Insect Feeding Research Articles

Exploiting TRP channel diversity in insects: a pathway to next-generation pest management.

Transient Receptor Potential (TRP) channels, a diverse family of over 30 ion channel subtypes, are pivotal in regulating sensory perception, thermoregulation, and feeding in insects. In Drosophila melanogaster, 13 TRP channels have been identified, while Aedes aegypti and Anopheles gambiae possess 11 and 10, respectively, showcasing evolutionary adaptations to their ecological niches. This review explores recent advancements in understanding the structure, classification, and physiological functions of TRP channels, emphasizing their evolutionary divergence across Diptera, Lepidoptera, and Hymenoptera. Key TRP subfamilies, such as TRPA, TRPC, TRPM, TRPV, TRPN, and TRPP, are discussed, highlighting their roles in chemo-sensation, gustation, and stress responses. Examples include TRPA1's involvement in thermal sensing and TRPV's role in osmoregulation, critical for insect survival under fluctuating environmental conditions. The review highlights the potential of TRP channels as targets for pest control, focusing on TRP-specific insecticides like pymetrozine, afidopyrifen, and flonicamid, which impact feeding and sensory pathways. RNA interference (RNAi) techniques targeting TRP genes are highlighted as promising tools for innovative pest management. TRP channels' role in mediating thermal tolerance is particularly significant in the context of climate change, where variable temperatures challenge pest dynamics and agricultural sustainability. Understanding these mechanisms is vital for developing climate-resilient pest control strategies. The review also evaluates methodologies used in TRP channel studies, including genomic, transcriptomic, and functional assays, alongside behavioural analyses. Despite progress, challenges remain in studying TRP channels in non-model insects and elucidating their regulation. Future research should integrate multidisciplinary approaches to fully harness TRP channels for sustainable pest management.

Altered Octopamine synthesis impairs tyrosine metabolism affecting Helicoverpa armigera vitality.

Altered Octopamine synthesis impairs tyrosine metabolism affecting Helicoverpa armigera vitality.

Myosotis scorpioides L. (Boraginaceae) floral nectary: Micromorphology, fluorescence, and ultrastructure.

Myosotis scorpioides L. (Boraginaceae) floral nectary: Micromorphology, fluorescence, and ultrastructure.

The modern pattern of insect herbivory predates the advent of angiosperms by 60 My

Modern ecosystems display complex associations of plants-insects that underwent a long evolutionary process since the appearance of mid-Paleozoic vascular plants. Although several major hypotheses explain the evolution of these plant-insect associations, the initial pattern of modern insect herbivory is poorly understood. To understand the antiquity of modern patterns of terrestrial arthropod herbivory, functional feeding group-damage type (FFG-DT) data were used to analyze a 305 My interval from Late Pennsylvanian to present, in which 134 plant assemblages were used to assess turnover (replacement of some species by other species between sites) and nestedness (difference in composition when no species are replaced between sites) in pairwise comparisons of DTs. Results of beta diversity analyses indicate that the prototype pattern for modern insect herbivory was established on gymnosperm-dominated plant assemblages by late Middle Jurassic, antedating angiosperm dominance by 60 My. Turnover among plant groups and FFGs declined in earlier late Paleozoic, whereas during the later Cenozoic, nestedness generally increased. Insect feeding on gymnosperms showed one pattern of change with low turnover and high nestedness, whereas a bimodal pattern characterized angiosperms. Ferns and angiosperms exhibited less DT functional breadth (host-plant "specificity" by herbivores) than gymnosperms, reflecting major differences in links between insect herbivores and their host plants. This fundamental trophic shift is consistent with the Mid-Mesozoic Parasitoid Revolution, implying top-down control of herbivores by their consumers rather than bottom-up regulation of food sources that shaped the modern herbivory pattern. These findings provide a data-rich account of the ecological origins of modern herbivory.

