X-ray computer tomography (CT) was applied to observe the movement of the larvae of the wood-boring beetles Lyctus brunneus, Lyctus africanus, and Heterobostrychus aequalis inside the infested wood specimens. The larvae bred with artificial diet were inserted into the hole of wood specimens of rubber wood Hevea spp. or Japanese oak Quercus crispula. The wood specimens with larvae were scanned using the microfocus X-ray CT system every 3 to 7 days. In the CT images, with the voxel size of 61.9 μm, the figures of the larvae and other stages of the beetles were clearly visible and were distinguished from wood, tunnels, and frass. It was also possible to trace the movement of larvae, mostly along the fiber direction. However, all of the larvae of H. aequalis had hardly bored and had pupated or died near the inner surface of the specimen, in this study. The CT images were also used to evaluate the amount of wood bored by a larva. The larva was traced until pupation and the time courses of tunnel length and volume were estimated by measuring the changes in the length and volume of the tunnel in pixels. Thus mean tunnel length and volume of larvae of L. brunneus or L. africanus are estimated to by 1.89 mm and 6.64 mm3, or 1.38 mm and 3.12 mm3 per day, respectively.

Download document (276 kb)
free for the members of IRG. Available if purchased.

Purchase this document