First autochthonous transmission of West Nile virus (WNV) lineage 2 to humans in Spain

West Nile Virus (WNV) lineage 2, primarily endemic to parts of Africa and Europe, has recently emerged as a public health concern in new geographic regions. In 2024, the first autochthonous human case of neuroinvasive disease caused by WNV lineage 2 was identified in Andalusia, Southern Spain. Molecular testing and whole-genome sequencing confirmed WNV lineage 2 as the causative agent. Phylogenetic analysis revealed a close relationship with strains circulating in Central Europe, distinct from previous WNV lineage 2 detections in Spain. Concurrently, WNV lineage 2 RNA was detected in an imperial eagle near the case location, suggesting local viral circulation. This case marks a significant shift in WNV epidemiology in Spain, where lineage 1 has historically been dominant. The findings underscore the expanding range of WNV lineage 2 and the necessity for enhanced vector surveillance, genomic monitoring, and strengthened One Health strategies to mitigate future outbreaks and protect public health.

Impacts of neonicotinoid compounds on the structure and function of Apis mellifera OBP14: Insights from SPR, ITC, multispectroscopy, and molecular modeling

Honeybees are vital for biodiversity and agricultural productivity, yet their populations are declining globally, partly due to exposure to neonicotinoid pesticides. Odorant-binding protein 14 (OBP14) plays an important role in honeybee chemosensation, but its involvement in neonicotinoid toxicity remains underexplored due to limitations in traditional fluorescence spectroscopy techniques. This gap hampers our understanding of neonicotinoid risks to honeybee health. Here, we explored the molecular interactions between OBP14 from Apis mellifera and three widely used neonicotinoids (imidacloprid, thiamethoxam, and clothianidin) using molecular modeling, surface plasmon resonance (SPR), isothermal titration calorimetry (ITC), and multispectroscopy. SPR and ITC characterized the binding affinity, specificity, and thermodynamic parameters of AmelOBP14 interacting with three neonicotinoid compounds, revealing that the binding process is spontaneous and primarily driven by hydrophobic and electrostatic interactions. Molecular modeling highlighted that phenylalanine residue Phe54, near the binding site, plays a critical role in these interactions. UV-vis absorption spectroscopy and synchronous fluorescence spectroscopy (SFS) support slight changes in the microenvironment around the aromatic amino acids of OBP14. Fourier Transform Infrared Spectroscopy (FTIR) and circular dichroism spectroscopy (CD) indicate a decrease in the α-helix content of OBP14, suggesting a change in its secondary structure, while three-dimensional (3D) fluorescence spectroscopy confirms the non-fluorescent nature of the OBP14 polypeptide backbone. The study results revealed its potential as a biomarker for pesticide risk assessment, providing important insights into the molecular mechanisms by which neonicotinoids may impair bee chemosensory function, and offering guidance for the design of safer pesticides to minimize harm to these important pollinators.

Where do all the pests go? Understanding the genomic mechanisms of crop pest dynamics during the off-season

Agroecosystems provide abundant resources to insects. However, throughout the off-season, insects must overcome resource shortages and adverse climates to survive. This off-season persistence affects pest infestations in subsequent crops or seasons. Key pest species employ diapause, migration, and local-scale dispersal to persist during the off-season. Genomic approaches have advanced our understanding of these survival mechanisms. Clock genes regulate the circadian rhythm and interact with neuropeptides and downstream pathways, such as insulin-like peptides and hormonal factors-like ecdysteroids and juvenile hormones that regulate diapause. Migrant insects must manage processes like energy metabolism, oogenesis, and flight orientation. Local-scale dispersal requires mechanisms to locate, select, and exploit the most suitable host and habitat for survival and reproduction during the off-season. Here, we present advances in genomic research on pest survival during the off-season, focusing on diapause, migration, and local-scale dispersion. Understanding these phenomena is crucial for developing and optimizing effective integrated pest management programs.

Exotic bees in urban ecosystems: establishment, impact, and potential for invasion

Native bee species decline has sparked extensive research and conservation efforts, particularly in urban areas where initiatives and interventions aim to restore native bee populations. Paradoxically, these same urban interventions may inadvertently support non-native bee species, fostering the establishment of thriving exotic populations. Exotic bees often thrive in urban environments where advantageous traits, such as cavity-nesting and high reproductive plasticity, combine with human activities that intentionally and unintentionally facilitate their introduction and spread. Although many exotic species remain benign, others may transition to invasive status, leading to competition with native bees, the spread of diseases, and interference in biodiversity assessments. This review synthesizes current knowledge on how urbanization impacts exotic bee establishment and assesses potential pathways for these species to become invasive.

Beyond the bite: how mosquito salivary proteins modulate midgut biology and malaria parasite transmission

Mosquito blood feeding is complicated by the host's hemostatic and immune responses, which remain active after ingestion, affecting blood ingestion and digestion and threatening the midgut epithelium integrity. At the bite site, mosquitoes bypass the host's hemostatic and immune defenses by injecting saliva containing bioactive molecules, such as anticoagulants and immunomodulators, which facilitate efficient blood extraction. Ingested saliva can also modulate similar responses in the blood bolus. Here, we examine current evidence on how mosquito saliva proteins modulate blood responses in the midgut and enhance Plasmodium transmission. Saliva proteins are potential transmission-blocking targets for new intervention strategies to combat mosquito-borne diseases.

Sublethal exposure to boscalid induced respiratory abnormalities and gut microbiota dysbiosis in adult zebrafish

Boscalid (BO), one of the frequently detected fungicides of succinate dehydrogenase inhibitor in water environments, has unknown effects on the respiratory function and gut health of aquatic organisms. Therefore, zebrafish were exposed to BO solutions (0.01-1.0 mg/L) for 21 days to assess its effects on zebrafish respiration and intestinal microbiota in this study. The results showed that exposure to 0.1 and 1.0 mg/L BO for 21 days resulted in zebrafish exhibiting aggregation of gill filaments, reduction of mucous cells, and significantly decreased opercular movement, linked to a marked decline in the activity of respiratory chain complex II. 16S rRNA gene sequencing revealed significant changes in the intestinal microbiota composition of zebrafish exposed to 1.0 mg/L BO. Specifically, the relative abundance of beneficial bacteria (Cetobacterium) was markedly reduced, while pathogenic bacteria (such as Ralstonia, Legionella, Acinetobacter, Escherichia/Shigella) associated with energy metabolism and immune pathways in zebrafish showed a significant increase in relative abundance. Accordingly, metagenomic functional prediction analysis further revealed the potential impact of BO-induced gut microbiota changes on energy metabolism and immune pathways in zebrafish. Furthermore, histopathological analysis of intestinal tissues revealed that exposure to BO resulted in necrosis and shedding of epithelial cells, as well as a decrease in goblet cell count, which exacerbated adverse effects on intestinal health. In conclusion, sublethal exposure to BO affects the respiratory function and intestinal health of zebrafish. Therefore, the impact of BO in aquatic environments on fish health warrants attention.

Lower Bird Evenness and Diversity Are Associated With Higher Usutu Prevalence in Culex pipiens Mosquitoes

INTRODUCTION

The mosquito-transmitted Usutu virus has spread in the last few years, becoming endemic in several areas of Europe, such as in the southern French region of the Camargue. Our aim was to study the relationships between the presence of the viral agent in Culex mosquitoes and the structure of bird communities in the context of the dilution effect.

METHODS

We carried out mosquito and bird censuses in several selected localities across a land-use gradient and screened mosquito pools for flaviviruses. We focused on exploring how host bird diversity, richness, abundance and evenness were associated with Usutu detection in Cx. pipiens.

RESULTS

Usutu virus was detected in seven pools of Cx. pipiens, and phylogenetic analysis identified Usutu lineage Africa 3, confirming its circulation. The probability of detection in mosquitoes is associated with areas with lower bird evenness and diversity but higher bird abundance and richness and higher Cx. pipiens abundances.

CONCLUSIONS

Bird evenness was the variable with the greatest explanatory power, being negatively related to the probability of detecting Usutu in Cx. pipiens, supporting a dilution effect. These results will help us better understand the relationships between bird community structure and the risk of Usutu mosquito-borne disease.

