Many animals live in cooperative social groups. The success of social animals is thought to be influenced by both an animal's own characteristics and by the characteristics of its social partners. As a result, some social animals may devote substantial time and energy to assessing potential partners. Here, we study the process of social group formation in Polistes fuscatus paper wasps. Prior to founding nests, wasps engage in extended social partner sampling where they synchronously "shop" for co-foundresses. We quantify wasp behavior during partner sampling using day censuses and recording aggregations. We found that wasps preferentially aggregated at specific locations, without resources or nests, consistent with the formation of a "social lek." In aggregations, wasps engaged in a range of aggressive interactions. At the beginning of the shopping period, wasps engaged in more intensely aggressive behavior and they observe conspecifics fight. Later in the shopping season, wasps engaged in less aggressive behavior. Overall, P. fuscatus devote substantial time and energy to a period of partner selection prior to nest foundation that is suggestive of lekking.
Successful endoparasitism requires parasitoids to overcome the host immune defense, encapsulation. However, the mechanisms governing encapsulation, particularly its initiation, remain poorly understood, limiting our understanding of coevolution between parasitoids and their hosts and constraining the broader application of parasitoids in biological control. Our results showed that Ostrinia furnacalis plasma factor Immulectin-5 (IML-5) is essential for nonself recognition of hemocytic-mediated encapsulation of Macrocentrus cingulum larvae. Upon incubation with host plasma, three OfIMLs specifically bound to the wasp larval surface. Among them, OfIML-5, predominantly expressed in the fat body, was secreted into the plasma and strongly upregulated upon wasp larval exposure. RNAi-mediated knockdown or antibody-mediated neutralization of OfIML-5 significantly impaired host encapsulation ability. Consistently, CRISPR/Cas9 knockout of OfIML-5 decreased the encapsulation rate from 73.5% to 17.9%. Furthermore, OfIML-5 simultaneously binds to the surface of wasp larvae and hemocytes, suggesting that it possibly acts as a recognition factor and adaptor to promote hemocytic encapsulation. Co-immunoprecipitation assays indicated that OfIML-5 interacts with OfIML-3 and may participate in the transduction of nonself signals. Finally, we provide preliminary evidence that miR-34-5p secreted by M. cingulum targets the OfIML-5 gene and suppresses its expression, thereby attenuating host encapsulation. Our results indicate that OfIML-5 interacts with OfIML-3 and may function to transmit nonself signals to hemocytes, thereby promoting encapsulation against parasitoid wasp. Meanwhile, parasitic wasp M. cingulum secretes miR-34-5p, which targets OfIML-5 and suppresses host encapsulation. These findings help clarify the intricate immune interaction strategies between parasitoid wasps and their hosts. © 2026 Society of Chemical Industry.
Insect-virus associations have been studied extensively in the context of pathogenic viruses transmitted by insects, whereas research on nonpathogenic viruses remains relatively scarce. Recently, we discovered three nonpathogenic RNA viruses in the parasitoid wasp Anagyrus vladimiri: AnvRV, AnvDV, and AnvIfV. Here, using transmission electron microscopy, we detected AnvRV in the wasp oocytes and in a distinct group of cells in the ovaries, which we termed "satellite cells," but not in the venom gland or venom reservoir, indicating that AnvRV is transmitted transovarially. Next, we analyzed gene expression in AnvRV-infected and uninfected wasps and found that AnvRV modulates the immune response and alters venom composition. Notably, the NF-κB inhibitor gene was upregulated in the wasp ovaries, where AnvRV is localized, suggesting that AnvRV locally suppresses the immune response of A. vladimiri to facilitate its transmission. Next, we studied the prevalence of the three viruses in field populations of A. vladimiri and its hosts, Planococcus citri and Planococcus ficus. AnvRV was absent from both mealybug species and detected at low prevalence in A. vladimiri, whereas AnvDV and AnvIfV were consistently present in P. citri. Lastly, by datamining of public RNAseq data sets, we investigated the prevalence of these viruses in other parasitoid species and revealed only a few related viruses. Taken together, we postulate that AnvRV is an active symbiont of A. vladimiri, influencing host gene regulation. These findings provide new insights into the diversity of insect-virus interactions and their potential roles in shaping parasitoid biology. Viruses likely represent the majority of insect symbiotic microorganisms. Yet, viral symbionts and their interactions with insect hosts were less studied, mostly due to technical difficulties stemming from their small size and lack of universal markers. Although viral symbionts are usually perceived as pathogens, there are clear instances in which they are beneficial to their hosts, providing functions that are essential in some cases and conditionally beneficial in others, shaping insect ecology and evolution. This study provides several pieces of the puzzle on the road to understanding the complex interactions within the multi-trophic system consisting of a parasitoid wasp, its mealybug host, and a double-stranded RNA virus. This system may serve as a case study of viruses' effect on insects and broaden our understanding of the possible effects of viruses on other arthropods.
