Insect Science

Tephritid fruit flies of the tribe Dacini rank among the most economically destructive agricultural pests globally, with several Bactrocera Macquart and Zeugodacus Hendel species causing severe losses to fruit and vegetable production across South and Southeast Asia. Bangladesh harbors five dacine species of primary agricultural significance: Bactrocera dorsalis (Hendel), B. carambolae Drew & Hancock, B. zonata (Saunders), B. correcta (Bezzi), and Zeugodacus cucurbitae (Coquillett). Here we present a comparative mitogenomic and molecular phylogenetic framework based on 21 unique mitogenome records retrieved from NCBI GenBank, representing 19 dacine ingroup taxa and two outgroups. Direct parsing of the GenBank sequences confirmed the canonical complement of 13 protein-coding genes (PCGs) and two rRNA genes in all 21 records. Among the 14 Bactrocera ingroup taxa, genome size ranged from 15,273 to 15,977 bp. Whole-genome AT content ranged from 66.6% in Bactrocera tsuneonis to 82.2% in Drosophila melanogaster; the five Bangladesh-relevant dacine pest species showed tightly clustered AT content of 72.9-73.6%. A concatenated alignment of 13,600 nucleotide sites (13 PCGs + 12S + 16S rRNA) was analyzed by maximum-likelihood inference under the GTR+FO model (IQ-TREE v1.6.11; 1,000 ultrafast bootstrap replicates). The ML tree recovers the B. dorsalis complex (UFBoot = 79-100) and places B. correcta and B. zonata as a maximally supported sister pair (UFBoot = 100). This study provides a sequence-verified mitogenomic reference framework for molecular identification and pest surveillance in Bangladesh, and should be interpreted as a curated comparative baseline rather than a population-genomic analysis, as no newly collected Bangladeshi specimens were sequenced.

Many social insects, such as ants, change their behavior stereotypically from nursing to foraging as they age, a concept known as temporal polyethism. Biogenic amines are associated with these specific behaviors, but much about them remains poorly understood in these animals. Many aminergic systems lack anatomical characterization, and little is known about the expression of genes required for the aforementioned behavioral phenotypes. Here, we studied Pogonomyrmex barbatus brains and identified the neurons that produce two relevant amines, dopamine and octopamine, by detecting their synthesis enzymes, tyrosine hydroxylase and tyramine beta-hydroxylase, and their transcripts. We also compared the expression of both genes in young nurses and mature foragers by measuring the fluorescence intensity. Dopaminergic and octopaminergic neurons are predominantly located in the protocerebrum and in the subesophageal zone. Neurons that produce dopamine are also present in the optic lobes, whereas octopamine-producing ones show clusters in the antennal lobes. Both genes are downregulated as the organism ages. A reduction in the expression of these genes might be correlated with the mature workers increased propensity to perform extranidal tasks, such as foraging.

The two-spotted spider mite (Tetranychus urticae) is an extremely polyphagous pest, yet the genetic basis of this adaptive potential remains to be fully elucidated. Since expression quantitative trait loci (eQTLs) provide the genetic basis of numerous phenotypes, we aimed to identify trans-eQTL hotspots underlying T. urticae fitness upon transfer from a common (bean) to a challenging (tomato) host plant. Nonetheless, the identification of trans-eQTLs is complex and often constrained by methodological challenges and high costs. Therefore, we employed a multiparental mapping strategy driven by RNA-seq, enabling us to leverage extensive genetic variation in a cost-efficient manner. A randomly mating population was generated on bean from a small number of genetically diverse, often heterozygous parents, and subsequently transferred to tomato prior to RNA-seq. Upon whole genome sequencing of the parents, RNA-seq of the mapping population individuals was sufficient to reconstruct their genomes as a combination of parental haploblocks. Subsequent eQTL mapping identified 23 distinct trans-eQTL hotspot regions associated with the expression of numerous target genes. The most prominent hotspot on chromosome 3 was associated with approximately 900 genes and showed enrichment for functions related to detoxification and digestion. Furthermore, 4 of these trans-eQTL hotspot genotypes explained significant variation in mite fitness on the challenging host plant. This contrasted a traditional QTL mapping approach, where these genotypes could not be detected due to multiple testing correction. Our study hence offers a powerful strategy for trans-eQTL hotspot screening and the discovery of trait-associated loci in complex, multiparental genetic backgrounds.