Herbivory by multiple arthropods does not hinder the attraction of natural enemies to plant volatiles: insights from a meta-analysis

Plants under herbivore attack emit herbivore-induced plant volatiles (HIPVs) that recruit natural enemies (NEs) of the herbivores for defense. The composition of HIPVs is often specific to the herbivore species, and infestation by multiple herbivore species produces a distinct volatile blend compared to single infestations, potentially influencing tritrophic interactions. Although two decades of research have investigated how multiple herbivory can affect chemically mediated tritrophic interactions, a comprehensive understanding on this topic remains elusive, as studies have shown varying results depending on the system examined. We performed a quantitative synthesis of 29 studies, extracting effect sizes from 94 experiments that assessed the olfactory preferences of NEs for HIPVs emitted from multiple-infested and single-infested plants. Our analysis revealed that multiple infestations do not affect the attractiveness of HIPVs to NEs, regardless of whether the plant is infested by nonhosts, hosts from different or the same feeding guild, the NE dietary specialization, or guild. However, specialist NEs prefer HIPVs emitted from plants with hosts even if they are infested by multiple herbivores over those infested by only a single nonhost herbivore. Our meta-analysis provides valuable insights into the complexity of chemically mediated tritrophic interactions, demonstrating that the coinfestation with nonhosts or multiple hosts do not affect attractiveness of HIPVs to NEs.

Viviparity and obligate blood feeding: tsetse flies as a unique research system to study climate change

Tsetse flies (Glossina species) are unique organisms that combine several remarkable traits: they are obligate blood feeders, serve as critical vectors for African trypanosomes, and reproduce through adenotrophic viviparity - a process in which offspring are nourished with milk-like secretions before being born live. Here, we explore how climate change will impact the physiological processes associated with live birth in tsetse. This includes considerations of how blood feeding, host-pathogen interactions, and host-symbiont dynamics are likely to be impacted by thermal shifts. The highly specialized biology of tsetse flies suggests that this system is likely to have a distinctive response to climate change. Thus, detailed empirical research into these unique features is paramount for predicting tsetse population dynamics under climate change, with caution required when generalizing from other well-studied vectors with contrasting ecology and life histories such as mosquitoes and ticks. At the same time, the reproductive biology of tsetse, as well as microbiome and feeding dynamics, allow for a powerful model to investigate climate change through the lens of pregnancy and associated physiological adaptations in an extensively researched invertebrate.

Advances in monitoring of indoor pests

Cockroaches, bed bugs, and commensal rodents are economically and medically important indoor pests. Effective detection of these pests is critical for preventing their establishment, reducing their spread, and quickly eliminating existing activity. Many types of devices have been developed to monitor these pests. They are an essential tool in an integrated pest management program, playing an important role in pest detection and management. Here, we provide an overview of the commonly used monitoring tools and novel technologies that offer effective detection and savings in labor costs.

Endocrine regulation of reproductive behaviors in insects: a comprehensive review

Insects use pheromones in a complex system of sexual communication for reproduction. Hormones, peptides, and biogenic amines are crucial regulators involved in reproductive behaviors. Despite knowledge gaps, this review shows how hormones and related molecules influence insect reproduction and highlights the intricate endocrine network that governs reproductive behaviors through diverse signaling pathways. In the future, it will be very interesting to explore not only endocrine regulation but also the impact of environmental changes on reproductive behaviors, deepening our understanding of insect reproductive processes and their adaptability.

Genetic architecture of morphological adaptation and plasticity in insects: gaps, biases, and future directions

Insects exhibit a vast array of morphological specializations. Recent eco-evo-devo studies have provided a fresh perspective into how insect morphology can respond to the environment, both plastically and adaptively. Here, we performed a systematic literature analysis to identify biases and gaps in research on the molecular mechanisms underlying insect morphological adaptation and plasticity. We found that plasticity studies are increasingly present in the literature, while adaptation studies lag behind. Additionally, we observed a disproportionate focus on a few insect orders and specific traits like wings and body size. We highlight the need to explore the broader insect diversity, including understudied groups and unexplored traits like reproductive organs, as well as utilize advanced methods to capture subtle morphological variation. Studying a wider range of species with diverse morphologies and ecological features, as well as implementing modern genome-wide tools, can reveal the full spectrum of mechanisms underlying morphological adaptation and plasticity in insects.

Chemically mediated trophic interactions of invasive herbivorous insects and their applications for monitoring and management

Introduction of invasive herbivorous insects has significantly disrupted agricultural and forest ecosystems. Sources of stimuli used for monitoring and biosurveillance tools or as the basis for management strategies involve chemically mediated interactions between the insect and key primary producers (plants) or secondary consumers (predators and parasites). While successful application of chemicals identified from these interactions has emerged for some species with a few multitrophic interactions identified, other systems remain challenging, particularly when native species share similar chemically mediated cues. Applied molecular technologies such as environmental DNA or gut content analyses can be used to gain further insight into multitrophic interactions, which could potentially lead to improved chemical mediation tools.

Multi-organ proteome reveals different nursing ability between two honeybee srocks

High royal jelly production is an adaptive reproductive investment syndrome in honey bees that enhances their nursing ability to queen bee larvae. However, the biological basis of this reproduction investment at the multi-organ level remains elusive. In this study, proteome across 11 organs of two bee stocks: high royal jelly production bees (RJBs) and Italian bees (ITBs) was compared. Our analysis revealed significant differences in protein expression profiles in brain, fat body, mandibular gland, and Malpighian tubule, highlighting their crucial roles in regulating royal jelly secretion in RJBs. The increased energy turnover, protein synthesis, and lipid synthesis observed in RJBs compared to ITBs highlight their enhanced metabolic activity, which is essential for the robust secretion of royal jelly in RJBs. The elevated abundance of major royal jelly proteins (MRJPs), hexamerins, and vitellogenin suggests their critical contributions to the nutritional and material requirement necessary for royal jelly secretion. Furthermore, the high level of vitellogenin and juvenile hormone esterase may suppress juvenile hormones, which contribute to a strong royal jelly secretion and sensitivity of RJBs to larval pheromones relative to ITBs. This comprehensive dataset contributes to a better understanding of nursing behavior and reproductive investment in honey bees. Significiance. The royal jelly secretion syndrome is a colony level social trait dominated by the intricate interplay of multiple organs. However, previous studies have primarily focused on individual organs. In this study, the proteome of 11 organs was compared between high royal jelly production bees (RJBs) and Italian bees (ITBs) to provide knowledge on how multiple organs cooperate to boost the elevated royal jelly production by RJBs. Nutrition supply was sufficient at multiple organs of RJBs when compared to ITBs, indicating that nutrition plays an essential role in boosting energy metabolism, protein and lipid synthesis, and directly contributes to the amount of royal jelly secretion. The high level of secretion of storage proteins, such as MRJPs, hex, and vitellogenin, provides sufficient nutrition and material for royal jelly secretion. Moreover, the higher levels of vitellogenin and juvenile hormone esterase may suppress juvenile hormone synthesis, and contributing to stronger sense of RJBs to larval pheromone relative to ITBs. This suggests that nutrition can influence the hormone levels and sensory abilities of RJBs nurse bees to promote their royal jelly secretion ability. The reported data provide insights into the systematic regulation strategy of honeybee nursing behavior and reproductive investment.

Warmer and brighter winters than before: Ecological and public health challenges from the expansion of the pine processionary moth (Thaumetopoea pityocampa)

Assessing the species ecological responses to ongoing climate change is a critical challenge in environmental science. Rising temperatures, particularly in winter, are altering the distribution patterns of many species, including the pine processionary moth (PPM), Thaumetopoea pityocampa (Denis & Schiffermüller, 1775). This Mediterranean species, a significant defoliator of conifers, is expanding its range northward as winter temperatures increase. The larvae of PPM also pose serious public health risks due to their ability to induce allergic reactions in humans, pets, and livestock. To better understand these ecological shifts, we calibrated three distribution models (Bayesian Additive Regression Trees, Boosted Regression Trees, and Random Forest) based on historical and modern occurrence data compiling of 1769 points, and assessed climate suitability under historical, current and future conditions. Our results show that winter minimum temperatures, summer maximum temperatures, and solar radiation significantly influence the life cycle, and shape the geographical distribution of PPM. Under current conditions, PPM could extend its range further north, but its limited flight capabilities hinder its ability to keep up with the pace of climate change. Future projections suggest continued northward expansion, although solar radiation is expected to limit the northernmost range of PPM. Certain host tree species of PPM are frequently used as ornamental plants, particularly in urban areas, which makes the careful selection of these species a potentially valuable tool for management. Our findings identify regions that are likely to become suitable for PPM colonization, where proactive measures could be implemented.