The obligate mutualism between Ficus and its pollinating wasps provides a suitable system to investigate these dynamics because it encompasses two contrasting pollination modes: active and passive. Here we compared pollen traits in an actively pollinated fig tree, Ficus citrifolia, and a passively pollinated species, F. obtusiuscula, examining pollen both at anther presentation and after deposition on the bodies of their pollinating wasps. Pollen morphology, hydration-related behavior, cytology, and reserve composition were characterized using scanning electron microscopy (conventional and modified), light and transmission electron microscopy, histochemical assays, and viability tests. Across species, pollen traits at anthesis showed broad overlap in morphology, viability and major reserve classes, indicating that these characteristics are not consistently predicted by pollination mode alone. In both species, pollen was bicellular, harmomegathic and highly viable at presentation, consistent with resilience during transport. The main divergence emerged after pollen transfer to the pollinator. In the actively pollinated species, pollen recovered from wasp thoracic pockets exhibited pronounced intracellular remodeling, including vacuolization, starch depletion, lipid redistribution and localized cytoplasmic degradation. By contrast, pollen of the passively pollinated species retained a comparatively stable cytological organization after transport despite changes in reserve distribution. These results suggest that the more pronounced cytoplasmic reorganization observed in the pollen of the actively pollinated species after deposition on the wasp body may represent a preparatory phase for rapid germination following pollination, reflecting the stronger dependence of larval development on successful flower fertilization in actively pollinated figs. More broadly, our study provides the first comparative account of pollen structural and cytophysiological dynamics on fig-wasp bodies, linking pollen cell biology to pollinator-mediated dispersal and highlighting how different pollination strategies may impose distinct selective pressures on male gametophytes.
Wasp venoms possess complex compositions and diverse bioactivities, making them potential pharmacological sources. In this study, venoms from four wasp species (Vespa mandarinia, V. velutina, V. basalis, and Provespa barthelemyi) were collected by electrical stimulation and analyzed using liquid chromatography-tandem mass spectrometry. A total of 681 peptides were identified, nearly 90% of which had not been previously reported. Comparative analyses revealed pronounced species-specific signatures at both peptide and peptide family levels. Sequence-based analyses indicated that peptide release is consistent with targeted proteolytic cleavage patterns, exhibiting features resembling known substrate preferences of metalloproteases and serine proteases, rather than stochastic degradation. Bioinformatic predictions identified 291 peptides with potential bioactive properties spanning multiple functional categories, with angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP4) inhibitory activities being the most prominently represented. Among these, eight ACE inhibitory peptides and seventeen DPP4 inhibitory peptides were prioritized as candidates based on predicted safety profiles, and sequence-based analysis further identified ten putative cryptides. Overall, this study establishes the first comparative peptidomic dataset across four wasp venoms, providing insights into peptide diversity, inferred generation patterns, and predicted activities. SIGNIFICANCE: Venoms are rich sources of biologically active molecules and have historically provided templates for clinically used therapeutics. Although major protein toxins have been extensively characterized, the endogenous low-molecular-weight peptide fraction remains comparatively underexplored, particularly in social wasps, and systematic comparative resources remain limited. Venom peptidomic datasets inherently contain multiple layers of biological information, including diversification patterns, peptide origin, and potential bioactivity, yet these aspects are often interpreted independently. By integrating these dimensions, this study establishes a multi-level analytical framework for extracting biological insights and function-related information from venom peptidomes. The identification of consistent cleavage patterns suggests a degree of regulation in peptide generation, shifting the interpretation of venom peptides from degradation by-products toward biologically organized repertoires. Moreover, candidate prioritization illustrates how peptidomic datasets can generate experimentally testable functional hypotheses rather than serving solely as descriptive catalogs. The resulting dataset serves as a reference resource for cumulative comparative analyses. The analytical framework presented here also provides a transferable strategy for functional peptide discovery in other complex secretions.