Salivary secretions of herbivorous insects contain proteins that modulate plant defence and facilitate herbivory. Despite the broad host range of Spodoptera frugiperda, a major agricultural pest, its salivary molecular arsenal involved in interactions with different host plants remains poorly understood. In particular, the salivary proteins induced during feeding on different host plants and their potential interactions with plant immune components remain largely unexplored. To address this gap, we generated salivary gland transcriptomes from larvae reared on an artificial diet as well as larvae fed on tomato or chickpea plants. Comparative transcriptomic analysis identified salivary genes that were differentially expressed in response to plant feeding compared with the artificial diet. The encoded proteins were subsequently analysed using a secretory protein prediction pipeline to identify host-induced putatively secreted proteins with potential effector functions. Candidate salivary effectors were further investigated using large-scale in silico protein-protein interaction analyses with AlphaPulldown to predict their interactions with immune-pathway associated proteins of tomato and chickpea. This analysis identified multiple putative salivary effector candidates whose expression was induced by plants feeding, with distinct candidate repertoires associated with tomato and chickpea. Predicted interactions between these candidates and plant immune-associated proteins further identified potential host targets. Together, these findings suggest that S. frugiperda may adjust its salivary molecular repertoire in response to the host plant and provide a transcriptome-wide framework for validating effector-target interactions and elucidating the molecular mechanisms underlying S. frugiperda-plant interactions.

In Germany, insecticide use is recommended during mosquito-borne disease outbreaks, yet nationwide data on insecticide resistance in key vector species are scarce. This is particularly relevant for Culex pipiens s.l., a vector of West Nile virus. Here, we provide the first broad-scale assessment of molecular insecticide resistance (kdr and ace-1 mutations) in Cx. pipiens f. pipiens across Germany. We associated insecticide resistances with environmental conditions, potential links with mitochondrial variation of the cytochrome c oxidase I (COI) gene as well as phenotypic resistance (CDC bottle assay with permethrin) of the Frankfurt population with elevated kdr frequencies. Kdr resistance alleles were detected in German Cx. pipiens f. pipiens reaching frequencies of up to 50% in the metropolitan areas of Berlin and Frankfurt am Main. Annual precipitation was negatively associated with kdr allele frequency. Interestingly, ace-1 resistance mutations were only present in the metropolitan area of Frankfurt am Main and in Muggensturm (Rhine valley, southwestern Germany). COI haplotype analyses revealed low genetic variability within German Cx. pipiens f. pipiens populations with no association to the insecticide resistance genotype. Phenotypic assays of the Frankfurt population showed early signs of permethrin resistance, but unmatched genotypic and phenotypic resistance state. This study provides the first broad-scale assessment of molecular insecticide resistance in Cx. pipiens f. pipiens across Germany, establishing a baseline for resistance surveillance and vector control. Further research is needed to identify factors shaping phenotypic resistance, as molecular markers alone may not reliably predict resistance. Since sampling was restricted to urban green spaces, broader sampling across environmental gradients is needed to identify additional environmental effectors.