Teflubenzuron effects on springtail life history traits explained from impairment of its lipid metabolism

This study investigated how the insecticide teflubenzuron disrupts lipid metabolism in the springtail Folsomia candida, revealing significant alterations in lipid profiles. F. candida was exposed to sub-lethal concentrations of teflubenzuron (0, 0.006, 0.014, 0.035 mg a.s. kg-1 soil dry weight). Untargeted lipidomics was used to study the dynamic changes in lipid profiles in the springtail over exposure intervals of 2, 7, and 14 days exposure intervals. Teflubenzuron induced shifts in lipid profiles, affecting lipid pathways crucial for energy storage, membrane integrity, and signaling, which are essential for survival, reproduction, and stress responses in this springtail. Diacylglycerols (DG) and Triacylglycerols (TG), which play crucial roles in energy storage and lipid-mediated signaling, were substantially affected by teflubenzuron. Decreased levels of DG and TG suggest a shift in priorities from reproduction to maintenance functions, implying disruptions in cholesterol homeostasis and vitellogenesis in response to teflubenzuron exposure. Furthermore, increased levels of fatty acids and N-acylethanolamines in response to teflubenzuron exposure indicated increased energy production and potential oxidative stress, highlighting the springtails' response to pesticide exposure. Certain lipid alterations (N-palmitoylethanolamine (NAE 16:0) and N-stearoylethanolamine (NAE 18:0)), known for their anti-inflammatory properties, point towards inflammation and mitochondrial membrane remodeling (alternations in cardiolipin lipids), indicating broader impacts on physiological functions. Ether glycerophospholipids, such as lysophosphatidylethanolamine and phosphatidylethanolamine, linked to peroxisomes and the endoplasmic reticulum, underscore their potential antioxidative role in response to oxidative stress. The study shows the significance of incorporating life cycle events into ecotoxicological assessments to comprehensively understand pesticide impacts on organisms. The integration of lipidomics into environmental risk assessments offers a more informed approach to pesticide regulation and environmental stewardship.

The spatial aggregation of phytophagous insects driven by the evolution of preference for plant chemicals

Ecologists have shown considerable interest in the spatial patterns of organism distribution and the processes responsible for their formation and maintenance. The phytophagous insects typically use chemicals in plants as host-finding cues. Because nonvolatile chemicals remain near the source, the spatial structure of plant community determines the local distribution of insects. In addition, the plant chemical accumulation due to plant-plant interaction also influences the distribution of insects. In Rumex obtusifolius, for example, the production of phenolics is mediated by conspecific interaction. Rumex plants with high phenolic concentrations are preferred by the leaf beetle Gastrophysa atrocyanea, resulting in its spatial aggregation. Although this preference of beetles for nonvolatile chemicals should be beneficial in finding host plants, there is also a cost in terms of intraspecific competition among the beetles due to aggregation on certain chemical-rich hosts. To investigate the evolutionary significance of preference for nonvolatile chemicals and the ecological consequence of spatial distribution in leaf beetles, we constructed a mathematical model for the joint evolution of two preferences for plant size and chemical condition. In the model, beetles choose a resource based on the size and chemical concentrations of plants and are exposed to resource competition. Host plants accumulate the chemicals when they interact with neighboring conspecifics, and hence the level of chemical accumulation varies depending on the species composition and spatial distribution of the plant community. As a result, beetles became more sensitive to chemicals when the host species was rare and sparsely distributed in the community. The evolution of high chemical preference caused the aggregation of beetles and hence population size declined. We proposed a potential mechanism that underlies aggregated distribution in phytophagous insects, driven by the evolution of chemical preferences in response to plant community structure.

Parental and personal experience drive personality formation and individual niche diversification in group-living mites

The idea of individual niche specialization suggests that individuals should diversify in their realized niches to mitigate inter-individual conflict. We tested the hypothesis that parental and early-life diet experiences drive individual foraging specialization and animal personality formation in plant-inhabiting predatory mites Phytoseiulus persimilis and Phytoseiulus macropilis. Both species are specialized predators of herbivorous spider mites. Adult females and males, whose parents had been exposed to either prey eggs or mobile prey, and/or who themselves had experienced either eggs or mobile prey during juvenile development, were tested for their prey life stage preference, and exploration and activity patterns. Parental and/or personal experience of a given prey life stage exerted species- and sex-dependent effects on the adult predators' mean and individual foraging phenotypes, with parental plus early-life effects being the strongest. Repeatability in activity and exploration was linked to prey life stage preference, pointing at co-variation of personality formation and individualized foraging niches.

Early life imidacloprid and copper exposure affects the gut microbiome, metabolism, and learning ability of honey bees (Apis mellifera)

The pesticide imidacloprid and the heavy metal copper provide some degree of protection to plants, while at the same time causing varying degrees of damage to bees. However, few studies have investigated the negative effects of imidacloprid and copper exposure on newly emerged bees (young bees), especially when both are present in a mix. In this study, young bees were exposed to sterile sucrose solutions containing imidacloprid (10 μg/L, 100 μg/L), copper (10 mg/L, 50 mg/L), or a mix of both (10 μg/L + 10 mg/L) for 5 days to assess their gut system and behavior, with survival and dietary consumption recorded over 21 days. We found that imidacloprid and copper reduced honeybee survival, dietary intake, and learning ability, decreased gut microbiota diversity, and caused metabolic disruptions. Notably, the mix of imidacloprid and copper had a synergistic negative effect. Correlation analyses revealed that the honeybee gut microbiota influences bee immunity and behavior by regulating metabolic pathways related to ascorbate, tryptophan, and carbohydrates. Our results demonstrate that imidacloprid and copper, either alone or in a mix, alter young bee health through a complex mechanism of toxicity. These findings highlight imidacloprid and copper's negative effects on young honeybees, offering insights for future pesticide and heavy metal impact research.

Pollution and partitioning of neonicotinoid insecticides in free-grazing ducks and their eggs: Implications for human health

Neonicotinoid insecticides are used extensively in many pest control schemes across the globe; but little is known about their impacts on free-grazing domestic birds and the quality of meat or eggs produced from such birds. This study assessed the pollution and partitioning of neonicotinoids in serum and eggs of free-grazing ducks from 5 provinces of Thailand and elucidated the associated human health implications. Biological samples (duck serum, egg albumins, and egg yolks) and environmental samples (soil, water, feed) were collected from 9 duck farms in Thailand and subjected to LC/MS/MS analysis. Out of 6 neonicotinoid compounds targeted, five were detected in duck serum. Imidacloprid had the greatest median concentration of 1.4 ng/mL and the highest detection frequency (df) of 85.8 % in the ducks' serum, followed by acetamiprid (median concentration = 0.4 ng/mL; df = 2.8 %), clothianidin (median concentration = 0.2 ng/mL; df = 9.4 %) or thiamethoxam (median concentration = 0.2 ng/mL; df = 7.5 %) and dinotefuran (only one sample was contaminated with 6.3 ng/mL of dinotefuran). The neonicotinoids were similarly detected in soil, water, and feed samples obtained from the duck farms, suggesting that the ducks were exposed to the insecticides from the nearby agricultural fields. The neonicotinoid compounds selectively accumulated in the albumin of duck eggs compared to yolk. The median concentration ratios of albumin to yolk obtained for imidacloprid, dinotefuran, thiamethoxam, clothianidin, and acetamiprid were 694, 463, 458, 382, and 263, respectively. However, upon human health risk analysis, levels of neonicotinoids detected in duck eggs were not found to present any appreciable risks to duck egg consumers.

Expanded characterization and localization of male seminal fluid proteins within the female reproductive tract of the dengue vector mosquito Aedes aegypti

Aedes aegypti mosquitoes transmit numerous viruses that impact human health. Contemporary biological control programs aim to reduce Aedes fertility despite our limited understanding of interactions between the sexes required for reproduction. During mating, males transfer seminal fluid proteins (SFPs) to females which alter their post-mating behavior, physiology and gene regulation, but the contribution of individual SFPs to fertility remains uncharacterized. In Drosophila, a small subset of SFPs localize to the sperm storage organs and oviducts or enter the hemolymph which suggests their participation in specific post-mating processes. We used mass spectrometry-based proteomics in conjunction with whole animal heavy labelling to expand the characterization of the Ae. aegypti ejaculate and identify SFPs that leave the site of insemination and localize to other female tissues. We identified 1031 ejaculate proteins, including a suite of novel SFPs. The expanded ejaculate proteome shows low conservation amongst SFPs when compared to insect model Drosophila, consistent with rapid evolutionary turnover at the genetic and proteomic levels. Further, we identify 25 SFPs that localize to the spermathecae, oviducts, and/or enter the hemolymph. This study expands our knowledge of the Ae. aegypti seminal fluid proteome and identifies candidate SFPs that may have tissue-specific, postcopulatory roles which support fertility. SIGNIFICANCE: Male-derived seminal fluid proteins (SFPs), transferred to females along with sperm during mating, are essential for the fertility of a mating pair. SFPs in aggregate induce several physiological and behavioral changes in mated females. Studies in the insect model Drosophila have shown that individual SFPs often participate in specific post-mating processes. In the dengue vector mosquito Aedes aegypti, 177 high confidence SFPs have been identified, but the contribution of individual SFPs in female fertility has yet not been characterized. In Drosophila, a small subset of SFPs leave the site of insemination and localize to the oviduct and sperm storage organs of the female reproductive tract or are transported to the female hemolymph, with patterns of SFP localization suggesting participation in a specific post-mating process. We used MS/MS proteomic characterization coupled with whole animal heavy labeling to expand characterization of the Ae. aegypti ejaculate proteome, increasing the number of known ejaculate proteins to 1378, including identification of 40 novel SFPs. Further, we identified 25 SFPs that leave the site of insemination and localize to the oviducts and/or spermathecae or enter the hemolymph, which can now be assessed for potential tissue-specific functions in female fertility.