Trouble follows the needy: More severe leaf herbivory in the resource‐poor temperate oak forest than in the birch forest

Abstract Plant–insect herbivore interactions are essential in shaping forest ecosystem health. The resource availability hypothesis (RAH) and the leaf economics spectrum (LES) theory predict that species in high‐resource environments tend to adopt a ‘fast’ strategy but are more susceptible to herbivory. However, this contradicts the reports of increased insect herbivory in the context of global drought intensification and hinders accurate prediction about how different plant species respond to herbivorous insect feeding. To fill this knowledge gap, we conducted an observational study in two temperate forests dominated by Quercus mongolica and Betula platyphylla in eastern China to compare their leaf herbivory patterns and explore possible mechanisms. We measured three leaf herbivory proxies (consumed leaf area, percent consumed and herbivory frequency), some leaf traits (leaf area [LA], specific leaf area [SLA], leaf water content [LWC], leaf nitrogen, phosphorus and non‐structural carbohydrate contents) and soil properties (pH, soil water content [SWC], soil organic carbon content, soil nitrogen and phosphorus contents). We found that Q. mongolica, growing in poorer soil environments with lower water and nutrient contents, experienced higher leaf herbivory than B. platyphylla. Regarding leaf traits, Q. mongolica had a higher LA and non‐structural carbohydrate content, but lower SLA, leaf nutrient and water contents, than B. platyphylla. At the leaf level, LA, rather than SLA, of both tree species was positively correlated with leaf herbivory. At the tree level, species‐specific patterns emerged, that is, leaf herbivory of B. platyphylla was positively related to LA and negatively related to leaf nitrogen and water contents and soil phosphorus content, whereas that of Q. mongolica was only positively affected by soil phosphorus content. These findings challenge the predictions of RAH and LES theory, as Q. mongolica that grows in resource‐poor soil environments with a conservative strategy suffers higher leaf herbivory than B. platyphylla, shedding some light on the proverb that trouble follows the needy. Moreover, water‐related factors (i.e. LWC and SWC) and LA showed an important effect on driving interspecific and intraspecific leaf herbivory variations here, implying that climate‐induced droughts may exacerbate herbivore pressure in temperate forests. Read the free Plain Language Summary for this article on the Journal blog.

Comparative Feeding and Defecation Behaviors of Trypanosoma cruzi-Infected and Uninfected Triatomines (Hemiptera: Reduviidae) from the Americas.

Triatomines are vectors of Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae), the agent of Chagas disease. Stercorarian transmission occurs when infectious parasites are passed in insect feces to vertebrates through the biting wound or mucosa. Defecating on hosts during or shortly after blood feeding is, therefore, critical for transmission, and delayed triatomine defecation behavior has been posited to contribute to a low incidence of human Chagas disease in the U.S. We allowed nymphal T. cruzi-infected and uninfected Triatoma gerstaeckeri (Stål, 1859) and Triatoma sanguisuga (LeConte, 1855) to interact with restrained guinea pigs and measured insect feeding and defecation events; South American Rhodnius prolixus (Stål, 1859; Latin America) served as a comparison group. In 148 trials, 40.0% of insects fed, of which 71.2% defecated. Compared to R. prolixus, T. gerstaeckeri had >9 times higher odds of feeding, and T. sanguisuga fed longer. Observations of defecation while feeding occurred across all three species. The post-feeding defecation interval (PFDI) of R. prolixus was significantly shorter (4.54 ± 2.46 min) than that of T. gerstaeckeri (9.75 ± 2.52 min) and T. sanguisuga (20.69 ± 8.98 min). Furthermore, the PFDI was shorter for TcI-infected insects compared to uninfected insects. Triatoma gerstaeckeri and T. sanguisuga are capable of stercorarian transmission, although the calculated metrics suggest they are less efficient vectors than R. prolixus.

Engineering a novel entomopathogenic strain Pseudomonas chlororaphis for efficient production of double-stranded RNAs and pest control.