Social wasps are generalist predators that play key roles in biological control and also contribute to pollination. However, when foraging in contaminated agricultural fields and surrounding areas, they are exposed to a wide range of insecticides, similarly to bees, and therefore share similar exposure pathways. Previous studies have shown that Polybia paulista is more sensitive to the insecticide thiamethoxam than several bee species, including Apis mellifera. Among the different classes of insecticides, phenylpyrazoles such as fipronil are widely used in pest management due to their neurotoxic mode of action and systemic activity. However, their effects on social wasps remain poorly understood. Therefore, this study tested the hypothesis that chronic exposure of P. paulista to sublethal concentrations of fipronil reduces survival and affects mobility. The mean lethal concentration (LC50) was determined and used to define sublethal concentrations (LC50/100 and LC50/10). Survival was monitored until death to estimate the mean lethal time (LT50), and mobility was subsequently evaluated. Exposure to both sublethal concentrations significantly reduced survival compared with unexposed wasps. In addition, wasps exposed to LC50/10 showed reduced mobility after 48 h of exposure.
This study aims to preliminarily investigate the regulatory role of the PI3K/Akt/NF-κB signaling pathway in the process of wasp venom-induced acute liver injury. Rats were randomly divided into four groups using a random number table: Control group, PDTC group, ALI group, and ALI+PDTC group. Significant changes were observed in the ALI group in the following aspects: (1) Behavioral Changes: Rats exhibited reduced activity and agitation 6 h after toxin exposure, with gradual relief observed after 24 h. (2) Biochemical Tests: The ALT and AST levels were significantly elevated at all time points (p < 0.05). (3) Pathological Changes: Liver cord structure disorganization, extensive necrosis, and neutrophil infiltration were observed, indicating time-dependent liver injury. (4) Inflammatory Cytokines: Levels of IL-6, TNF-α, and IFN-γ were significantly increased (p < 0.05), while IL-10 levels were decreased (p < 0.05). (5) Protein Expression: The expression of PI3K, Akt, and NF-κB p65 proteins was significantly elevated (p < 0.05). No significant differences were found between the Control and PDTC groups (p > 0.05), while the ALI+PDTC group showed notable relief. This study successfully established a rat model of acute liver injury induced by wasp venom and found that the aberrant activation of the PI3K/Akt/NF-κB signaling pathway may contribute to liver injury progression by promoting inflammation. The NF-κB inhibitor PDTC significantly alleviated liver injury, an effect possibly associated with suppression of this pathway, providing a new theoretical basis for targeted treatment of secondary liver injury caused by clinical wasp stings.
Wasp stings are benign, generally associated with localized pain and allergic reactions, but in rare cases, they may trigger life-threatening systemic toxicity, culminating in multiorgan dysfunction syndrome (MODS). We present the case of a 23-year old female who developed MODS following multiple wasp stings, manifesting with rhabdomyolysis, acute kidney injury (AKI), hepatic dysfunction, and necrotic skin lesions. Laboratory evaluation showcased markedly elevated creatine kinase (CK), liver enzymes, and renal parameters. She was managed with Adrenaline, corticosteroids, aggressive intravenous fluids, and supportive hepatorenal measures, leading to complete recovery within a month. This case serves as a reminder that rapid intervention and fast-paced multidisciplinary management can mean the difference between complete recovery and a fatal outcome.