Rational application of QoIs fungicides to achieve a rice-fungi-fish interaction balance within paddy ecosystems

In the realm of agricultural chemical research, elucidating the mechanisms underlying the selectivity of quinone outside inhibitors (QoIs) is crucial for guiding the development of novel pesticides. In this study, differences in the selectivity and toxicity of 12 QoIs were evaluated using three organisms (Magnaporthe oryzae, zebrafish, and rice) present in paddy fields. The interplay between the specific mechanisms of QoIs selectivity among different organisms and the variations in individual toxicity remains unclear. Therefore, the distinct levels of enrichment behavior, cell toxicity, and target enzyme toxicity of 12 QoIs across three organisms were investigated in this research. Additionally, an attempt was made to analyze the correlation between structural parameters and the degree of toxicity at the tissue, cellular, and target levels to establish the regulatory direction of QoIs activity and toxicity. The results revealed that cytotoxicity and target enzyme toxicity played significant roles in the toxicity observed in individuals, specifically in fish and fungus, respectively. The results of this study revealed a significant negative correlation between the bioconcentration factor (BCF) in biological tissues and fish toxicity (LC50) (P < 0.05), but no significant correlation between BCF of fungus and fungitoxicity (EC50) was detected (P > 0.05). Reducing the Log P (octanol-water partition coefficient) and further changing tissue enrichment could balance the toxicity and activity of QoIs in organisms. On the basis of the aforementioned findings, introducing hydrophilic groups into the structure of pyraclostrobin with lower Log P values was an effective strategy for designing new QoI structures. These modified structures demonstrated reduced toxicity to fish and promising fungitoxicity against rice blast fungus compared with pyraclostrobin. This study provides valuable insights for regulatory measures in the design and development of effective and safe new QoIs in paddy fields, further reducing adverse impacts on paddy fields and aquatic ecosystems.

NF-κB-mediated developmental delay extends lifespan in Drosophila

Developmental time (or time to maturity) strongly correlates with an animal's maximum lifespan, with late-maturing individuals often living longer. However, the genetic mechanisms underlying this phenomenon remain largely unknown. This may be because most previously identified longevity genes regulate growth rate rather than developmental time. To address this gap, we genetically manipulated prothoracicotropic hormone (PTTH), the primary regulator of developmental timing in Drosophila, to explore the genetic link between developmental time and longevity. Loss of PTTH delays developmental timing without altering the growth rate. Intriguingly, PTTH mutants exhibit extended lifespan despite their larger body size. This lifespan extension depends on ecdysone signaling, as feeding 20-hydroxyecdysone to PTTH mutants reverses the effect. Mechanistically, loss of PTTH blunts age-dependent chronic inflammation, specifically in fly hepatocytes (oenocytes). Developmental transcriptomics reveal that NF-κB signaling activates during larva-to-adult transition, with PTTH inducing this signaling via ecdysone. Notably, time-restricted and oenocyte-specific silencing of Relish (an NF-κB homolog) at early 3rd instar larval stages significantly prolongs adult lifespan while delaying pupariation. Our study establishes an aging model that uncouples developmental time from growth rate, highlighting NF-κB signaling as a key developmental program in linking developmental time to adult lifespan.

Distinguishing species boundaries from geographic variation

In an era of unprecedented biodiversity loss, the need for standardized practices to describe biological variation is becoming increasingly important. As with all scientific endeavors, species delimitation needs to be explicit, testable, and refutable. A fundamental task in species delimitation is distinguishing within-species variation from among-species variation. Many species that are distributed across large geographic areas exhibit levels of genetic variation that are as great or greater than those that exist between well-defined sympatric species. Here, we provide a workflow to distinguish between intra- and interspecific genetic variation and apply the workflow to a taxonomically problematic group of frogs (the Rana pipiens complex, or leopard frogs) that are widely distributed across Mexico and Central America. Our workflow makes use of recent advancements that pair genome-scale datasets with model-based species delimitation methods, while emphasizing the need for positive evidence of reproductive isolation to confirm the validity of geographically contiguous species boundaries. We find that intraspecific geographic variation in widespread leopard frog species has resulted in considerable taxonomic inflation of species. Ten currently recognized species are not supported in our analyses, and we here synonymize them with previously named taxa. Furthermore, we find positive evidence for the presence of three undescribed species. In addition to proposing these taxonomic changes, we provide descriptions of the data or analyses that would be needed to refute and overturn our recommendations. We recommend that all species delimitation studies (especially of geographically variable groups) clarify what new evidence would be sufficient to change the taxonomic recommendations.

Dynamic interplay between niche variation and flight adaptability drove a hundred million years' dispersion in iconic lacewings

The form and change of animal biogeography reflects the long-term interplay between organisms and their environment, involving physiological limitation, dispersal capability, and adaptive evolution versus plate tectonics, global climatic shifts, and changing landscapes. This is especially manifest for lineages with extended geological histories, which, therefore, evokes questions as to the associated processes producing such patterns. Insects, as the earliest flying animals, have exceptional abilities for expanding their range and habitats and to avoid detrimental conditions. They are ideal for exploring historical biogeography augmented via adaptation. Here, we employ beaded lacewings as a model to explore such patterns and likely processes, particularly given that they differ notably from the commonly observed pattern of a latitudinal diversity gradient. Furthermore, owing to their good fossil record it can be observed that their distributions varied remarkably through time. Ecological niche modeling and evaluation demonstrate their niche variation and niche breadth expansion intermittently accompanying global climate change. However, different niche relevant variables changed under patterns of either phylogenetic conservatism or evolutionary lability. By assessing wing morphological disparity and modeling flight aerodynamics, we uncovered a continuous improvement of flight efficiency through beaded-lacewing history as well as a Paleogene divergence in strategy, which reveals a long-term associated path with the niche variation. Our results unveil the adaptive evolution and dispersal history of beaded lacewings through 170 My, achieved by dynamic strategies in niche shift and flight adaptation as responses to a changing planet.

Ethylene signaling is essential for mycorrhiza-induced resistance against chewing herbivores in tomato

Arbuscular mycorrhizal (AM) symbiosis can prime plant defenses, leading to mycorrhiza-induced resistance (MIR) against different attackers, including insect herbivores. Still, our knowledge of the complex molecular regulation leading to MIR is very limited. Here, we showed that the AM fungus Funneliformis mosseae protects tomato plants against two different chewing herbivores, Spodoptera exigua and Manduca sexta. We explored the underlying molecular mechanism through genome-wide transcriptional profiling, bioinformatics network analyses, and functional bioassays. Herbivore-triggered jasmonate (JA)-regulated defenses were primed in leaves of mycorrhizal plants. Likewise, ethylene (ET) biosynthesis and signaling were also higher in leaves of mycorrhizal plants both before and after herbivory. We hypothesized that fine-tuned ET signaling is required for the primed defense response leading to MIR. ET is a complex regulator of plant responses to stress and is generally considered a negative regulator of plant defenses against herbivory. However, ET-deficient or insensitive lines did not show AM-primed JA biosynthesis or defense response, and were unable to develop MIR against any of the herbivores. Thus, we demonstrate that hormone crosstalk is central to the priming of plant immunity by beneficial microbes, with ET fine-tuning being essential for the primed JA biosynthesis and boosted defenses leading to MIR in tomato.

Timing since deforestation for pastures implementation in the western Amazon: Impacts on stream water biogeochemistry

Water quality degradation is a global concern and land use changes is one of the main causes of water pollution globally. In the Brazilian Amazon, large-scale deforestation is mostly associated to pasturelands, with strong implications for soils and stream waters biogeochemistry and resulting in environmental degradation. Studies addressing soil biogeochemistry in Amazonian pastures of different ages documented a consistent pattern of elements peaking on the first years after deforestation, followed by a continuous decrease until reach depletion in older, degraded pastures. The same pattern is expected on the adjacent stream water biogeochemistry due to the land-water connection; however, this issue has not being explored. We assessed how timing since deforestation impacts water biogeochemistry in streams of Rondônia State, Brazil, a region that showed a relatively fast colonization process associated to large-scale deforestation for pasture implementation since 1970. Mapping deforestation from 1984 to 2011 and collecting water samples in 2012 for 41 headwater catchments, we (i) compared water biogeochemistry among streams draining undisturbed catchments with primary forests (PRI) and streams draining pasture catchments deforested mostly in a recent (NEW) and in a distant past (OLD); and (ii) related water biogeochemistry with land use intensity (pasture permanency along years), also considering the effect of covariates (soils, forest cover, and catchment area) in our analysis. Our results indicate that pasture implementation altered the concentrations of ions and nutrients in the stream ecosystem, with distinct water quality impacts between newer and older pastures. In general, the longer the area stayed under pasture use, the larger were the alterations in the water biogeochemistry (lower NO3-, DOC, and DOX and higher Ca2+, Mg2+, DIC and COND). Pasture degradation is a widespread process in the Amazon and it is strongly associated to increasing deforestation. Thus, pasture reclamation and intensification is urgently necessary to achieve the long-term productivity and sustainability of Amazonian pasturelands, avoiding new deforestation and environmental degradation. Adopting Best Management Practices (riparian forested buffers) is another action to protect water resources in the region.

