Consistency among different tasks of left-right asymmetries in lines of fish originally selected for opposite direction of lateralization in a detour task

Lines of fish Girardinus falcatus preferentially turning rightward (RD) or leftward (LD) when facing a dummy predator visible behind a barrier have been obtained through selective breeding. To check whether lateralization was maintained in other behavioural responses, five different tests were carried out. They comprised measures of (1) turning direction in a T-maze, (2) proportion of clockwise and anticlockwise direction of rotation in a circular arena, (3) preferential eye use by females during shoaling behaviour (i.e., while looking at their own mirror image reflection), (4) preferential eye use by males during sexual behaviour (i.e., while turning around a barrier to join a group of females) and (5) preferential eye use by males during agonistic behaviour (i.e. while attacking a rival visible in a mirror). In all five tests the two selected lines showed strikingly opposite direction of lateralization. Results thus indicate that behavioural asymmetries in the detour test are predictive of lateralization in other types of behavioural tests. Moreover results show that RD and LD fish have a similar but specular pattern of subdivision of cognitive/behavioural functions, which is suggestive of a similarly specular brain organization.