The red palm weevil, Rhynchophorus ferrugineus, is the most economically destructive palm pest worldwide, threatening livelihoods, food security, and ecosystems across 49 countries. Weevil management currently relies predominantly on chemical insecticides, raising significant environmental and public health concerns. Despite its global agricultural importance, genetic approaches to pest management and the mechanistic basis of genome-editing strategies in Rhynchophorus remain largely unexplored. Here, we employed CRISPR/Cas9 genome editing to disrupt the R. ferrugineus ommochrome biosynthetic pathway -- a multi-enzymatic metabolic cascade that converts tryptophan into ommochrome pigments, including brown, yellow, and red pigments. We targeted two key pathway components: the ATP-binding cassette transporter white and the heme peroxidase cardinal. Both genes were ubiquitously expressed, with peak expression levels in the gut, fat body, and head. Elevated transcript levels were observed across early, mid, and late pupal stages and in 0-, 1-, and 2-day-old adult males and females, consistent with the progression of eye pigmentation throughout the R. ferrugineus life cycle. Embryonic microinjection of a single guide RNA (sgRNA)-Cas9 ribonucleoprotein complex targeting white produced in the Generation-0 (G0) adults with a distinct, white-eyed phenotype with a brownish outer margin, in contrast to the black eyes of wild-type adults. Genome-edited cardinal mutant adults displayed a translucent, brownish-white-eyed phenotype, with white streaks that gradually transitioned to a persistent translucent reddish-brown eye coloration. Mutations in both genes were confirmed in G0 adults by genomic DNA sequencing. Mutant adults were crossed to generate heterozygous G1 (+/-), G2 (-/-, -/+, and +/+), and G3 lines (-/-) with genotypes verified as carrying 2-, 3-, 9-, and 13-nucleotide deletions. A stable, heritable eye-color phenotype was established in homozygous knockout (-/-) G3 lines for both white and cardinal, confirmed by unambiguous indel (insertions/deletions) genotyping. Inheritance analysis revealed that both genes are X-linked, following a classical Mendelian sex-linked pattern: paternal alleles are transmitted exclusively to daughters, while maternal alleles are inherited equally by both daughters and sons. This study establishes the first fully homozygous knockout strain in R. ferrugineus and, by characterizing sex-linked inheritance in a coleopteran system, advances our understanding of how CRISPR/Cas9 can be efficiently applied to destructive palm weevil species. The present study represents the first report of CRISPR/Cas9 genome editing in any weevil (Curculionidae), using white and cardinal as marker genes. These findings provide a valuable platform for functional genomics and genome engineering in R. ferrugineus and offer a translational framework for genome editing in the invasive South American palm weevil, R. palmarum, laying a solid foundation for the development of gene-drive strategies aimed at sustainable palm weevil population control.

Spodoptera frugiperda is one of the most important agronomical pests due to its migratory capacity and broad host range. Since it is resistant to several insecticides, novel control strategies are being explored to control it. In this way, Spodoptera frugiperda Multiple Nucleopolyhedrovirus, a natural pathogen, has been proposed for its biocontrol. In this work, we performed a small RNA-seq on uninfected larvae and larvae infected with SfMNPV to identify expressed miRNA, characterize them, and identify differentially expressed (DE) miRNA in the infected condition. We identified several known and putative novel miRNAs, some of which are encoded in multiple copies and may be expressed within miRNA clusters. We also found 13 DE miRNA, most of them previously reported, two of them are putative novel miRNAs identified in this work. We predicted miRNA targets and found that their putative biological role could be related with processes relevant to the infection such as proliferative and apoptotic pathways, cell cycle regulation, autophagy, DNA damage response (DDR), vesicle transport, cytoskeleton remodelling, JAK/STAT and Toll signaling pathway, and immune response activation, among others. Moreover, we observed that several of the putative targets were hub genes in a predicted protein - protein interaction network. Finally, we found DE miRNA putatively associated with the regulation of viral gene expression, suggesting they might have a role in modulating the infection. Our results contribute to better understanding the miRNA landscape in S. frugiperda, and their putative role upon SfMNPV infection.

Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) is one of the most dangerous palm pests worldwide. Here we report the invasion process of R. ferrugineus in Uruguay. Beyond morphological and molecular identification, we infer the geographic origin of the invasive population, describe the succession of introduced and native palms attacked, provide an easy-to-use key to differentiate the invader R. ferrugineus from the native Rhynchophorus palmarum, and model the ecological niche of R. ferrugineus in Uruguay and neighboring countries. First detected in 2022, the Uruguayan population of the weevil is the first to establish on mainland America, following the earlier island records from Curacao and Aruba. Phylogenetic analysis showed that the Uruguayan R. ferrugineus sequences clustered within a single clade, most closely related to sequences from southern China, and clearly distinct from the sequences of Curacao and Aruba, indicating at least two independent introduction events into the Americas from different source regions. After four years, R. ferrugineus has spread across an area of nearly 80,000 square kilometers and in January 2026 it reached Argentina, invading two points near the border with Uruguay. Over the first two years after the invasion, attacks focused on Phoenix canariensis, yet the three most common native palms in Uruguay, Butia odorata, Butia yatay, and Syagrus romanzoffiana, are currently being attacked. The diagnostic key to differentiate the pair R. palmarum / R. ferrugineus is based on three characters: the tip of the rostrum, the tegminal plate, and the ratio between the interocular space and the width of the rostrum at the base. Niche models showed that Uruguay and the neighboring areas of Argentina and Brazil are suitable for R. ferrugineus, and these are precisely the areas where both the highly susceptible P. canariensis and the native B. odorata, B. yatay, and S. romanzoffiana are present. Neighboring countries should therefore be prepared for the expansion of R. ferrugineus in the short term.