Sex-Biased Gene Expression of RNAi Pathway Components in the Sea Lice Caligus rogercresseyi

RNA interference (RNAi) is a conserved mechanism for post-transcriptional gene regulation and a critical process of arthropod immunity. This study investigates RNAi-associated genes in Caligus rogercresseyi, an ectoparasitic sea louse that poses significant challenges to salmon aquaculture. In that regard, 16 RNAi-associated genes were identified by in silico analysis, including Cr-AGO1, Cr-CNOT1, Cr-DCR, Cr-SND1, and Cr-XRN1. Phylogenetic analysis demonstrated clustering with homologous sequences from other arthropods, particularly the ectoparasitic copepod Lepeophtheirus salmonis. RNA-Seq analyses revealed developmentally regulated expression patterns, with RNAi-associated genes clustered into four distinct expression profiles. Quantitative PCR (qPCR) validation confirmed significant male-biased expression for several key genes, including Cr-AGO1 (109-fold increase), Cr-DCR (22-fold), Cr-XRN1 (22-fold), Cr-SND1 (fourfold), and Cr-CNOT1 (threefold), suggesting potential roles in male reproductive processes such as spermatogenesis. Cr-DDX6, Cr-Drosha, and Cr-XPO5, potentially involved in oocyte development and RNA transport, exhibited female-biased expression. These results provide new insights into RNAi-associated gene expression in C. rogercresseyi, uncovering significant developmental and sex-biased expression patterns. Characterizing these critical genes establishes a foundation for exploring control strategies based on the RNAi process, targeting sex-biased and developmentally essential genes. Such treatments could reduce reproductive success in sea lice while minimizing environmental impact, offering a sustainable alternative for managing caligidosis in aquaculture.

Two independent regulatory mechanisms synergistically contribute to P450-mediated insecticide resistance in a lepidopteran pest, Spodoptera exigua

BACKGROUND

Cytochrome P450 enzymes play a pivotal role in the detoxification of plant allelochemicals and insecticides. Overexpression of P450 genes has been proven to be involved in insecticide resistance in insects. However, the molecular mechanisms underlying the regulation of P450 genes in insects are poorly understood.

RESULTS

Here, we determine that upregulation of CYP321B1 confers resistance to organophosphate (chlorpyrifos) and pyrethroid (cypermethrin and deltamethrin) insecticides in the resistant Spodoptera exigua strain. Enhanced expression of transcription factors CncC/Maf contributes to the increase in the expression of CYP321B1 in the resistant strain. Reporter gene assays and site-directed mutagenesis analyses confirm that a specific binding site is crucial for binding CncC/Maf to activate the expression of CYP321B1. In addition, creation of a new binding site resulting from the cis-mutations in the promoter region of CYP321B1 in the resistant strain facilitates the binding of the POU/homeodomain transcription factor Nubbin, and further enhances the expression of this P450 gene. Furthermore, we authenticate that changes in both trans- and cis-regulatory elements in the promoter region of CYP321B1 act in combination to modulate the promoter activity in a synergistic manner.

CONCLUSIONS

Collectively, these results demonstrate that two distinct but synergistic mechanisms coordinately result in the overexpression of CYP321B1 involved in insecticide resistance in an agriculturally important insect pest, S. exigua. The information on mechanisms of metabolic resistance could help to understand the development of resistance to insecticides by other pests and contribute to designing effective integrated pest management strategies for the pest control.

Chemical Recognition Cues in Ant-Aphid Mutualism: Differentiating, Sharing, and Modifying Cuticular Components

Aphid-tending ants form mutualistic associations with aphids. During their interactions, aphids and ants use both tactile stimuli and chemical cues to communicate. Recent studies suggest that ants modify the cuticular hydrocarbons of mutualistic aphids they attend, but it is unclear which compounds are implicated in recognition. Thus, we investigated the chemical basis for the discrimination between attended and unattended aphids, Aphis gossypii Glover (Hemiptera: Aphididae), by the ant Tapinoma ibericum (Santschi, 1925) including cuticular hydrocarbons (CHCs and non-CHCs) compounds in the analysis. Chemical profiles of 14 colonies of A. gossypii attended by ants for three days were significantly different from those of unattended aphids. These results show that contact with T. ibericum rapidly induces modification of the cuticular profiles of the aphids on which they feed. Moreover, the compounds of unattended aphid A. gossypii also change over time but differ from those of attended aphids. The main compound of the ant cuticle (3,15-di-MeC27), which is highly abundant in attended aphids, was identified as a possible recognition marker, but without forgetting other identified compounds that may also play a predominant role in the ant-aphid mutualistic interactions. These promising compounds represent opportunities for pest control strategies using chemical manipulations.

What maintains variation in flower accessibility to pollinators in plant communities? A simulation study

BACKGROUND

Flowers in natural plant communities come in many shapes. Flowers with restrictive morphologies are considered complex, because only a subset of pollinators are able to learn how to access their nectar and pollen. Other flowers are easily accessible to diverse pollinating insects, and are regarded as simple. How and why do the two types of flowers coexist in natural plant communities? We developed a spatially explicit evolutionary simulation framework to explore this question. We modeled the dynamics of two types of flowers ('complex' and 'simple') that differ in accessibility to their simulated pollinators and in food rewards. The flowers are visited by a population of pollinators, which initially possess heritable variation in their ability to learn to forage on the complex flowers. We manipulated the pollinators' flying distances and the flowers' overall density, spatial distribution, and starting proportion of simple flowers. We recorded the resulting dynamics of the two flower types in the community, and of the pollinators' learning rates, over 100 generations.

RESULTS

Complex and simple flowers coexisted under all simulated conditions. The steady-state community always contained more simple flowers than complex ones. Complex flowers attained higher frequencies when flowers were highly aggregated than when flower aggregation was low. Long-distance fliers evolved higher learning abilities than short-distance fliers. Pollinator learning abilities, in turn, were positively correlated with the frequency of complex flowers.

CONCLUSIONS

Frequencies of complex flowers vary among natural plant communities. Our model predicts that this variation is shaped by the plants' spatial distribution as well as by the cognitive abilities of their pollinators. The model generates novel and testable hypotheses for understanding how diversity in flower shapes is maintained in natural plant communities.

Ectoparasites enhance survival by suppressing host exploration and limiting dispersal

Parasites enhance their fitness by manipulating host dispersal. However, the strategies used by ectoparasites to influence host movement and the underlying mechanisms remain poorly understood. Here, we show that ectoparasites alter metabolic activity in specific brain regions of mice, with evidence pointing to a potential role for microglial activation in the prefrontal cortex. This activation appears to contribute to synaptic changes and altered neuronal differentiation, particularly in GABAergic neurons. Consequently, exploratory behavior decreases-an effect likely mediated through the skin-brain axis. In both indoor and field experiments with striped hamsters, ectoparasites reduce host exploration and modify their dispersal patterns. This behavioral shift ultimately restricts the host's distribution, enabling parasites to avoid environmental pressures. Our findings reveal that ectoparasites limit host dispersal to improve their own fitness, offering key insights for parasite control strategies that promote health and preserve ecological stability within the One Health framework.

Auxin-salicylic acid seesaw regulates the age-dependent balance between plant growth and herbivore defense

According to the plant vigor hypothesis, younger, more vigorous plants tend to be more susceptible to herbivores compared to older, mature plants, yet the molecular mechanisms underlying this dynamic remain elusive. Here, we uncover a hormonal cross-talk framework that orchestrates the age-related balance between plant growth and herbivore defense. We demonstrate that the accumulation of salicylic acid (SA), synthesized by Nicotiana benthamiana phenylalanine ammonia-lyase 6 (NbPAL6), dictates insect resistance in adult plants. NbPAL6 expression is driven by the key transcription factor, NbMYB42, which is regulated by two interacting auxin response factors, NbARF18La/b. In juvenile plants, higher auxin levels activate NbmiR160c, a microRNA that simultaneously silences NbARF18La/b, subsequently reducing NbMYB42 expression, lowering SA accumulation, and thus weakening herbivore defense. Excessive SA in juvenile plants enhances defense but antagonizes auxin signaling, impairing early growth. Our findings suggest a seesaw-like model that balances growth and defense depending on the plant's developmental stage.