RNA interference (RNAi)-based pesticides are emerging as the next generation of pest control solutions. We have previously identified Pseudomonas chlororaphis strain R3-3, which exhibits toxicity towards Plagiodera versicolora. We engineered a mutant strain derived from R3-3, named P. chlororaphis BM, through knocking out the RNase III gene and incorporating a T7 RNA polymerase expression system to boost dsRNA production. We revealed that P. chlororaphis BM produced comparable amounts of dsRNA to the strain E. coli HT115 (DE3) while maintaining its insecticidal activity. Importantly, insect feeding bioassays demonstrated that P. chlororaphis BM expressing dsRNA targeted β-Actin (encoding β-actin protein) of P. versicolora and Srp54K (encoding signal recognition particle protein 54 k) of Henosepilachna vigintioctopunctata exhibited enhanced insecticidal efficacy compared to E. coli HT115 (DE3). The development of P. chlororaphis BM, a novel dsRNA-expressing bacterium, holds promise for pest management due to its robust dsRNA production and sustained insecticidal activity. This research paves the way for leveraging biocontrol bacteria in RNAi-based pest management strategies. © 2025 Society of Chemical Industry.

A Non-Technical Introduction to Electropenetrography and its Application with Asian Citrus Psyllid as an Example

Protecting plants by targeting insect vectors of pathogenic organisms requires an intimate understanding of the biology of the insect, the pathogen, and the plant host at a spatial scale relevant to the insect. Observing insect feeding is difficult because insect mouthparts are small, and many insects insert their mouthparts deep inside plants, where we cannot see them. Electropenetrography (EPG) is the only technique that overcomes these problems. Using EPG, we can understand host-insect relationships, pesticide action, and the role of non-hosts. EPG can address ecological questions like "how do insects survive long migrations over regions devoid of known host plants?" It can also address applied questions: "will the pest feed on my new cultivar?" This light introduction to an underused key technology focuses on the Asian citrus psyllid, but EPG has great potential to improve pest management efforts for several different crops and insect vectors.

Phytohormones enhance resistance to Tenebrio molitor by regulating reactive oxygen species and phenolic metabolism in pigeon pea.

Pigeon pea is an important economic crop with medicinal and nutritional value. Unfortunately, pest infestation of leaves during postharvest storage seriously affects the quality of pigeon pea. Phytohormones play a crucial role in disease and pest defence by regulating the accumulation of specialized metabolites. Still, their impact on the postharvest storage of pigeon pea has not been reported. In this study, the physiological parameters and main phenotypes of pigeon pea leaves treated with MeJA, ABA, and GA were investigated for the first time. The activity of the antioxidant enzyme system, which eliminates reactive oxygen species, was enhanced by applying MeJA, GA, and ABA. MeJA, GA, and ABA significantly affected crown width, plant height, and relative water content in pigeon pea, respectively. Metabolomic profiling analysis identified phenolic compounds as the main differentially accumulated metabolites (DAMs). UPLC-QqQ-MS/MS identified stilbenes, flavanones, flavones, isoflavones and anthocyanins as major phenolic compounds responsive to MeJA, GA, and ABA induction. By feeding insects, it was found that the insects fed on MeJA-, ABA-, and GA-treated leaves less than on control leaves. Correlation analysis confirmed that isoflavones play an important role in this process. Moreover, the expression of key genes involved in flavonoid biosynthetic pathways and anti-insect-related genes was regulated by MeJA, GA, and ABA. Overall, this work provides a new strategy for the cultivation and storage of pigeon pea or other commercial crops and preliminarily clarifies that flavonoid metabolites under plant hormone treatment can promote plant growth and defence against insects by regulating reactive oxygen species.

A Fungal Endophyte Alters Poplar Leaf Chemistry, Deters Insect Feeding and Shapes Insect Community Assembly.

Fungal endophytes of grasses and other herbaceous plants have been known to provide plants with anti-herbivore defence compounds, but there is little information about whether the endophytes of trees also engage in such mutualisms. We investigated the influence of the endophytic fungus Cladosporium sp. on the chemical defences of black poplar (Populus nigra) trees and the consequences for feeding preference and fitness of herbivorous insects and insect community assembly. Endophyte colonisation increased both constitutive- and induced poplar defences. Generalist Lymantria dispar larvae preferred and performed better on uninfected over endophyte-infected poplar leaves, most likely due to higher concentrations of salicinoids in endophyte-inoculated leaves and the endophyte-produced alkaloid stachydrine. Under field conditions, the endophytic fungus shapes insect community assembly i. a. attracting aphids, which can excrete stachydrine. Our results show that endophytic fungi play a crucial role in the defence against insects from different feeding guilds and thereby structuring insect communities.