Neuropeptides and their G protein-coupled receptors (GPCRs) control much of insect physiology and behaviour, but in Gryllus bimaculatus, an emerging model and edible insect, receptor sequence similarity hinders the mapping of which peptide each GPCR activates. We re-annotated a chromosome-scale genome (BUSCO 95.3%, from 86.7% on insecta_odb12) with comprehensive curation of 48 neuropeptide precursor families (51 loci, including seven not previously identified) and 134 candidate GPCRs (66 rhodopsin-class, 68 secretin-class), providing a near complete neuropeptide-receptor interactome catalogue. We modelled all 15,946 peptide-receptor pairs with AlphaFold3 and Boltz-2 and scored each interface with pLDDT and ipSAE. Ranking these scores, and cross-checking the top candidate for each family against a receptor phylogeny of known ligand specificity, gave a confident, phylogenetically related receptor for 27 of 35 curated receptor groups. These matches confirm the structural scorings with existing deorphanization data and propose receptors for peptides with no prior functional evidence. The annotation, curated peptide and receptor sets, and ranked complexes are available through CricketBase (https://cricket.annotation.jp), a genome browser with a structure viewer of peptide-receptor complexes, providing a resource for G. bimaculatus endocrinology and a workflow to deorphanize GPCRs in other non-model insects.

Over the course of evolution, many species have adapted to the environmental conditions found at higher latitudes. This is likely also true of the circadian system, which regulates daily behavior and helps measure day length to facilitate adaptation to the seasons, though how the circadian clock adapts to latitude remains largely unknown. Here, we investigated daily activity patterns under long photoperiods and in constant darkness, as well as the underlying circadian clock network, in 52 Drosophila species from around the world. We found a strong, significant positive correlation between the clock's plasticity, measured as the phase difference between morning and evening activity, and the average geographical latitude from which the species originate. The mechanisms underpinning this increase in plasticity differed between species: in the subgenus Siphlodora, the clock weakened with increasing latitude, accompanied by a reduction of the neuropeptide Pigment-Dispersing Factor in the small ventrolateral clock neurons (s-LNv), whereas in the subgenus Drosophila the opposite was true. The subgenus Sophophora, by contrast, showed a negative correlation between circadian plasticity and PDF levels in the s-LNv axons. These results suggest that Drosophila species have evolved diverse, independent strategies to adapt their circadian clock to higher latitudes.

Background: The insect cuticle is a chitin-containing extracellular matrix whose formation requires precise coordination of chitin biosynthesis, fibril organization, and post-synthetic maturation. Although lipids are essential components of the cuticle, the molecular mechanisms linking lipid transport to chitin deposition remain poorly understood. Here we identify TcFabp8, a fatty acid-binding protein in Tribolium castaneum, as a functionally important regulator of chitin synthase 1 (Chs1)-dependent cuticle formation. Results: RNAi-mediated depletion of TcFABP8 caused molting defects, reduced cuticle thickness, loss of apical TcChs1 immunoreactivity, and reduced chitin deposition and organization. The finding that TcCHS1 transcript levels were unaffected by RNAi targeting TcFABP8 suggests that a post-transcriptional step, potentially involving vesicular TcChs1 transport, is affected, thereby impairing chitin synthesis and deposition. Synchrotron X-ray diffraction analysis of adult elytra revealed that TcFabp8 depletion preserved characteristic -chitin-associated scattering features, but altered chitin fibril accumulation, crystalline coherence, and the spatially ordered alignment of fibrils within the cuticular matrix. The TcFabp8 gene locus encodes splice variants yielding different N-terminal architectures: TcFabp8X1 carries a Sec/SPI signal peptide which is absent in TcFabp8X2 and TcFabp8X3. Immunocytochemistry using TcFabp8-specific antibodies detected intracellular signals in subapical cytoplasmic puncta and extracellular signals within the cuticle layers, which partially colocalized with Nile red fluorescence indicating lipid-rich environments. Conclusions: Together, our data demonstrate that TcFabp8 is a critical facilitator of TcChs1-dependent chitin deposition and extends functional connection between lipid transport and chitin biosynthesis in insects.

