Continuous nondestructive monitoring of larval feeding activity and development of the bamboo powderpost beetle Dinoderus minutus using acoustic emission

Abstract

The life history and feeding biology of the bamboo powderpost beetle Dinoderus minutus remain poorly understood because the beetles' oviposition, development, and feeding take place inside bamboo culms. In this study, acoustic emission (AE) monitoring was applied for continuous nondestructive analysis of larval feeding activity and development from the first instar to adult eclosion. Newly hatched larvae were inoculated individually into pieces of madake (Phyllostachys bambusoides) culms. AE hits were recorded using single AE sensors fixed onto the bamboo pieces. Generation of AE hits indicated that larval feeding activity had begun after inoculation. Based on the time course of the hourly AE hit rate, the larvae were feeding constantly during each instar, and feeding activity only ceased during periods of ecdysis and pupation. Half of the individuals examined underwent seven instars and the other half underwent eight instars. The time course of AE hit rate per 5 min exhibited periodic cycles, where continuous meals were separated by inactive phases of ca. 5 min, with an average dominant period of each instar ranging between 0.76 and 2.19 h. After correcting the AE data based on distance attenuation of AE waves, the tendency that AE amplitude increased as the larvae developed through ecdysis events became more apparent. AE monitoring continued after adult eclosion, and the feeding activity of the newly emerged adults continued almost ceaselessly during the Reifungsfrass period.

Nondestructive evaluation of oviposition behavior of the bamboo powderpost beetle, Dinoderus minutus, using X-ray computed tomography and acoustic emission

“…As will be shown later, the tunneling activity of mated males exhibited statistically significant circadian rhythms. Furthermore, our previous study showed that, in the Reifungsfrass period (the period of feeding by newly eclosed adults), the feeding activity continued almost ceaselessly, with no regular pauses, for approximately 10 days [7]. These findings suggested that the pattern in which short pauses in tunneling activity occur at certain intervals longer than 1 day is characteristic of the oviposition period of females.…”

“…AE signals detected by the sensors were filtered using 100-400 kHz bandpass filter and amplified by 40 dB in the preamplifier and by 20 dB in the system amplifier. The signals were then discriminated at a threshold of 100 dB, a level that would not be sensitive to low-amplitude signals generated by early instar larvae [7], and a signal that exceeded this threshold was recorded as an "AE hit".…”

“…We previously demonstrated that X-ray computed tomography (CT) [4,5] and acoustic emission (AE) monitoring [6,7] were effective techniques for nondestructively analyzing the feeding and development of D. minutus. In this study, we applied these two techniques to analyze the oviposition behavior; X-ray CT was used to observe and quantify the extension of oviposition tunnels and the number of eggs laid by females, and AE monitoring was used to continuously record and analyze the tunneling activity of females after mating.…”

Behavioral characterization and alternative control methods of the Bamboo borer [Dinoderus minutus Fabricius (Coleoptera: Bostrichidae)]

“…This is due to the structural anatomical constitution of the bamboo stems (culms), which presents parenchyma cells rich in starch reserves, which according to some authors is the main attraction to the bamboo borer [Dinoderus minutus Fabricius, 1775 (Coleoptera: Bostrichidae)] after harvesting (Abood and Norhisham, 2013). Due to its vulnerability to the attack of this insect, the bamboo wood may be reduced to dust in a short time, causing serious economic losses and making its use impracticable (Watanabe et al, 2018).…”