A bitter taste receptor liganded by oxalic acid inhibits brown planthopper feeding by promoting CREB phosphorylation via the PI3K-AKT signaling pathway.

A bitter taste receptor liganded by oxalic acid inhibits brown planthopper feeding by promoting CREB phosphorylation via the PI3K-AKT signaling pathway.

A pentatomomorpha-specific salivary protein activates plant immunity and is critical for insect feeding

The stinkbug Riptortus pedestris, notorious for inducing soybean staygreen-like syndrome, employs a range of salivary proteins to manipulate the host plant for its benefit. Here, we show that RpSP1, a salivary protein specific to Pentatomomorpha, triggers plant defense responses in multiple plant species. RpSP1 interacts with and stabilizes a HSP40 family protein GmSPIP1 and is dependent on GmSPIP1 to induce cell death. We show that a critical 22-amino acid peptide within RpSP1 acts as an intracellular insect-derived elicitor. Furthermore, RpSP1 enhances insect-feeding efficiency. The dual functionality of RpSP1 is highlighted by the significant reduction of soybean staygreen-like syndrome following its overexpression in soybean plants or knockdown in insects. Our findings elucidate the complex molecular interactions between plants and herbivores, positioning RpSP1 as a crucial target for developing advanced pest management strategies with broad implications for agricultural biology.

Comparison of DNA-based methods for the detection of meat feeding in Alphitobius diaperinus larvae

Abstract Insects are widely consumed as a source of protein, and several species of edible insects have been approved as novel foods for the European market in the last decade. The feeding of farmed animals, including edible insects, with products of animal origin is prohibited by the Transmissible Spongiform Encephalopathy (TSE) Regulation (EU) 999/2001 and the EU Animal By-Products (ABP) Regulation (EC) 1069/2009. Accordingly, methods are needed to detect and exclude insects fed on animal-derived products. Multiple tests based on the detection of DNA have been developed, but their use for the characterisation of insect-derived foods has not been assessed rigorously. Here, we compared a range of DNA-based methods for the detection of vertebrate DNA residues in edible insects. We fed larvae of the lesser mealworm (Alphitobius diaperinus) on diets containing pork and chicken meat, and analysed samples by multiplex PCR with Sanger sequencing, real-time PCR, DNA biochips, and both short-read and long-read next-generation sequencing. We present a workflow for the efficient detection of meat and/or poultry feeding in edible insects. This workflow can be used in validated food surveillance measures to protect consumers from deception and to ensure compliance with current regulations covering the feeding of edible insects.

How widespread is pollination by sexual deception of fungus gnats in Pterostylis (Orchidaceae)?

Abstract Pollination by sexual deception has evolved multiple times in the Orchidaceae, with most known cases involving male Hymenoptera as pollinators. The diverse Australasian orchid genus Pterostylis, characterized by elaborate trap flowers, contains some species pollinated by sexual deception of fungus gnats (Diptera). However, there is considerable variation in floral morphology, suggesting that additional pollination strategies or pollen vectors may be involved. Here, we test the hypothesis that sexual deception of male Diptera is taxonomically widespread by investigating the pollination systems across a representative subset spanning nine out of 10 sections and 18 Pterostylis species. We confirm four new cases of pollination by sexual deception of male fungus gnats (families Mycetophilidae, Keroplatidae, and Sciaridae) and accrued evidence for three further cases. Each of these orchids was pollinated by a single species of fungus gnat, with two species exploiting the same pollinator. Unexpectedly, we observed insect feeding behaviour on two species pollinated by sciarid gnats and phorid flies, respectively, with trace levels of sucrose detected where feeding was observed. Our results show that the sexual deception of male fungus gnats is likely to be the dominant mode of pollination in Pterostylis, although other poorly understood pollination strategies are also present.

