The aphid Myzus persicae is an important agricultural pest relying on olfactory cues to find food and escape from predators. The considerable difficulty of anatomical manipulation and other related technical challenges may underlie the absence of studies systematically mapping the central projections of antennal sensory neurons in its central nervous system. We used mass stain, immunohistochemistry, laser scanning confocal microscope and three-dimensional reconstruction techniques to trace the central projections of sensory neurons from the antennae. The ipsilateral antennal nerve targets mainly the antennal lobe, the antennal mechanosensory and motor center, and most neuromeres of the ventral nerve cord. There are also several axons that project to other regions, like the contralateral antennal lobe, the contralateral antennal nerve, the ipsilateral calyx and some region of the protocerebrum. The numerous neuropils innervated by axons from the antenna indicate the multiple roles that this sensory organ serves in insect behavior, and the results which provide information about the basic anatomical arrangement of the olfactory nervous system in aphid M. persicae may provide some basic knowledge for the further investigations of the aphid.

Trehalose serves as both a hemolymph sugar and stress protectant, playing pivotal roles in insect energy metabolism, development, and stress adaptation. Its transmembrane transport is mediated by trehalose transporters (TRETs). Baryscapus dioryctriae, a parasitoid wasp targeting the red pine shoot borer, shows great potential for biocontrol. Prior genomic assemblies indicated prominent expansion of the Tret gene family in this wasp, yet systematic characterization of these genes has not been reported. Here, leveraging a chromosome-level genome, we identified 94 BdioTrets. Phylogenetic analysis placed them closest to Phytomastichus coffea Trets (maximum identity: 88.15%). Most members conserved the GRR/K motif, N-glycosylation sites, and key residues in TM7/TM10. Fourteen candidate genes were further verified via reverse transcription quantitative PCR (RT-qPCR), and Pearson correlation analysis showed that 11 of the 14 candidate genes have strong and significant positive correlations for their tissue expression profiles (r > 0.7, p < 0.05), indicating consistent expression trends between RNA-seq and RT-qPCR. These genes exhibited stage-specific expression: BdioTret9 peaked in eggs; BdioTret3,5 and 67 in larvae; BdioTret25 in prepupae; and BdioTret6 in pupae, while eight others dominated in adults. Tissue-specific profiling revealed pronounced sexual dimorphism in antennal expression and distinct localization in the abdomen (sex-biased) and legs. Our findings demonstrate that the large-scale BdioTrets expansion, coupled with precise spatiotemporal regulation, establishes a flexible energy network supporting the parasitic lifecycle. These results lay a fundamental framework for future functional investigations of TRETs in hymenopteran parasitoids.

Beta-cypermethrin is widely applied in Korean pine (Pinus koraiensis Siebold & Zucc.) seed orchards to control cone- and seed-infesting moths (e.g., Dioryctria spp.), yet its Wsublethal risks to non-target beneficial arthropods remain insufficiently characterized. Here, we systematically evaluated the ecological and physiological consequences of beta-cypermethrin exposure on the key parasitoid wasp Baryscapus dioryctriae Yang & Song, an important biological control agent in P. koraiensis forests. Adult wasps were exposed to LC₃₀ and LC₅₀ residue concentrations, and sublethal effects were quantified across reproductive, developmental, and biochemical endpoints over two generations. Sublethal exposure resulted in significant reductions in parasitism rates and offspring emergence, as well as altered developmental durations and adult longevity in both F₀ and F₁ generations. Enzymatic assays revealed time-dependent activation of detoxification enzymes (GST, CarE, AChE) alongside suppression of antioxidant defenses (CAT strongly; SOD early with partial recovery; POD biphasic), consistent with a sustained oxidative-stress burden. LC-MS/MS residue analysis further confirmed the accumulation and slow clearance of both beta-cypermethrin and its metabolite 3-phenoxybenzoic acid (PBA) within parasitoid tissues. These findings collectively demonstrate that even non-lethal concentrations of beta-cypermethrin can undermine the ecological fitness and persistence of B. dioryctriae, posing a tangible threat to the sustainability of biological control services. To safeguard beneficial parasitoids, integrated pest management strategies must incorporate selective insecticide use and exposure mitigation, especially in forest habitats where biological control is indispensable.