Change in Tunnel Heading in the Formosan Subterranean Termite (Isoptera: Rhinotermitidae) in Response to Movement Through Opened Space

Abstract

Abstract Subterranean termites excavate tunnel patterns that radiate outward from a point of origin along vectors generated by path integration. Upon encountering open space, the tunnel heads away from the new site. In this study we forced termite excavators to travel from an introduction chamber through a tube with a 90° bend before entering a sand-filled arena, an opened chamber with perpendicular openings that forced a 90° turn before access to the arena, or an open chamber with an odor trail left by previous termites traveling through the opened chamber connecting the perpendicular openings. When forced to move through an opened chamber with no odor trail, the termites tunnelled away from the second chamber, not the introduction chamber. In contrast, when a path is either constrained inside a tube or demarcated by odor trail the path was more likely to head away from the first chamber, suggesting that they are not responding to a cue derived from an intrinsic value of open space. The discontinuation of their perceived path as they traveled through the open space seems to have caused an updating of the path integrator. The location of the deposition of excavated sand from the arena within the tube and chamber system varied, with sand found only in the second chamber when the path was broken. The cues that cause an updating of the path integrator also may stimulate sand deposition.