Functional characterization of eicosanoid signaling in Drosophila development

20-carbon fatty acid-derived eicosanoids are versatile signaling oxylipins in mammals. In particular, a group of eicosanoids termed prostanoids are involved in multiple physiological processes, such as reproduction and immune responses. Although some eicosanoids such as prostaglandin E2 (PGE2) have been detected in some insect species, molecular mechanisms of eicosanoid synthesis and signal transduction in insects have not been thoroughly investigated. Our phylogenetic analysis indicated that, in clear contrast to the presence of numerous receptors for oxylipins and other lipid mediators in humans, the Drosophila genome only possesses a single ortholog of such receptors, which is homologous to human prostanoid receptors. This G protein-coupled receptor, named Prostaglandin Receptor or PGR, is activated by PGE2 and its isomer PGD2 in Drosophila S2 cells. PGR mutant flies die as pharate adults with insufficient tracheal development, which can be rescued by supplying high oxygen. Consistent with this, through a comprehensive mutagenesis approach, we identified a Drosophila PGE synthase whose mutants show similar pharate adult lethality with hypoxia responses. Drosophila thus has a highly simplified eicosanoid signaling pathway as compared to humans, and it may provide an ideal model system for investigating evolutionarily conserved aspects of eicosanoid signaling.

Epidemiology of Intracellular Bacterial Pathogens Rickettsia Spp., Borrelia Spp., Coxiella Spp., and Bartonella Spp. in West Africa from 2000 to 2023: A Systematic Review

Background: Intracellular bacteria such as Rickettsia spp., Borrelia spp., Coxiella spp., and Bartonella spp. cause febrile illnesses similar to malaria and arboviruses, leading to under-reporting in sub-Saharan Africa. Methods: Following Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines, we included studies on these bacteria in humans, animals, and vectors in West Africa (2000-2023). Case reports, editorials, studies on other pathogens, and coinfections were excluded. Data was retrieved from African Journals Online, Google Scholar, and PubMed (last search: December 31, 2023). The risk of bias was assessed using an adapted Cochrane RoB 2.0 tool. Data were analyzed using Excel 2016 and QGIS. A random-effects model estimated prevalence, with subgroup analysis based on country, detection method, period, and host type. Heterogeneity was measured via the I2 index (>50% indicating moderate heterogeneity). Publication bias was assessed by stratifying studies by risk of bias. Results: Out of 27 articles included, 10 covered studies on Rickettsia spp., 5 Borrelia spp., 6 Coxiella spp., 3 Bartonella spp., and 3 both Rickettsia spp. and Coxiella spp. Among them, 10 studies focused on vectors, 5 on animals, 5 on humans, and 7 on One Health. The prevalence of Rickettsia spp. was the highest in humans, 19.46%, 95% confidence interval: [19.42-19.50]. Bartonella spp. had the highest prevalence in animals, 82.57%, 95% CI: [82.46-82.69], and vectors 37.62%, 95% CI: [37.53-37.71]. Prevalence increased significantly post 2010 (81.4%). PCR-based detection showed a higher prevalence (63%). In the risk-of-bias analysis, the quality of the studies, which were included, did not affect the results and overall validity of findings. Conclusion: Intracellular bacteria spread widely among humans, animals, and vectors. One Health approach is essential for managing zoonotic bacterial diseases in Africa. Variation in prevalence underlines the need for methodological standardization and future research should focus on harmonizing methods by integrating molecular methods.

Identification of MsCYP79 and MsCYP83 gene families and its response to mechanical damage in Medicago sativa L

Glucosinolate are one of the vital secondary metabolites in alfalfa (Medicago sativa L.), and primarily present as β-D-glucosinolate derivatives, improving the resistance in response to biotic and abiotic stresses of alfalfa. CYP79 (Cytochrome P450 monooxygenases) and CYP83 gene families play an important role in the core structure biosynthesis of glucosinolate. Nevertheless, a comprehensive exploration of CYP79 and CYP83 family members in alfalfa has thus far not been study. The types of glucosinolate in alfalfa were qualitative and quantitative analysis by UPLC-MS/MS. Then, we identified MsCYP79 and MsCYP83 gene families in alfalfa, and scrutinized the physicochemical attributes, gene architecture, collinearity, evolutionary trajectories, as well as expression patterns under mechanical damage. The findings revealed the glucosinolate metabolites of alfalfa divided into three classes, including 27 aliphatic glucosinolates, 9 aromatic glucosinolates, and 5 indole glucosinolates. In addition, 59 MsCYP79 family members and 56 MsCYP83 family members were identified in alfalfa, which were classified into eight main groups based on phylogenetic analysis. MsCYP79 and MsCYP83 were distributed unevenly on 26 chromosomes and had 2-6 exons. Then, employing MEME software unveiled 15 conserved motifs within the protein structures of MsCYP79 and MsCYP83. Real-time quantitative PCR was used to detect the expression level of MsCYP79 and MsCYP83 genes and demonstrated that the selected genes in alfalfa were tissue-specific and had different expression patterns in response to mechanical damage. This investigation laid a robust groundwork for substantiating the functions of MsCYP79 and MsCYP83 and facilitating the cultivation of alfalfa varieties enriched in glucosinolate content.

Mycorrhizal fungus colonization on maize seedlings diminishes oviposition of fall armyworm females and affect larval performance

Arbuscular mycorrhizal fungi are key components of the soil microbiota and are characterized by their symbiosis with terrestrial plants. In addition to providing nutrients to plants during symbiosis, arbuscular mycorrhizal fungi can enhance plant defenses against herbivorous insects and pathogens, including induced systemic resistance. Previous studies have demonstrated that Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) larvae perform better in maize plants colonized by arbuscular mycorrhizal fungi, which generally exhibit greater growth and higher nitrogen and phosphorus contents. However, these studies were limited to a small number of maize varieties. Additionally, prior research has not considered the host preference of S. frugiperda females for noncolonized versus arbuscular mycorrhizal fungi-colonized maize plants, although female choice can significantly influence progeny performance. In this study, we evaluated the effects of Rhizophagus irregularis (Blaszk, Wubet, Renker, & Buscot) C. Walker & A. Schüßler (Glomerales: Glomeraceae) inoculation on 4 maize inbred lines (CML 124, CML 343, CML 122, and CML 126) susceptible to S. frugiperda on female oviposition preference and larval performance of S. frugiperda. Overall, females preferred ovipositing on uncolonized seedlings to arbuscular mycorrhizal fungi-colonized seedlings, independent of the inbred lines. Larval performance was affected by inbred lines and arbuscular mycorrhizal fungi colonization. Larvae feeding on noncolonized maize seedlings exhibited significantly higher weights than those feeding on arbuscular mycorrhizal fungi-colonized seedlings. Among the inbred lines, larvae fed CML 122 performed better than those fed CML 126 and CML 343 seedlings. The weight of the larvae fed on CML 124 seedlings was similar to that of the larvae fed on CML 122, CML 126, and CML 343 seedlings.

Mechanisms mediating false codling moth, Thaumatotibia leucotreta (lepidoptera: Tortricidae), mating disruption using point-source pheromone dispensers

BACKGROUND

False codling moth (FCM) is a polyphagous Tortricid moth that is a priority agricultural pest. Mating disruption shows potential as an environmentally friendly and sustainable control option against FCM in stone fruit, table grapes and citrus. How the technique alters the mate-finding ability of FCM and what factors are important to ensure the control success is uncertain. Recent work indicated that Lepidoptera are disrupted either competitively or non-competitively. No studies have yet been conducted on FCM to determine its disruptive mechanism. However, studies conducted on closely related species have proposed and critically evaluated a framework, along with a dichotomous key, for distinguishing between the two mechanisms.

RESULTS

A protocol for identifying the underlying disruption mechanism in other species is provided. Here the dosage-response profile, the optimal dosage and optimal density were calculated from multiple mark-release-recapture (MRR) experiments, using sterile FCM. Stone fruit and table grape blocks were treated with increasing levels of pheromone dispenser densities, which allowed the level of disruption experienced (FCM caught in treated/untreated blocks) to be calculated. While mating disruption proved highly effective in stone fruit and table grapes against FCM, the FCM followed a hybrid disruption profile and were disrupted competitively at low dosages and non-competitively at higher dosages.

