Path selection by the termite Reticulitermes speratus kyushuensis (Isoptera: Rhinotermitidae) at a bifurcation node of Y-shaped tunnel

Subterranean termites excavate complicated tunnel networks for foraging below the ground. During foraging activity, termites often encounter many bifurcation nodes generated by the tunnel branching or the tunnel tunnel interaction. Path selection by termites at the node is likely to affect the foraging efficiency because depending on their selection, the traveling distance from food resources to the nest can vary significantly. To understand the selection mechanism, we artificially constructed Y-shaped tunnels in small arenas and observed the termite behavior at the bifurcation node (i.e. the intersection of the tunnel). At the bifurcation node, the right side tunnel forms 45 with respect to the straight tunnel that a termite advances, while the left side tunnel forms the angle of theta (= 5 degrees, 15 degrees, 30 degrees, and 45 degrees). The experimental results showed that the path selection strongly depends on which termite's antenna touching is first made on the tunnel wall at the bifurcation node. The left (or right) antenna touching tended to cause the right (or left) tunnel selection. As the value of theta increased, the tendency for the left selection ratio decreased. The bias of the advancing termites towards the left (or right) enhanced the tendency of the selection of the left (or right) tunnel but did not affect the spent time of the termites to pass through the node. The results were understood by the location relationship between the advancing termites and the tunnel wall. We briefly discussed the meaning of our finding in relation to the foraging efficiency. (C) 2016 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society. Published by Elsevier B.V. All rights reserved.