AbstractMetarhizium anisopliae is an important entomopathogenic fungi used in biological control of agricultural pests, but its commercial application is limited by relatively slow host mortality. This study aimed to engineer a chimeric protease (cPr1A) with enhanced binding affinity and protease activity against insect cuticle. We hypothesized that stronger cuticle binding would increase local enzyme concentration at the cuticle surface and thereby enhance cuticle degradation. To achieve this, the Bombyx mori chitin-binding domain (BmCBD) was fused to the C-terminus of the Pr1A protease from M. anisopliae. Recombinant Pr1A and cPr1A were expressed in Escherichia coli, purified by Ni-NTA affinity chromatography. Binding and protease activity were assayed in triplicate using Samia ricini cuticle powder as substrate. Results are presented as mean +/- SEM. The chimeric protease cPr1A showed a 28.9% increase in cuticle binding compared to wild-type Pr1A (15.81 +/- 1.97 vs. 12.27 +/- 2.13 g bound protein/mg cuticle powder; p < 0.002) and a 35% increase in protease activity (0.343 +/- 0.08 U/mg vs. 0.254 +/- 0.06 U/mg; p < 0.03). These results indicate that cPr1A is a promising candidate for overexpression in M. anisopliae to enhance cuticle degradation and potentially improve fungal virulence against insect pests.

The generalist Helicoverpa armigera and the specialist Helicoverpa assulta are closely related noctuid pests and are among the few insect herbivores capable of feeding on and damaging hot pepper fruits, which contain the defensive compound capsaicin. Cytochrome P450 monooxygenases (P450s) contribute to the metabolism of plant defensive compounds and can facilitate insect adaptation to chemically defended host plants. Here, we identified CYP6AN1 in H. assulta (HassCYP6AN1) and comparatively characterized the CYP6AN1 orthologs from H. armigera (HarmCYP6AN1) and H. assulta. RACE identified one full-length HarmCYP6AN1 transcript and three full-length HassCYP6AN1 transcript isoforms. The HassCYP6AN1 isoforms contained distinct 5' UTRs generated by alternative transcription initiation and splicing but shared an identical coding sequence. Sequence comparisons and phylogenetic analysis supported their assignment as orthologs. Constitutive CYP6AN1 expression was higher in the H. assulta midgut, whereas dietary capsaicin significantly induced CYP6AN1 expression in the H. armigera midgut. Recombinant CYP6AN1 proteins were co-expressed with NADPH-cytochrome P450 reductase in Escherichia coli, and their substrate-metabolizing activities were evaluated using HPLC-based depletion assays. Both orthologs metabolized capsaicin, but HarmCYP6AN1 exhibited an approximately 2.3-fold higher depletion activity than HassCYP6AN1 under the conditions tested. HarmCYP6AN1 also showed P450-content-dependent xanthotoxin depletion, whereas no detectable xanthotoxin metabolism was observed for HassCYP6AN1. These findings establish CYP6AN1 as a component of the capsaicin-metabolizing repertoire of both species and reveal substantial divergence between the orthologs in transcript organization, expression regulation, catalytic activity, and detectable substrate range.

Aim To investigate how repeated historical connections between continental islands and the mainland have shaped the phylogeographic structure and genetic diversity of populations, using the widespread water strider Aquarius paludum as a model. Location Japan Taxon Water strider Aquarius paludum (Insecta: Hemiptera: Gerridae) Methods We analysed mitochondrial (COI and COII) and nuclear (ITS1) DNA sequences from populations across the Japanese archipelago and the Eurasian continent. Phylogenetic and population genetic analyses were used to reconstruct phylogeographic structure and infer demographic history. Results Western Japanese populations exhibited nucleotide diversity comparable to that of continental populations despite their insular distribution. Bayesian phylogenetic analyses identified two major mitochondrial haplogroups (A and B) that frequently co-occurred across the Japanese archipelago. Haplogroup A, which is rare on the Eurasian continent, occurred at high frequency in Japan and showed pronounced isolation by distance, whereas haplogroup B showed only weak but significant isolation by distance and was significantly more frequent in populations closer to the coast. These contrasting spatial patterns within species indicate distinct demographic histories for the two mitochondrial lineages. Main conclusion Repeated colonization from the Eurasian continent and the long-term coexistence of mitochondrial lineages with different demographic histories have shaped the pattern of genetic diversity of A. paludum in the Japanese archipelago. Our findings exemplify how continental islands can accumulate genetic diversity through lineage accumulation and secondary contact, which produces an intraspecific phylogeographic pattern comparable to those observed during an early phase of the taxon cycle between species.