Cooperative breeders are defined by a division of reproductive labour among group members that can respond flexibly to changing conditions via phenotypic plasticity. But such plasticity can be costly and is likely to be influenced by previous experience. Polistes paper wasps live in small societies where non-reproductive (worker) and reproductive (queen) individuals can switch roles throughout adulthood. Such plasticity in reproductive roles positions them as important models for social evolution. However, the limits of their individual-level plasticity have not been fully tested. We experimentally forced queens and workers of Polistes canadensis to nest alone, requiring them to express reproductive and non-reproductive characteristics simultaneously. At the behavioural level, although all isolated wasps laid eggs and foraged, ex-queens were less good than ex-workers at brood rearing. We attribute this to subtle differences in neuroplasticity. While brain transcription of both ex-queens and ex-workers changed in response to the manipulation, converging on a state intermediate to that of control queens and workers, ex-queens did not upregulate some key molecular processes required for expression of an effective worker phenotype. Our findings demonstrate that both Polistes queens and workers can exhibit behavioural, physiological and molecular plasticity, but reveal how previous life history can impose limits to that plasticity.
We present a genome assembly from an individual female Nysson trimaculatus (solitary wasp; Arthropoda; Insecta; Hymenoptera; Crabronidae). The assembly contains two haplotypes with total lengths of 301.31 megabases and 403.46 megabases. Most of haplotype 1 (86.44%) is scaffolded into 28 chromosomal pseudomolecules. Haplotype 2 was assembled to scaffold level. The mitochondrial genome has also been assembled, with a length of 25.2 kilobases. This assembly was generated as part of the Darwin Tree of Life project, which produces reference genomes for eukaryotic species found in Britain and Ireland.
We present a genome assembly from an individual female Symmorphus gracilis (Figwort Mason Wasp; Arthropoda; Insecta; Hymenoptera; Vespidae). The assembly contains two haplotypes with total lengths of 220.03 megabases and 217.14 megabases. Most of haplotype 1 (92.39%) is scaffolded into 6 chromosomal pseudomolecules. Haplotype 2 was assembled to scaffold level. The mitochondrial genome has also been assembled, with a length of 19.73 kilobases. This assembly was generated as part of the Darwin Tree of Life project, which produces reference genomes for eukaryotic species found in Britain and Ireland.
Two new species, Aprostocetus eucalyptus Zheng & Yefremova sp. nov. (Hymenoptera: Eulophidae) and Megastigmus bipolaris Zheng & Yefremova sp. nov. (Hymenoptera: Megastigmidae), were discovered on populations of the invasive gall wasp Ophelimus bipolaris (Hymenoptera: Eulophidae) infesting Eucalyptus in Guangxi, China. An integrative taxonomic approach combining morphological characterization and 28S rRNA-based phylogenetic analysis was used for species identification and classification. Detailed morphological descriptions, illustrations, and an identification key for both sexes are provided. Field parasitism data confirm their potential as native natural enemies, supporting their utility for the biological control of this economically important pest.
Understanding how island characteristics influence the establishment and impact of invasive species and their natural enemies could inform both island biogeography and biological control theory. We studied the occurrence and relative abundances of the globally invasive vinegar fly, Drosophila suzukii, and its recently introduced larval parasitoids, Leptopilina japonica and Ganaspis kimorum, across islands with varying sizes and levels of human-mediated transport in the Gulf and San Juan Islands of British Columbia (Canada) and Washington State (USA). Across 2 years and 58 sites, we collected D. suzukii and its parasitoids from wild blackberry, Rubus armeniacus, fruit. We predicted that parasitoids were more likely to be present on larger islands with higher levels of human activity and higher D. suzukii densities, and that the less specialized parasitoid species (L. japonica) would be more likely to establish on islands. We detected D. suzukii across all islands, indicating widespread establishment of this invasive pest. In contrast, we observed parasitoids on fewer than half of the islands. Leptopilina japonica was the only parasitoid of D. suzukii detected on islands. Parasitoid presence was significantly positively associated with host density and marginally positively associated with island area, but not average annual vehicle ferry traffic (an indicator of human-mediated propagule pressure). Parasitism levels were low throughout the study region and we did not observe lower relative abundances of D. suzukii on islands where parasitoids were present-in fact, the relative abundance of D. suzukii tended to be higher on islands where the parasitoid L. japonica was detected. These findings suggest that island characteristics, host density, and a consumer's host specificity may be associated with the spread of natural enemies from mainland areas to islands, but that the natural enemy's presence may not inevitably result in pest population suppression on islands, at least over the short term.
