Nest utilisation and recognition by juvenile gryllacridids (Orthoptera : Gryllacrididae)

Abstract

Gryllacridid ensiferans (Orthoptera : Gryllacrididae) appear to display a degree of nest-site fidelity comparable to that of most social insects. The nesting behaviour of juvenile gryllacridids was studied to determine when nests were first built and whether juveniles were able to subsequently recognise their own nests. Additionally, the hypothesis that juvenile gryllacridids could orient to their nest over distance by chemical means was examined via a directional choice experiment within a simple olfactometer. Juveniles of a known ‘nest-building’ gryllacridid constructed nests within days of hatching, reflecting current ideas that nesting is an integral component of gryllacridid biology. Such nests were occupied preferentially over extended periods. Furthermore, individual juveniles were capable of recognising their own nest from that of their conspecifics. Such a result supports recent findings of an individual/nest-specific chemical odour amongst adult gryllacridids. However, the results provide no evidence that juvenile gryllacridids are able to detect the presence of their own nest over any substantial distance and some mechanism other than chemically based orientation is necessary to explain the apparent homing ability of these orthopterans.