Nesidiocoris tenuis is an important zoophytophagous mirid bug used as a biological control agent in agriculture, and breeding efforts based on genomic information aim to increase its utility. Visible eye-color mutants are useful genetic markers because they are easily distinguishable and are therefore widely used in insect genetics and genome editing studies. Here, we investigated the genetic basis of a spontaneous red-eye mutant identified in a laboratory strain of N. tenuis. Classical crossing experiments suggested that the red-eye phenotype is controlled by a single recessive locus. RNA-seq and RNA interference (RNAi) analyses identified scarlet and cinnabar as the primary candidate genes associated with the phenotype. Further genomic analysis revealed a large deletion and insertion within exon 5 of the mutant scarlet allele, potentially causing exon skipping and disrupting transporter structure. The insertion pattern is consistent with a microhomology-mediated break-induced replication (MMBIR)/fork stalling and template switching (FoSTeS)-like event that may have been generated through polymerase{theta} -mediated repair. Together, these findings identify the causative mutation underlying the red-eye phenotype and provide a useful visible marker for future functional genetic studies and genome-assisted breeding in N. tenuis.

Stingless bees are key pollinators of native and cultivated plants, and their management mostly for honey and hive commercialisation has become an increasingly popular practice in Brazil. Hives are commonly kept close together and visually similar in meliponaries, a practice that favours drifting, i.e., the return of foragers to a foreign nest. Distance between hives and layout have been identified as drivers of drifting in the Western honeybee, but evidence for stingless bees, the largest group of social bees, remains scarce. Additionally, stingless beekeepers frequently associate drifting with weakened colonies, uneven honey production, worker fighting, and colony population imbalances. We investigated the effects of hive layout on foraging traffic and drifting in the stingless bee Melipona quadrifasciata. We compared forager traffic across six layouts varying in distance, colour and entrance orientation. Then, using RFID tags, we tracked drifting across three layouts with the same inter-hive distance but different designs: visually similar hives, hives with opposite entrance orientation, and hives painted with distinct colours. Forager traffic was lowest in the visually similar layout during the first two weeks of monitoring, which is consistent with greater disorientation in the absence of clear visual cues. Hive position was a key driver of drifting behaviour across all layouts, with bees from edge hives drifting considerably less than those from inner hives. Drifting decreased considerably in hives with different colours (37.6%) and hives with entrances in opposite directions (48.1%), compared to similarly looking hives with entrances in the same direction (59.5%). Therefore, our findings highlight practical low-effort strategies for stingless beekeepers to reduce forager loss, pathogen spread, and productivity losses.

BACKGROUND: Aphids damage crops through sustained feeding and by rapid transmission of plant viruses, processes that are not effectively prevented by conventional insecticides. The sugarcane aphid (Melanaphis sacchari), an invasive pest of sorghum in the United States, can inoculate non-persistent viruses within minutes of probing. Disrupting feeding phases represents an alternative strategy in plant disease and integrated pest management. ATP-binding cassette transporters (ABC transporters) influence insect physiological performance, but their role in regulating aphid feeding behavior relevant to crop damage and virus transmission remains unknown. This study evaluated whether ABC transporter activity alters feeding phases of M. sacchari on sorghum. RESULTS: Aphids exposed to ABC transporter modulators via artificial diet and monitored using Electrical Penetration Graph (EPG) recordings showed significant reductions in salivation in E1 phase, compared with controls (P < 0.05) and an increased duration in xylem phase when treated with elacridar, an ABC transporter inhibitor. Aphids treated with dexamethasone, an ABC transporter activator, exhibited increased time spent in pathway phase compared to the controls. ATPase assays also showed significant variations in modulator-treated samples compared to the controls. CONCLUSION: These results demonstrate that transporter modulators alter feeding behaviors which might lead to reduced crop damage/virus transmission, including pathway activities, salivation, and xylem ingestion. This study opens the path to identify ABC transporters as regulators of feeding phases, and to advance the understanding of aphid-plant interactions. This new knowledge will support the development of feeding-based pest management strategies to reduce crop damage and virus transmission.

