The precision of auditory lateralization in the cricket, Gryllus bimaculatus

ABSTRACT. The precision of auditory lateralization was determined behaviourally for the cricket, Gryllus bimaculatus L. A forced-choice Y-maze test was devised in which the cricket, on entering the test arena, could not — in contrast to free phonotactic approaches — change its walking direction until after it had passed through a narrow wire-mesh tunnel. For a sound frequency of 4.7 kHz, matching the species' calling frequency, the minimum audible angle for correct side discrimination was 15°. For stimulus angles smaller than 15° from the longitudinal body axis, the crickets walked randomly to either side; stimulus angles greater than 25° resulted in all crickets turning correctly. These data reveal a sharply tuned lateral sensitivity for the auditory pathway of crickets, with an optimum at the species' calling frequency of 4.7 kHz (when compared with 3.5 and 6.0 kHz). The results for the forced-choice test are compared with the walking pattern during free phonotactic approaches, in order to determine the possible strategy underlying the acoustic orientation behaviour of the cricket.