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.