The morphology of insect visual system was often linked with resource type and resource-finding strategies. Since larger compound eyes and ocelli altogether improve image resolution, capturing light and motion perception, one may expect that insects specialised in chasing very mobile resources possess such morphological optimisation. We tested this hypothesis in females of Apoidea (Hymenoptera), which include bees (which just land on flowers to collect pollen), wasps hunting for weakly mobile prey that are not chased in flight (e.g., beetles, aphids) (LMr-species) and wasps which prey upon highly-mobile flying prey (e.g., flies, bees) (HMr-species). By analysing 77 species, we have found that, once taken into account the head width, HMr- and LMr-wasps did not differ in eye size, but had larger eyes than bees. Median ocellus diameter, on the other hand, did not differ between bees and wasps, though HMr-wasps had larger ocelli than LMr-wasps. The observed variations were largely dependent on head width, with the eye enlargement being faster in wasps than in bees as the head size increased. Phylogenetically-corrected models highlighted a strong effect of common ancestry on morphological variation but confirmed the significant effect of food mobility for the relative eye size. Ancestral state reconstructions suggested a shift to relatively smaller eyes in correspondence with the shift to pollen provisioning, while things seemed to be more complex with the relative ocellar size, likely because of the negative allometry of this trait, especially strong in bees. We may conclude that the need to hunt rapidly moving prey in flight has likely contributed to the evolution of the visual system in Apoidea.
Wiskott-Aldrich Syndrome protein (WASp) is an actin nucleation-promoting factor that regulates the dynamic rearrangements of the actin cytoskeleton following T cell receptor (TCR) engagement. Recognition of antigen by T cells leads to TCR signal transduction, which involves the phosphorylation of various proteins in close proximity to the TCR, known as proximal TCR signalling. Proximal TCR signalling is initiated by the phosphorylation of signalling proteins including CD3 subunits, lymphocyte-specific protein tyrosine kinase (Lck) and zeta-chain-associated protein kinase 70 (ZAP70). Activation of these proteins initiates the formation of a signalosome, which is required for actin polymerisation and gene expression. The role of WASp in relation to proximal TCR signalling is largely unknown. In the present study, we knocked out WASp in Jurkat T cells using the CRISPR-Cas9 system to evaluate its effect on proximal TCR signalling. As expected, Jurkat T cells lacking WASp exhibited impaired actin polymerisation. Following TCR triggering, phosphorylation of CD3, Lck and ZAP70 was markedly reduced. There was also a failure in the recruitment of Lck and ZAP70 to the TCR. Impaired proximal TCR signalling (reduced tyrosine phosphorylation of CD3, Lck and ZAP70) was exclusively associated with decreased CD69 and CD25 expression. Therefore, besides its role in actin rearrangement, WASp is also required for proximal TCR signalling.
Consumer-resource interactions can shift from exploitative to mutualistic when reciprocal benefits such as nutrient exchange offset the costs of damage or mortality, though these benefits are often difficult to detect. Carnivorous pitcher plants are typically viewed as exploiters of arthropod prey, yet most visitors escape capture and may gain access to concentrated, nutrient-rich rewards. This raises the possibility that pitcher plants and their arthropod visitors engage in an indirect mutualism in which both insects and plants incur costs but reap net nutritive benefits. However, evidence that potential prey species derive measurable nutritional benefits from pitcher plants is lacking. To address this knowledge gap, we measured nitrogen isotopic enrichment in vespulid wasps residing in dense stands of the naturally 15N-enriched pitcher plant Darlingtonia californica relative to wasps from adjacent forest patches. Wasps occupying pitcher fens exhibited elevated δ 15 N $$ {\updelta}^{15}\mathrm{N} $$ values, indicating assimilation of 15N-enriched nitrogen originating from Darlingtonia-either directly through nectar consumption or indirectly via pitcher-enriched arthropod prey. These findings are consistent with reciprocal nutrient exchange between carnivorous plants and local insect populations.
