Belowground diversity drives multifunctionality in grazing pastures on the eastern Tibetan Plateau

Livestock grazing can alter ecosystem structure, functions, and services across diverse biomes, with grazing intensity being a key factor affecting grassland function. Although the effects of grazing on plant and soil properties have been extensively studied, the effects of grazing intensity on biodiversity and ecosystem multifunctionality (EMF) remain largely unexplored. Therefore, this study addresses this gap using 28 indicator variables from a well-controlled yak grazing intensity experiment in alpine meadows on the eastern Tibetan Plateau. The results showed that aboveground diversity (calculated using plant species richness and insect diversity) exhibited a hump-shaped and significant response to increasing grazing intensity, multidiversity (whole-ecosystem biodiversity) and belowground diversity (calculated using nematode richness and microbial diversity) showed no significant response, and EMF significantly declined. Grazing decreased carbon and nitrogen cycling indices (calculated by carbon and nitrogen in plants and soils), but did not affect phosphorus cycling. Structural equation modelling indicated that EMF was directly affected by grazing intensity and belowground diversity (i.e., nematode and fungal diversity), rather than by multidiversity, aboveground diversity, and plant pathogens. Grazing-induced decreases in plant pathogens showed no direct or indirect effects on EMF but increased multidiversity and aboveground diversity. Overall, our results highlight the critical role of conserving belowground diversity in promoting and maintaining multifunctionality in grazing pastures on the Tibetan Plateau.

Aquatic insect biodiversity, water quality variables, and microplastics in the living weir freshwater ecosystem

Most Thai rivers have not yet reached "good" ecological status. Furthermore, the scientific community is deeply concerned about the existence and abundance of microplastics (MPs) in freshwater. The live weirs' river health status was assessed using water quality and a variety of aquatic insect species. The research was conducted along Khlong-La, which was compared in the absence (R1, R2) and presence of living weirs (LWs) (M71, M62, M4, and M2). In 2023, aquatic insects and water samples were gathered during two months: January (rainy season) and July (dry season). The results revealed that the six sampling sites had similar physical and chemical properties, with the exception of total dissolved solids, which varied significantly. A total of 658 aquatic insects from 25 families and 6 orders were identified. The Hydropsychidae dominated the aquatic insect fauna at the LWs locations, followed by Chironomidae, Naucoridae, and Caenidae. Ten genera were discovered at the reference site (R1), whereas 16, 21, 24, and 19 were discovered at LWs (M71, M62, M4, M2), and 16 at the reference site (R2). The results of CCA ordination revealed that the most important factors influencing aquatic insect diversity were dissolved oxygen, water temperature, pH, electrical conductivity, and ammonia nitrogen. This study suggests that because of their significant responses to environmental factors, the species richness of aquatic insects may indicate the conservation value of habitats. The BMWPTHAI score was 41, 51, 57, 58, 73, 54, and the ASPTTHAI score was 5.12, 5.10, 5.18, 5.27, 4.86, and 5.40, respectively. Shannon-Weiner diversity index (Hʼ) values were 2.059, 2.461, 2.839, 2.777, and 2.587, respectively. The results showed that the water quality was average. The physicochemical data, as well as the BMWP and ASPT, revealed that the water at the living well was slightly polluted. Furthermore, larger MPs (>500 µm) were found in the largest concentrations, in the shape of fibers, and primarily in the color violet.

Pathways for accidental biocontrol: The human-mediated dispersal of insect predators and parasitoids.