A Novel Insect Short Neuropeptide sNPF Peptidomimetic Insecticide: Rational Design, Synthesis, and Aphicidal Activity Study.

Short neuropeptide F (sNPF) is an insect-specific neuropeptide named for its C-terminal phenylalanine. It consists of 6-19 amino acids with a conserved RLRFa structure, regulating feeding, growth, circadian rhythms, and water-salt balance in insects. Its receptor belongs to GPCR-As and binds sNPF to regulate the insect nervous system. Many research groups are evaluating sNPF for plant protection and pest control. In this study, the natural sNPF from the pea aphid (Acyrthosiphon pisum) was used as a lead compound. Five novel sNPF analogs were designed and synthesized through molecular docking and peptidomimetics, altering the N-terminal amino acid to Ser, Thr, Tyr, Leu, or Gln. Aphid bioassays showed that the analog I-3 (YLRLRFa, LC50 = 1.820 mg/L) was more active than the natural Acypi-sNPF-1 and pymetrozine. The structure-activity relationship analysis indicated that N-terminal tyrosine incorporation, combined with increased ClogP and TPSA, enhanced aphidicidal activity. Furthermore, Toxtree's toxicity predictions suggest a low risk for all compounds, and a toxicity assay conducted on the honeybee (Apis mellifera) for I-3, which exhibits high aphidicidal activity, indicates that I-3 does not pose a toxicity risk to non-target organisms. Thus, I-3 can be utilized as a selective and environmentally friendly insecticide to manage pea aphids.

Feeding Preferences and Salivary Protein Profiles of Spodoptera frugiperda on Saccharum Species.

The invasion of the fall armyworm poses substantial threats to local agricultural safety, including the sugarcane industry. Exploring the insect-resistance mechanism is crucial for breeding resistant varieties. This study selected three representative materials from the Saccharum genus─Saccharum officinarum L. (Badila), S. spp. hybrid (GT58), and Saccharum spontaneum (SES208), to investigate feeding preferences and developmental fitness of Spodoptera frugiperda. Larvae exhibited a strong preference and highest fitness parameters in Badila leaves compared to SES208. Additionally, proteomic analyses of larval saliva from insects feeding on Badila and SES208 were carried out to test the types and abundance of proteins on different hosts. Furthermore, we identified fatty acid-binding protein 1-like activates plant defense responses, while aldehyde dehydrogenase negatively suppressed plant defense response. Our findings suggest that the plasticity of salivary proteins induced by different host plants, and also offer new insights into the molecular interactions between S. frugiperda and plants.

The expansion and loss of specific olfactory genes in relatives of parasitic lice, the stored-product psocids (Psocodea: Liposcelididae)

BackgroundBooklice, belonging to the genus Liposcelis (Psocodea: Liposcelididae), commonly known as psocids, infest a wide range of stored products and are implicated in the transmission of harmful microorganisms such as fungi and bacteria. The olfactory system is critical for insect feeding and reproduction. Elucidating the molecular mechanisms of the olfactory system in booklice is crucial for developing effective control strategies. In this study, we aim to bridge this knowledge gap by leveraging the transcriptome and genome data from five Liposcelis species.ResultUsing HMMER method and manual annotation, we have identified common gene families associated with olfactory processes, including odorant binding proteins (OBPs), chemosensory proteins (CSPs), odorant receptors (ORs), ionotropic receptors (IRs), and sensory neuron membrane proteins (SNMPs). Specifically, we identified 94, 118, 26, 47, and 34 olfactory-related genes in L. bostrychophila, L. tricolor, L. entomophila, L. decolor, and L. yangi, respectively. Comparison of quantities revealed that the number of ORs and IRs in the genome is significantly higher than those identified in the transcriptome. This discrepancy may be due to the specific expression of these genes in certain tissues or their lack of expression during the experimental stage. Simultaneously, analysis of gene expression profiles across different developmental stages revealed varying periods of peak expression for olfactory-related genes. These results suggest that the identification of olfactory-related genes in booklice on a genome-wide scale is more feasible and reliable than using a transcriptome-based approach. Additionally, compared to parasitic lice, booklice possess significantly more olfactory-related genes. This increase may be due to the inability of parasitic lice to survive without a host, whereas booklice have a wide range of feeding habits and live in complex and variable environments. Furthermore, we observed that the IR gene family in L. tricolor has undergone a certain degree of amplification, which may facilitate its adaptation to diverse environmental conditions.ConclusionsWe identified olfactory-related genes of five Liposcelis species for the first time, providing valuable insights for future functional investigations into olfactory genes associated with pheromone and odorant recognition. These discoveries present promising targets for effectively managing psocid pests.

