The green peach aphid Myzus persicae (Hemiptera: Aphididae) relies heavily on its olfactory system to locate plant hosts, find mates, and avoid parasitoids or predators. The insect odorant receptors (ORs) have been proven to play a critical role in the perception of odorants from the environment. In the present study, 33 odorant receptor candidate genes including the Orco gene were identified from the antennal, head, legs and body transcriptomes of M. persicae. Phylogenetic analysis of ORs from seven different orders of insect species suggests that ORs from different insect species are highly divergent and most ORs from the same species formed monophyletic groups. In addition, the aphid ORs were clustered into six different sub-clades in the same clade. Furthermore, the genomic structure of the OR genes also tends to be consistent, suggesting that ORs from the family Aphididae have a relatively close evolutionary relationship. Reads per kilobase per million (RPKM) and tissue expression profiles analyses revealed that 27 out of the 33 MperORs were uniquely or primarily expressed in the antennae, indicating their putative roles in chemoreception. This work provides a foundation to further investigate the molecular and ecological functions of MperORs in the aphid–aphid, aphid–plant and aphid–natural enemy interactions.

The greater wax moth Galleria mellonella (Lepidoptera: Galleriinae) represents a ubiquitous apicultural pest that poses significant threats to global beekeeping industries. The larvae damage honeybee colonies by consuming wax combs and tunneling through brood frames, consequently destroying critical hive infrastructure including brood-rearing areas, honey storage cells, and pollen reserves. Larval feeding behavior is critically dependent on chemosensory input for host recognition and food selection. In this study, we conducted a transcriptome analysis of larval heads and bodies in G. mellonella. We identified a total of 25 chemosensory genes: 9 odorant binding proteins (OBPs), 1 chemosensory protein (CSP), 5 odorant receptors (ORs), 4 gustatory receptors (GRs), 4 ionotropic receptors (IRs) and 2 sensory neuron membrane proteins (SNMPs). TPM normalization was employed to assess differential expression patterns of chemosensory genes between heads and bodies. Nine putative chemosensory genes were detected as differentially expressed, suggesting their potential functional roles. Subsequently, we quantified expression dynamics via reverse transcription quantitative PCR in major chemosensory tissues (larval heads, adult male and female antennae), revealing adult antennal-biased expression for most chemosensory genes in G. mellonella. Notably, two novel candidates (GmelOBP22 and GmelSNMP3) exhibited particularly high expression in larval heads, suggesting their crucial functional roles in larval development and survival. These findings enhance our understanding of the chemosensory mechanisms in G. mellonella larvae and establish a critical foundation for future functional investigations into its olfactory mechanisms.

Apis cerana cerana is a key social insect, and its ability to recognize chemical signals is crucial for maintaining colony homeostasis and coordinating collective behaviors, such as foraging, nursing, and defense. The legs of insects play a significant role in gustatory perception and proximity olfactory perception. In this study, the leg sensilla of A. c. cerana were observed by scanning electron microscopy (SEM). Two types of sensilla were observed, including sensilla trichodea (Str I, Str II, Str III, Str IV, Str V, and Str VI) and sensilla chaetica (Sch I, Sch II, and Sch III). The two unique structures of the tibial spur (Tsp I, Tsp II) and antennal brush (Abr) are carefully observed. The electrophysiological responses of workers at different ages to diverse chemical compounds were measured via electrolegogram (ELG) recordings on their legs. The results showed that 1-day-old A. c. cerana was more sensitive to nonanal; 10-day-old and 25-day-old A. c. cerana were more sensitive to ocimene. The results of behavioral responses showed that nonanal and ocimene can significantly attract 10-day-old workers of A. c. cerana. This study establishes a foundation for further exploration of the mechanisms by which the legs of A. c. cerana facilitate colony-level communication through chemical signals. It also provides an important theoretical basis for understanding their social organization and information transmission.

Yellow mealworm (Tenebrio molitor) larvae can convert low-value organic residues into insect biomass, but their performance depends on substrate composition and feeding strategy. We evaluated vegetable wastes, okara–wheat–bran diets and kitchen waste–wheat–bran mixtures under a dynamic feeding regime. Ingredient and proximate compositions were determined, and larval growth, fresh-weight-based waste reduction (WR), bioconversion rate (BCR) and feed conversion efficiency (FCE), pupal output, nutritional composition and heavy metal contents were assessed. Among vegetable wastes, potato showed the highest numerical WR (95.18 ± 0.73%) and relatively high BCR and FCE, whereas pumpkin produced the most pupae (109.00 ± 8.62 per replicate). Cabbage showed reduced biomass conversion and pupal output. In the okara trial, 40% okara showed the highest numerical WR (75.88 ± 0.39%), 10% okara maximized FCE (15.83 ± 0.38%) and 20% okara produced the greatest pupal output. Principal component analysis (PCA) indicated treatment-specific conversion and developmental patterns, but was interpreted as an exploratory association analysis rather than a causal model. Kitchen waste mixtures increased the relative fat proportion and reduced the relative protein proportion of larvae; the 3:2 mixture increased crude fat to 37.90 ± 0.22% while retaining 57.39 ± 0.40% crude protein. Higher kitchen waste inclusion was associated with greater larval arsenic (As) content, reaching 0.803 ± 0.001 mg/kg in the 5:2 treatment. Substrate composition should therefore be optimized together with conversion efficiency, product quality and safety screening.