Introductions of insect predators and parasitoids for biological control are a key method for pest management. Yet in recent decades, biological control has become more strictly regulated and less frequent. Conversely, the rate of unintentional insect introductions through human activities is rising. While accidental introductions of insect natural enemies can potentially have serious ecological consequences, they are challenging to quantify as their movements go largely unobserved. We used historical border interception records collected by the US Department of Agriculture from 1913 to 2018 to describe the diversity of entomophagous insects transported unintentionally, their main introduction pathways, and trends in host specificity. There were 35,312 interceptions of insect predators and parasitoids during this period, representing 93 families from 11 orders, and 196 species from these families. Commodity associations varied, but imported plants and plant products were the main introduction pathway. Most interceptions originated with commodities imported from the Neotropical, Panamaian, and Western Palearctic regions. Among the intercepted species, 27% were found in material originating from more than one country. Two thirds of species were polyphagous host generalists. Furthermore, 25% of species had already been introduced intentionally as biological control agents internationally, and 4.6% have documented negative impacts on native biodiversity or human society. Most of the intercepted species that have not established in the United States are host generalists or have at least one known host species available. The unintentional transport of diverse natural enemy insects has the potential to cause substantial ecological impacts, both in terms of controlling pests through accidental biocontrol and disrupting native communities. Characterizing the insects being transported and their introduction pathways can inform biosecurity practices and management.

Vegetation density is the main driver of insect species richness and diversity in small private urban front gardens

Urbanisation changes natural ecosystems and vegetation to urban green spaces, and causes insect communities to experience novel challenges for survival. New evidence suggests that urban green spaces, no matter how small, can provide meaningful habitats for insects. Information on design and management of small gardens (<6 m2) in dense urban areas is still scarce. In particular, it is hardly known which garden designs provide most benefits to insects. We surveyed 65 small urban façade gardens (μ=1.7m2) in Amsterdam and The Hague in The Netherlands and measured various garden attributes that are expected to be relevant for general, flower-visiting and herbivorous insect species richness and diversity. Plant coverage and richness were the strongest predictors of insect biodiversity and species richness. We found no support for associations with native plants or garden size. Synthesis and applicationsTo strengthen insect biodiversity in the urban environment, we recommend future design of urban green spaces to focus on maximising coverage and richness of vegetation. Although there are advantages to using native species, we acknowledge that garden owners often prefer exotic species. Some of these can also affect insect diversity and abundances positively.

Diversity of ecological functions of the insect families found in Citalahab Area of Mount Halimun Salak National Park (TNGHS)

The Citalahab area of ​​Mount Halimun Salak National Park (TNGHS) contains a diversity of insects with different ecological roles. In each type of habitat there was a composition of insect ecological roles. The study aimed to determine the diversity of ecological roles of insects in forest and plantation vegetation types in the Citalahab Area of ​​the Mount Halimun Salak National Park (TNGHS). This research uses the Simple Random Sampling method using pitfall traps in randomly determined plots measuring 20 x 20 meters (5 pit fall traps) in forests and plantations, with a total of 2 plots. There were 8 orders, 36 families with ecological roles such as: disease vectors, saprophages, pollinators, pests, predators, parasitoids, fungus eaters and decomposers. Insect families that act as parasitoids and disease vectors were only found in forest vegetation types. The richness of resources found in a habitat influences the diversity of the ecological roles of the insects found in it.

Unveiling symbiotic bacterial communities in insects feeding on the latex-rich plant Ficus microcarpa.

The diversity and health of insects that feed on plants are closely related to their mutualistic symbionts and host plants. These symbiotic partners significantly influence various metabolic activities in these insects. However, the symbiotic bacterial community of toxic plant feeders still needs further characterisation. This study aims to unravel bacterial communities associated with the different species of insect representing three insect orders: Thysanoptera, Hemiptera, and Lepidoptera, along with their predicted functional role, which exclusively feeds on latex-rich plant species Ficus microcarpa. By using 16S rRNA gene high-throughput sequencing, the analysis was able to define the major alignment of the bacterial population, primarily comprising Proteobacteria, Firmicutes, Bacteroidota, Actinobacteriota, and Acidobacteriota. Significant differences in symbiotic organisms between three insect groups were discovered by the study: hemipterans had Burkholderia and Buchnera, and lepidopterans had Acinetobacter. At the same time, Pseudomonas was detected in high abundance in both lepidopteran and thysanopteran insects. Furthermore, these symbionts exhibit consistent core functions, potentially explaining how different insects can consume the same host plant. The identified core functions of symbionts open avenues for innovative approaches in utilising these relationships to develop environment-friendly solutions for pest control, with broader implications for agriculture and environmental conservation.