Mate location in the deathwatch beetle, Xestobium rufovillosum De Geer (Anobiidae): Orientation to substrate vibrations

Abstract

Deathwatch beetles produce taps, by drumming the head on the substrate, which enable males to locate females. The orientation mechanism used by males was examined experimentally using a mechanical tapper to simulate female replies. When searching for a female, males moved short distances before stopping to tap, tapped only once or twice if they got a reply, and turned frequently. In the absence of replies males moved longer distances before stopping to tap, and turned less. Males did not use tropotaxis during mate location, but exhibited a weak klinokinesis. Their turn angles tended to be larger when a long way from the female, and following a movement away from the female, so that they turned back towards it. However, the mechanism is not efficient as many males studied failed to locate the female. Mechanisms for the evolution of this unusual mate-locating system are discussed in the context of the recently available artificial habitat occupied by deathwatch beetles.