Relationship between the movements of the mouthparts of the bamboo powder-post beetle Dinoderus minutus and the generation of acoustic emission

In order to apply acoustic emission (AE) monitoring to the non-destructive and continuous analysis of the feeding biology of the bamboo powder-post beetle Dinoderus minutus inside bamboo culms, it is essential to clarify the relationship between their feeding activity and AE generation. In this study, the behavior of the larva and adult of D. minutus in a madake (Phyllostachys bambusoides) specimen was directly observed by a microscope, while AE measurement of the specimen attached to an AE sensor (150 kHz resonant frequency) was conducted simultaneously. The mandibles of the larva or the adult exhibited chewing movements when it was in feeding activity. AE hits were detected as the larva or adult chewed the specimen with its mandibles. Under the measurement conditions employed, chewing movements of the mandibles that produced AE hits accounted for 26-42 % of the total chewing movements for larvae, and 27-43 % for adults. On the other hand, when the larva or adult was not chewing the specimen, almost no AE hits were detected. Therefore, the generation of AE corresponded to the chewing movements of the mandibles of D. minutus.