LATERALIZATION OF DETOUR BEHAVIOR IN POECILIID FISH - THE EFFECT OF SPECIES, GENDER AND SEXUAL MOTIVATION

We studied detour responses of two species of poeciliid fish (Gambusia hoolbroki and Girardinus falcatus) faced with a vertical-bar barrier, through which conspecifics of the same or different sex or a simulate d-predator (which induced detour behaviour for predator-inspection res ponses) were visible. Both species showed a consistent bias to turn le ftward when faced with the predator, and a consistent bias to turn rig htward when faced with an opaque barrier. Sexual stimuli (conspecifics of different sex) elicited a leftward bias in females that had been d eprived of the presence of males for 2 months, whilst no bias was appa rent in non-deprived females. Social stimuli (conspecifics of the same sex) elicited a consistent rightward bias in females but not in males in both species. Results suggest that males and females of both speci es show basically the same pattern of laterality and that sex differen ces, when present, can be accounted for in terms of differences in sex ual and/or social motivation. (C) 1998 Elsevier Science B.V. All right s reserved.