Nondestructive evaluation of egg-to-adult development and feeding behavior of the bamboo powderpost beetle Dinoderus minutus using X-ray computed tomography

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, X-ray computed tomography (CT) was employed to nondestructively quantify the progression of larval body size and tunnel size from the first instar to pupation. Eggs of D. minutus laid between laminates of nutrient-containing filter paper were easily collected. The newly hatched larvae were inoculated singly into pieces of internodes of madake (Phyllostachys bambusoides). The pieces were scanned using a microfocus X-ray CT system every 3-5 days to visualize the beetles' bodies and tunnels with resolutions of 18-60 lm/voxel. CT scans were continued after adult eclosion to analyze pre-mating adult feeding. The collected eggs were 0.84 ± 0.06 mm (mean ± SD) in length and the egg duration lasted 5.0 ± 0.8 days. Based on CT images, the larvae grew to 3.53 ± 0.23 mm in body length and turned into pupae of 3.42 ± 0.09 mm. The larvae bored tunnels with a length of 80.2 ± 4.8 mm and a volume of 68.0 ± 7.0 mm 3 over the larval period of 61 ± 11 days. Newly emerged adults remained in the bamboo pieces to feed before making exit holes in 8 ± 1 days after adult eclosion. During this period, they bored tunnels at rates of 2.64 ± 0.58 mm/day in length and 4.87 ± 1.10 mm 3 /day in volume.

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

“…Bamboo pieces, 100 [longitudinal (L)] × 20 [tangential (T)] mm, were prepared from air-dry internodes of madake (Phyllostachys bambusoides) culms, 6-7 mm [radial (R)] thick, felled in June 2014 in Kyoto Prefecture, Japan. Eggs of laboratory strains of D. minutus reared on madake culms were collected using laminates of nutrient-containing filter paper, as described previously [10], and newly hatched first instar larvae were collected randomly for inoculation into the bamboo pieces. A hole with a depth of 5 mm was drilled longitudinally on one end surface of each bamboo piece with a 2.5-mm drill bit and the hole was extended by 5 mm with a push pin.…”

“…Scans were performed daily when pupation and Illustration of the bamboo piece with a first instar larva inoculated in the hole and an AE sensor glued onto the upper end surface adult eclosion approached. Methods of CT scanning and measurement of larval tunnel length and volume were based on our previous report [10]. The CT data of individuals AX1 and AX2 have been published in this report [10].…”

“…Methods of CT scanning and measurement of larval tunnel length and volume were based on our previous report [10]. The CT data of individuals AX1 and AX2 have been published in this report [10]. The eight individuals that were not used for CT scanning are referred to as A1-A8.…”

“…We reported previously that the developmental stages of D. minutus were clearly distinguishable in images obtained by X-ray computed tomography (CT) and their bamboo consumption was assessed quantitatively [9]. We then traced the egg-to-adult development and tunneling process and quantified the growing body size and extending tunnel size in the entire larval period, with the aid of nutrient-containing filter paper for egg collecting [10]. On the other hand, because of the inability to conduct continuous monitoring, uncertainty remained regarding the activity of larvae between the CT scans.…”

Non‐destructive observation of the mycangia of Euwallacea interjectus (Blandford) (Coleoptera: Curculionidae: Scolytinae) using X‐ray computed tomography

“…Within the last 10 years, a new technology, X‐ray computed microtomography (micro‐CT) has recently been applied to research concerning the microstructure of a wide array of insects (Alba‐Tercedor & Caparrós ; Iwan et al ; Dougherty & Simmons ; Watanabe et al ). A series of non‐invasive views through the sample are reconstructed mathematically into transverse 2‐D cross‐sections, and with dedicated software protocols, detailed 3‐D images are produced (Landis & Keane ).…”