Scanning Electron Microscopy of the Antennal Sensilla and Their Secretion Analysis in Adults of Aromia bungii (Faldermann, 1835) (Coleoptera, Cerambycidae)

Background: It has been proved that chemical signals play an important role in mating location and reproductive behavior in cerambycids; moreover, they rely on contact chemoreception for mate recognition. Methods: Adult antennae of Aromia bungii were observed using scanning electron microscopy and adult antennal secretions were collected and analyzed with gas chromatography-mass spectrometry. Results: Twelve different types of sensilla were morphologically described on the antennae of A. bungii. At least six mechanoreceptors—one gustative, one putative chemo- or thermoreceptor, and three multiporous olfactory receptors—are present on the antennae of both sexes while a receptor-type of unclear function is limited to males. Secretions associated with sensilla basiconica were observed for the first time in a cerambycid species. Conclusions: Sensilla basiconica should play a role in odor perception detecting host tree volatiles and/or pheromones. Sensilla basiconica type 1 and 2 produce a viscous material accumulating on the antennal surface. Chemical analysis of adult antennal secretions highlighted marked differences between sexes. Some of the identified compounds have been previously reported as contact pheromone components of other cerambycid species. Our observations strongly suggest sensilla basiconica as the production sites of compounds involved in mate recognition.