Exploring antennal asymmetry in electrophysiological response, behavior, and olfactory gene expression in the...

Left-right asymmetries in brain features and behavior have long been considered unique to humans. However, they are now also recognized in vertebrates and invertebrates and exhibit similar structural lateralization across different species. For instance, the olfactory behavior and brain asymmetry of eusocial insects are evident at the population level. Certain solitary insects also exhibit behavioral asymmetry at the population level. This study examined the electroantennogram (EAG) responses, behavioral responses, and gene expression of the right and left antennae in adult diamondback moth (DBM), Plutella xylostella (lepidoptera: plutellidae). The results revealed that among the detected genes (GOBP1, GOBP2, PBP, PBP1, and ORCO), only the GOBP1 gene showed expression variance between the left and right antennae of female DBM. Also, the expressions of GOBP1 and GOBP2 in the antennae of female moths were significantly higher than that in male DBM. For male DBM, EAG responses of the left antenna were higher at differentconcentrations of Z-3-hexenol, Z-3-hexenyl acetate and allyl isothiocyanate compared to the right antenna. Marked differences were found in EAG responses between the left and right antennae of male DBM at 0.15 μg•μL^-1 allyl isothiocyanate. For female DBM, EAG responses of the right antenna were higher at differentconcentrations of Z-3-hexenyl acetate and allyl isothiocyanate compared to the left antenna, but there was no statistical difference. In an olfactometer bioassay, the choice rates of male DBMs with intact left antennae were significantly higher than that of the control liquid paraffin at 1.0 μg•μL^-1. Also, the choice rates of female DBM with left or right antennae to the three tested plant volatiles at 0.15 and 1.0 μg•μL^-1 concentrations were significantly higher than those in liquid paraffin. Moreover, the relative choice rates of the right antennae were slightly higher than those of the left antennae in female DBM, but the results were reversed in male DBM. This study contributes to the understanding of behavioral asymmetry of the left and right antennae of DBM and provides a reference for the lateralization of olfactory behavior in other lepidoptera insects.