Lethal, Sublethal and Antifeedant Effects of Azadirachtin on Some Major Insect-pests: A Review

Azadirachtin, a key bioactive compound derived from the neem tree (Azadirachta indica), has gained prominence as an eco-friendly alternative for controlling insect pests, which pose significant threats to crops. It has emerged as a versatile tool in integrated pest management strategies having a multi-faceted impact on insect pests. Azadirachtin affects the development of insect pests by disrupting their growth, moulting and pupation processes, Furthermore, the antifeedant properties of azadirachtin lead to deterring of feeding in target pests,altering insect feeding habits. The potential synergies and trade-offs of utilizing azadirachtin in conjunction with other control methods could optimize its effectiveness while minimizing ecological impact.The comprehensive insights presented herein contribute to the refinement of sustainable pest control strategies, offering guidance for future research directions and the implementation of azadirachtin in environmentally conscious agricultural practices.

Comparative analysis of grape berry microbiota uncovers sour rot associates from a Maryland vineyard.

Grape sour rot (GSR) is a disease complex involving fungi and bacteria that can cause significant yield losses of susceptible varieties. It is widely spread in the eastern U.S. and other grape-growing regions globally. Previous studies suggest that damaged fruit skin and feeding insects like Drosophila spp. are required for the disease to occur. Current control strategies for the management of sour rot are not sustainable, and research on the implications of chemical management of the disease on microbiome diversity is scarce. Our aim was to: i) investigate the effect of insecticide application and netting treatment on the microbiota of GSR-susceptible and tolerant grape varieties; and ii) identify the core microbial assemblages potentially associated with grape sour rot development in Maryland. Using a combined analysis of culture-dependent and independent data, we found that microbiota diversity of healthy grape berries did not change with netting, insecticide application, and between varieties. There was a significant difference in bacterial diversity between healthy and sour rot-affected berries. Komagataeibacter was consistently associated with infected berries followed by Acetobacter and Gluconobacter. This is the first study to report the association of Komagataeibacter with GSR-infected berries. It is thus imperative to investigate its role alongside that of other identified core microbiomes in sour rot development. Candida and Pichia were also consistent genera in infected berries. Several unidentified Candida, Pichia, and other fungal species from infected berries formed the core mycobiomes and it would be worth investigating their involvement in GSR development in Mid-Atlantic vineyards.

What Veterinarians Need to Know About the Newly-Emerging Field of Insects-as-Food-and-Feed.

Over the last two decades, the insects-as-food-and-feed industry has rapidly emerged. Its growth is largely because insects require substantially less resources (water, food, and energy) to produce than traditional sources of animal protein, making it a sustainable alternative food option. As this industry continues to grow, veterinarians will likely be called upon to assist in identifying food safety concerns, assessing animal health, implementing biosecurity measures, and formulating/prescribing treatment protocols comparable to what we have seen with the honeybee industry and the institution of veterinary feed directives (VFDs). Similar to other agricultural markets, high animal densities and management practices put insects at high risk for infectious diseases. Veterinarians interested in working with these species will need to become knowledgeable regarding the diseases afflicting the feeder insect industry and how best to diagnose and treat pathogens of concern. Using the edible cricket industry as an example, this review will highlight health and production issues while drawing similarities to other traditional livestock operations. If the insects-as-feed-and-food industry is going to be viable, veterinary involvement will be essential to ensure that insects can be used as a safe source of food for all.