CONCLUSION

The shift to non-competitive disruption, which resulted in 99% disruption, was achieved at a dosage of 800 dispensers/ha uniformly distributed and remained effective with as few as 36 pheromone release sites per ha. Mating disruption is, therefore, highly recommended to form part of the current integrated pest management program for FCM. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Life-stage dependent behavior mimics chemosensory repertoire diversity in a belowground, specialist herbivore

Insects rely on the translation of environmental chemical cues into behaviors necessary for survival and reproduction. Specific chemosensory receptors belonging to the odorant and gustatory receptor groups detect odorant and gustatory cues, respectively, making them crucial to these processes. How odorant (OR) and gustatory (GR) receptor expression profiles change in combination with changing life strategies is not well understood. Using genomic and transcriptomic resources, we annotated the OR and GR expression profiles across all life stages of the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, a major pest of corn in the United States and Europe. Genomic analyses identified 193 ORs and 189 GRs, of which 125 and 116 were found to be expressed, respectively, in one or more WCR life stages. WCR larvae are subterranean and feed on roots before emerging as adults aboveground. Expression profile analyses revealed first instar larvae possess a unique OR and GR repertoire distinct from other instars and adults, suggesting a role in host plant finding. Similarly, a subset of ORs and GRs differed in their expression levels between adult male and female antennae. By comparing the phylogenetic relationship of ORs and GRs, we identified several receptors with potentially important roles in WCR foraging and reproductive behavior. Together, this study provides support for future investigations into the ecology and evolution of chemoreception in insects.

Diversity in trap color and height increases species richness of bark and woodboring beetles detected in multiple funnel traps

Early detection of non-native, potentially invasive bark beetles and woodboring beetles (BBWB) (Coleoptera: Buprestidae, Cerambycidae, Disteniidae; Curculionidae: Scolytinae) inadvertently introduced to new habitats via global trade is a critical issue for regulatory agencies in numerous countries. We conducted trapping experiments to evaluate the effects of trap color (black vs. green vs. purple) and trap height (canopy vs. understory) on detection of BBWB in Canada, Poland, USA, and China, using Fluon-treated 12-unit multiple-funnel traps. Each trap was baited with the same pheromone and ethanol lures known to attract several species of BBWB. We predicted BBWB species composition would differ between vertical strata and among trap colors, and that the number of BBWB species detected would increase with greater diversity of trapping methods, i.e., by using more than one color of trap and by placing traps in both the canopy and understory. Our prediction was partially supported, i.e., placing one color of trap in the understory and a different colored trap in the canopy detected more species than did a single trap color placed in either the understory or canopy. However, the combinations of trap height and colors that detected the most species varied among sites. The community of BBWB species captured in traps was significantly affected by trap height and trap color at all sites, with the strongest patterns in the data from Poland and the USA. Black and purple traps caught similar communities of BBWB species in the canopy and understory, but green traps caught a different species assemblage in the canopy in Poland and the USA. Effects of trap height and color on species richness were consistent across all four sites within the subfamilies Agrilinae (more species captured in green canopy traps than any other trap height-color combination), Chrysochroinae (more species captured in purple canopy traps than any trap height-color combination) and Scolytinae (more species captured in the understory than the canopy and no effect of trap color), but varied significantly among sites within Cerambycidae subfamilies. None of the species accumulation curves reached an asymptote for any trap color-height combination at any site, indicating that 8-9 traps per site were not sufficient to detect all BBWB species present. Thus, increasing the number of traps deployed per site will increase the BBWB species richness captured and the chances of detecting non-native species that may be present.

Chitosan nanoparticle-mediated delivery of dsRNA for enhancing RNAi efficiency in Locusta migratoria

BACKGROUND

RNA interference (RNAi) targeting the key genes involved in insect growth and development has been demonstrated as pollution-free green pest management strategies. Double-stranded RNA (dsRNA)-based biopesticides offer species-specific pest control and degrade rapidly in the environment, making them a safer alternative to conventional chemical pesticides. However, efficient delivery of dsRNA is a significant challenge in the application of RNAi technology for pest management.

RESULTS

Chitosan, a natural biopolymer, was selected to generate nanoparticles with dsRNA of LmCht10, which is responsible for chitin degradation, for delivery of dsLmCht10 in Locusta migratoria. Compared with the naked dsLmCht10, application of chitosan/dsLmCht10 nanoparticles enhanced the stability of dsRNA in the locust gut fluid in vitro. Feeding the locusts with chitosan/dsLmCht10 nanoparticles resulted in a 67% decrease of LmCht10 transcripts and a 2-fold increase in locust mortality. Injection of chitosan/dsLmCht10 into the locust body cavity substantially improved RNAi efficiency against LmCht10 by 96.6% associated with a 2-fold increase in locust mortality. In addition, the absorption of chitosan/dsLmCht10 nanoparticles by locust epidermal cells increased significantly and continuously by 7.3 to 8.3 times.

CONCLUSION

This study has demonstrated that chitosan-based dsRNA nanomaterials can significantly improve the stability of dsRNA in the midgut fluid, enhance RNAi efficiency, and increase insect mortality. Moreover, chitosan-based dsRNA delivery enhances silencing efficiency by increasing the uptake of dsRNA in the epidermal cells. Our results suggest that the use of chitosan nanomaterial for dsRNA delivery is a feasible strategy for advancing the application of RNAi technology in pest management. © 2025 Society of Chemical Industry.

Niemann-Pick C2 proteins play crucial role in perception of plant volatiles in Tetranychus cinnabarinus

BACKGROUND

Herbivorous mites perceive odorants through olfactory mechanisms, though the molecular basis of olfaction in these species remains poorly understood. Recent studies have identified Niemann-Pick C2 (NPC2) proteins as odorant carriers in the peripheral olfactory systems of insects. Multiple NPC2 genes have been discovered in spider mite genomes, yet their specific roles in olfactory function have not been fully explored.

RESULTS

Behavioral assays showed that 8 of the 12 tested plant volatiles elicited either repellent or attractive responses in Tetranychus cinnabarinus. Two NPC2 genes were identified as responsive to odorant stimulation. Recombinant NPC2 proteins were produced, and microscale thermophoresis (MST) assays revealed specific binding: TcinNPC2-2 bound to geranylacetone [dissociation constant (Kd) = 3.32 μm], and TcinNPC2-3 bound to farnesol (Kd = 9.55 μm). Knockdown of NPC2 genes via RNA interference abolished mite responses to these odorants in behavioral assays.

CONCLUSIONS

Mite olfactory responses to a number of odorants were widely documented. NPC2-2 and NPC2-3 proteins play critical roles in the olfactory detection of geranylacetone and farnesol, respectively. This study enhances our understanding of the peripheral olfactory processes in herbivorous mites, offering insights for the development of behavior-targeting agents for mite control. © 2025 Society of Chemical Industry.

Epizootic hemorrhagic disease virus oral infection affects midge reproduction and is vertically transmitted to offspring in Culicoides sonorensis

Epizootic hemorrhagic disease virus (EHDV: Reoviridae: Orbivirus) is a Culicoides-borne pathogen that affects a variety of ruminants, causing significant economic losses and/or ecological impacts in animal agriculture/wildlife populations worldwide. In this study, we examined the effect of EHDV serotype-2 oral infection on the survival and reproduction of Culicoides sonorensis Wirth and Jones (a confirmed vector of EHDV in North America), and the potential vertical transmission of EHDV-2 (from infected female to its offspring) in this midge species. Culicoides sonorensis females were fed on defibrinated bovine blood mixed with EHDV-2 (5.5 log10 PFU/ml) or without EHDV-2 (control). Adult survival/longevity, oviposition rates, number of eggs deposited, egg hatch rates (fertility), larval survival, larval stage duration, eclosion rates, and sex-ratios of the progeny were recorded and compared between the two groups. In addition, the progeny (eggs and F1 generation adults) of EHDV-2 fed females were processed for viral detection through RT-qPCR and plaque assays. Survival/longevity of the blood-fed adults, oviposition rates, number of eggs deposited, larval stage duration, eclosion rates, and sex-ratios were not significantly different between the two groups. However, egg hatch rates were significantly lower in the EHDV-2 fed group (35.8 ± 5.2%) than the control group (74.5 ± 6.8%), but larval survival rates were higher in the EHDV-2 fed group (59.8 ± 4.9%) compared to the control group (34.1 ± 6.5%). EHDV-2 (Ct < 35) was detected in the eggs (3.4%, 1/29 females tested, Ct = 22.1 [4.9 log10 PFUe/ml]) and F1 adult progeny (1.7%, 1/58 adults tested, Ct = 23.5 [4.5 log10 PFUe/ml]) of the orally exposed females through RT-qPCR as well as through plaque assays. Our findings suggest that EHDV-2 infection has no major impact on C. sonorensis survival/longevity or oviposition but has a significant negative effect on midge fecundity/fertility. Our study also provides evidence for the vertical transmission of EHDV-2 from an infected adult female to its offspring in C. sonorensis. However, salivary transmission of EHDV-2 from the vertically infected progeny and its significance in the epidemiology of hemorrhagic disease are currently unknown and remain to be examined in further studies. Overall, these findings collectively indicate that Orbivirus infection can negatively affect vector reproduction, and that vertical transmission is a probable mechanism of overwintering of EHDV in North America.