Behavioral thermoregulation allows animals to reduce the physiological costs associated with variation in the thermal environment, yet little is known about how chimpanzees respond behaviorally to the cool and humid conditions of tropical montane forests. We examined how microclimatic conditions influenced resting posture, sun/shade use, substrate use, vertical position within the canopy, and day nest use in eastern chimpanzees (Pan troglodytes schweinfurthii) in Nyungwe National Park, Rwanda. From March 2024 to February 2025, we collected 5,661 individual behavioral records during 486 contact hours and paired behavioral observations with measurements of ambient temperature, water vapor pressure, wind speed, and rainfall. Bayesian mixed models showed that temperature was the most consistent climatic correlate of resting behavior. Under cooler conditions, chimpanzees were more likely to adopt heat conserving postures, particularly curled and huddled postures, and to use day nests. As temperature increased, chimpanzees increased their use of shade, shifted from arboreal to terrestrial resting, and used lower canopy strata more frequently. Higher wind speed was also associated with reduced use of the upper canopy, whereas rainfall, water vapor pressure, and fruit availability generally showed weaker or behavior-specific associations. These findings indicate that chimpanzees in a cool montane forest flexibly adjust posture, solar exposure, substrate use, vertical position, and day nest use in relation to local thermal conditions. Resting behaviour may therefore provide an important context for behavioral thermoregulation, extending our understanding of chimpanzee thermal ecology beyond the warmer lowland and savanna habitats that have received most previous attention.

Fluctuating asymmetry (FA) is widely used as a proxy for developmental instability, although reduced rather than increased FA, has occasionally been reported under particularly challenging conditions, possibly because environmental filtering removes less developmentally stable individuals. Here, we investigated temporal variation in wing shape asymmetry in males of Drosophila sturtevanti collected in 2022, 2024, and 2026 at the same sampling site, an urban Atlantic Forest fragment. Sampling in 2022 and 2026 were completed during single field expeditions in early April, whereas in 2024 repeated collections were required until mid-May because of markedly low capture success. We therefore examined whether this difference was associated with unusual environmental conditions and whether FA was higher in 2024, as expected under greater developmental perturbation. Daily temperature and relative humidity were examined from early March onward, encompassing approximately one month before adult emergence. The 2024 sampling period was warmer and drier than the corresponding periods in 2022 and 2026 and coincided with the final phase of the strong 2023-2024 El Ni&ntildeo event. Contrary to our prediction, FA was significantly lower in 2024. The magnitude of directional asymmetry remained similar among years, although the spatial pattern of the DA vector differed between 2024 and 2026. The coincidence of reduced capture success and reduced FA is consistent with the hypothesis that adverse conditions may impose demographic filtering, such that individuals expressing greater developmental instability are less likely to contribute to the sampled adult population.

Odors allow animals to evaluate resources and risks, but the neural and inherited consequences of experience with ecologically meaningful odors remain poorly understood. Since both parasitoids and entomopathogenic fungi are widely used as agents in integrated biocontrol, we asked whether exposure to pathogen-associated volatiles can reassign odor value in a parasitoid wasp and whether the acquired bias is transmitted to descendants. Adult female Scleroderma guani were exposed, without host contact, to volatiles from Beauveria bassiana-infected hosts or to methyl cinnamate (MC), a representative component of the infected-host odor. Twelve-hour exposure shifted subsequent choices away from infected-host odor and MC, whereas shorter exposure produced different effects, indicating duration-dependent olfactory plasticity. The shift occurred without an explicit reward or punishment and is therefore consistent with non-associative learning. Unexposed F1 and F2 descendants of MC-exposed females expressed the same avoidance bias. MC stimulation elicited stronger calcium responses in mushroom-body regions of trained females and their descendants. Head transcriptomes identified reduced expression of the crustacean cardioactive peptide receptor (CCAPR) as a shared molecular signature, and CCAPR RNA interference phenocopied the odor-avoidance behavior. Finally, maternal treatment with sinefungin, a broad S-adenosylmethionine-dependent methyltransferase inhibitor, left maternal behavioral shift intact but abolished the F1 bias, implicating a methylation-sensitive process in transmission. Together, these results reveal that a pathogen-associated odor can induce durable, cross-generational reweighting of olfactory value in a non-model insect and identify candidate neural and neuropeptidergic mechanisms linking sensory experience to inherited behavior, and providing a new perspective on utilizing training in integrated biocontrol as well.