Infochemicals mediating intraspecific (pheromones) and interspecific (kairomones) interactions play critical roles in parasitoid host location. Yet how they interact to guide foraging behavior remains poorly understood. This study investigated chemical communication between the parasitoid wasp, Chouioia cunea and its host, the fall webworm, Hyphantria cunea, with a focus on the integration of conspecific signals and host-derived cues. Volatile collection and gas chromatography-mass spectrometry (GC-MS) analyses identified 14 and five compounds from wasps and parasitized host pupae, respectively. Chouioia cunea females showed significant attraction to odors from both conspecific females and parasitized host pupae in behavioral assays conducted with a Y-tube olfactometer. Further, wasps showed electroantennographic responses to 18 of the 19 identified compounds, as well as attraction to their synthetic blend. However, female wasps showed strong oviposition preference for unparasitized over parasitized pupae. These results demonstrate that C. cunea integrates conspecific pheromones and host-derived kairomones to guide host location, but uses additional cues for oviposition, to avoid superparasitism. These findings provide new insight into parasitoid chemical ecology and serve as a basis for developing improved attractants for biological control. © 2026 Society of Chemical Industry.
While sesame (Sesamum indicum L.) is one of the oldest domesticated oilseed crops, it has only recently become a new and emerging crop for the southeast USA. As little is known about the insect fauna of sesame in the United States, it will be important to document insect communities now while management programs are still being developed. Here, we provide the first survey of beneficial insects, including pollinators and potential natural enemies, for sesame in the United States. Beneficial insects within sesame fields were surveyed in 2023 at 2 locations in North Carolina, United States using 2 sampling methods: visual identification and sticky cards. During visual surveys, insects were field identified, with up to 5 physical specimens collected per species for identification verification. Pollen was then removed, identified, and quantified from collected specimens. Potential natural enemies collected on sticky cards were categorized as stilt bugs (Hemiptera: Berytidae: Jalysus spinosus Say), dragonflies (Odonata: Anisoptera), lady beetles (Coleoptera: Coccinellidae), and wasps (Hymenoptera: Apocrita). We found 18 bee (Hymenoptera: Anthophila) species visiting sesame flowers, with honey bees collecting the most sesame pollen per specimen. Wasps were the most abundant natural enemy category, with over 100 wasps collected at some sampling events. The information from this study can be used to ensure beneficial insect communities are protected as sesame production is expanded in the United States.
Cryptic species present major challenges for biodiversity and evolutionary research due to the morphological similarity and frequent lack of available genetic and ecological data. In parasitoid wasps, this is especially true for lineages with limited taxonomic and genetic sampling and unclear geographic ranges. Here we reconstruct the phylogeny of Cotesia wasps parasitizing Melitaeini butterflies, including two cryptic species complexes (Cotesia acuminata agg. and C. melitaearum agg.). Using a ten-gene dataset from samples collected in Europe, Asia, and North America, we inferred relationships among 22 Cotesia species using maximum likelihood. We also included non-Melitaeini associated Cotesia to assess whether the parasitoids of Melitaeini form a monophyletic group. Our analyses yielded a highly supported phylogeny, revealing four major clades, three of which included the Melitaeini associated species. This confirms that the Cotesia parasitizing Melitaeini butterflies are polyphyletic, likely resulting from independent host shifts across the genus. Each clade is further subdivided into subclades corresponding to the different cryptic species complexes, clarifying previously unresolved relationships. These results provide a robust framework for future studies on the evolution, ecology, and host use dynamics of Cotesia wasps and highlight the utility of multi-locus data for resolving phylogenies in morphologically cryptic taxa.
The thermal conditions experienced during development can affect host-associated microbial communities. We still know little about whether such effects similarly persist across life stages between different species. In particular, it is unclear if the bacterial communities of closely interacting species, such as hosts and their endoparasitoids, exhibit similar responses to thermal conditions. We reared two generations of the Melitaea cinxia butterfly and its specialised parasitoid wasp, Hyposoter horticola, at three temperatures in the laboratory (26°C, 28°C, and 31°C). We found that the two species harbour different bacterial communities as adults, with the parasitoid exhibiting higher bacterial richness than its host butterfly. When the parental generation of the butterfly was exposed to high temperatures, the F1 generation exhibited increased bacterial richness but a reduced diversity (Shannon index). The opposite effect was observed for its parasitoid, but only for the wasps infected with Wolbachia, which appears sensitive to thermal conditions. Collectively, these results highlight that the bacterial communities of insect hosts and their parasitoids are distinct units, differently susceptible to environmental thermal conditions, particularly to temperatures experienced at the parental generation.