RNAi-mediated knockdown of fruitless in Plutella xylostella (Lepidoptera: Plutellidae) disrupts female sex pheromone biosynthesis and male courtship behavior

Strong fecundity is an important reason why the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), has become one of the most serious pests of cruciferous vegetables worldwide. Disrupting with courtship and mating behaviors has emerged as an important strategy for insect management. The fruitless (fru) gene encodes a transcription factor that contains a BTB (Broad-Complex, Tramtrack and Bric a brac) and a zinc finger pair related to the C2H2 class. It plays a crucial role in regulating insect courtship behavior. In this study, the fru gene of P. xylostella (Pxfru) was cloned, revealing 7 alternative splicing forms (Pxfru-1 to Pxfru-7). Pxfru-1 to Pxfru-3 were non-sex-specific transcripts, while the remaining forms were male-specific. Subcellular localization experiments demonstrated that the transcripts encoding proteins containing BTB and zinc finger domains (Pxfru-1 to Pxfru-3) localized to the cell nucleus, whereas Pxfru-4 and Pxfru-5, which contain only one BTB domain, were localized in the nucleus and cytoplasm, respectively. Knockdown the expression of fru in male moths delayed occurrence of mating and reduced their preference to female sex pheromones. Meanwhile, suppression of fru expression in female P. xylostella decreased their attractiveness to males. The results of GC-MS and Y-tube olfaction experiments indicated that this change may be attributed to alterations in the proportion of sex pheromones. This study represents the first report of the fru gene influencing pheromone ratios in female insects, and provides a new perspective for understanding the function of fru in the courtship behavior of non-model insects.

3D is not just a tool - a study of the anal capsule in Craterostigmus tasmanianus Pocock (1902) (Chilopoda, Arthropoda)

Craterostigmus tasmanianus Pocock, 1902, is a chilopod distinguished, among other features, by a unique structure known as the anal capsule. Morphological questions regarding the anal capsule pertain to the homology of its functional components when compared to other chilopods, as well as the morpho-functional mechanisms involved in its opening and closing. Additionally, there has been ongoing debate about the precise location of the anus on the anal capsule. Some studies have suggested that the anus is located at the posterior end of the capsule, while others have proposed a position in the middle of the ventral side of the capsule. To address these questions, μCT and cLSM scans were conducted on the anal capsule of C. tasmanianus and the posterior segments of Scutigera coleoptrata (Linnaeus, 1758). The resulting data were processed using 3D visualization software. Different muscle groups were identified, and the cuticle was analyzed to determine the presence of resilin, a highly elastic component in arthropod cuticles. Based on the findings, hypotheses were formulated regarding the morpho-functional mechanisms of movement and the homology of the anal capsule structures in C. tasmanianus and S. coleoptrata. The analysis also resolved the question of anus location, confirming that it is situated at the posterior end of the anal capsule.

Battle between Gut Bacteria, Immune System, and Cry1Ac Toxin in Plutella xylostella

Research on Bacillus thuringiensis (Bt)-pest interactions has prioritized Cry toxin receptors, with limited attention to gut bacteria's role in modulating Bt sensitivity. This study identified two Enterobacter strains in Plutella xylostella with opposing effects on Cry1Ac susceptibility. Enterobacter hormaechei (PxG15) degraded Cry1Ac protoxin and activated the proPO-AS and JNK pathway, which reduced Cry1Ac's damage to the midgut while limiting the invasion of gut bacteria into the hemolymph. Although Enterobacter asburiae (PxG1) rapidly activated the proPO-AS, the JNK pathway was activated in a much slower and weaker mode when compared to PxG15, which attenuated the repairing efficiency of the midgut under the treatment of Cry1Ac, leading to death resulting from sepsis from the quick invasion of gut bacteria into the hemolymph. This study illustrates the intricate interrelationships among Cry1Ac, the pest's midgut bacteria, and its immune system, offering novel insights into how gut bacteria shape pest survival following Cry1Ac exposure.

BdorOBP32 Perceiving β-Caryophyllene: A Molecular Target for Female Attractant Development in Bactrocera dorsalis

Bactrocera dorsalis is a destructive agricultural pest that attacks over 600 plant species. β-Caryophyllene is considered a potential compound for developing novel female attractants due to its attraction to B. dorsalis females. However, the unknown perception mechanism of β-caryophyllene has been the bottleneck of this process. Odorant binding proteins (OBPs) function to bind odorants and transport them to olfactory receptors. Here, behavioral assays revealed that β-caryophyllene strongly attracted mated, instead of virgin females. RT-qPCR confirmed BdorOBP32 up-regulation out of five OBPs in mated females compared to virgin females. Microscale thermophoresis (MST) results showed BdorOBP32 bind β-caryophyllene with relatively high affinity. Subsequently, CRISPR/Cas9 knockout of BdorOBP32 reduced electroantennograms responses and behavioral preferences to β-caryophyllene in mutants. Moreover, molecular docking and behavioral analysis identified a novel female attractant (α-angelica lactone) targeting BdorOBP32. These findings highlight BdorOBP32 plays critical roles in β-caryophyllene perception and offer new insights for developing novel olfactory behavior modulators.

Guava root exudate-driven rhizosphere microorganisms changes transmitted to foliar-feeding insects influence their feeding behaviour

The growth of different grafted guava was different as affected by grafting on different rootstock varieties, which also influenced the damage degree of Spodoptera litura larvae. The co-regulation of the pest gut by rhizosphere microorganisms and root exudates may contribute to this differential damage. In this study, the microorganisms of soil, plants, S. litura larvae and root exudates of guava grafted on different rootstock varieties were analysed and compared. The activities of superoxide dismutase, peroxidase and catalase in the midgut of S. litura larvae feeding on heterograft leaves of guava (where rootstock and scion are of the different variety) were significantly higher than those in the midgut of S. litura larvae feeding on homograft leaves of guava (where rootstock and scion are of the same variety), and glutathione s-transferase activity showed an opposite result. Enterococcus spp. and Escherichia spp. were the two bacterial genera with the greatest difference in abundance in the midgut of S. litura larvae and exhibited a negative correlation with each other. The root system of guava influenced the root structure, soil nutrients and the population structure and diversity of rhizosphere microorganisms by regulating the type and amount of root exudates. Root exudates also influenced the physiological and biochemical status of S. litura larvae by regulating the rhizosphere microorganisms driving the tritrophic interaction of plant-microbes-insects. Based on our results and the observed differences in pest occurrence among different grafted plants, improving varieties through grafting may become an effective strategy to reduce the impact of insect pests on guava.

Biased tertiary sex ratios enhance the efficacy of sex-ratio distorting genetic techniques to control invasive species

Genetic biocontrol strategies are increasingly being developed and tested for reducing the effects of invasive species, and are highly likely to be an important tool of integrated pest management in the future. Included among such strategies are those that distort the sex ratio of the target species. Models used to forecast the efficacy of such strategies generally assume, implicitly, that the tertiary sex ratio of the target population is 50:50. We present evidence that this assumption is important, and that if the tertiary sex ratio is biased towards females, a sex-distorting construct introduced into the population that produces phenotypic males will become fixed at a level determined by the magnitude of the bias, even after further introductions cease. We show, first using a simple logistic population model, and second using a realistic simulation of an important aquatic invasive species - the sea lampreyPetromyzon marinus- how this effect can greatly increase the effectiveness of a sex-distorting construct at population suppression, but also increase the risk of such strategies due to reduced reversibility. We also present evidence that biased tertiary sex ratios might be present in many invasive species, particularly when their population sizes are low relative to environmental carrying capacity.

Development time integrates temperature and host plant cues for eyespot size in three tropical satyrine butterflies

Many tropical butterflies have distinct wet and dry season adult morphs differing in the size of wing eyespots. Eyespot size is influenced by the environment experienced by developing larvae, and this plasticity is adaptive because the morphs have higher survival in their respective seasons. Higher temperature during the larval phase produces adults with larger eyespots in many species. This reaction norm is adaptive when high temperatures precede the wet season, which is not the case in all regions. Therefore, butterflies may rely on another environmental cue such as host plant species, and may also integrate information from multiple environmental variables through their combined effect on larval developmental time. To test this, we manipulated developmental time of sympatric populations of three butterflies - Ypthima huebneri, Mycalesis mineus and Melanitis leda - using combinations of temperatures and host plant species. Higher rearing temperature correlated with larger eyespot size in all species. Host plant species independently affected eyespot size. The effects of temperature and host plant differed between species, sexes, and between the forewing and hindwing, suggesting differential selection pressures on eyespots. Nevertheless, information about temperature and host plant species may be integrated through developmental time, because shorter larval development time was correlated with larger eyespots in adults. However, there were exceptions within specific treatments, species, and eyespots. Our results highlight the complex control of eyespot size, which is likely influenced by a network of interacting factors. Our study also demonstrates how sympatric populations of different species interpret similar environmental cues differently.