Homing behaviour of juvenile Australian raspy crickets (Orthoptera: Gryllacrididae)

摘要

Juvenile gryllacridid Orthoptera, known as raspy crickets, build nests or burrows as soon as they hatch. Both juveniles and adults are central place foragers that search for food at night and return to the same nest each morning. This study examines the homing abilities of juveniles of an undescribed species of gryllacridid from Western Australia. Juveniles were placed in a simple maze, which consisted of two chambers, one containing the nest and the other empty, linked by wide glass tubes to a central chamber containing food. The food was placed in this chamber with a consistent orientation relative to the exit tubes leading to the nest and empty chambers. Juveniles appeared to learn which chamber contained their nest and thereafter ignored the route towards the empty chamber. By exchanging the connecting glass tubes, it could be established that juvenile crickets were not using chemical trails to find their home. The positions of the empty and nest chambers with respect to the central chamber were exchanged and, in a separate manipulation, the spatial configuration of the food in the central chamber was also changed. Both manipulations resulted in a decrease in successful returns to the nest chamber, the former because the nest had been relocated, the latter presumably because the spatial arrangement of items within the food chamber now presented orientation cues, which led to the empty chamber. Furthermore, juveniles were able to estimate distance travelled, despite the absence of chemical or visual cues. Juvenile raspy crickets appear to be able to maintain nest fidelity from a very early age by using spatial landmarks and appear capable of measuring translational displacement intrinsically.