Population lateralisation and social behaviour: A study with 16 species of fish

Abstract

We investigated turning responses in 16 species of fish faced with a vertical-bar barrier through which a learned dummy predator was visible. Ten of these species showed a consistent lateral bias to turn preferentially to the right or to the left. Species belonging to the same family showed similar directions of lateral biases. We performed an independent test of shoaling tendency and found that all gregarious species showed population lateralisation, whereas only 40% of the non-gregarious species did so. The results provide some support to the Rogers (1989) hypothesis that population lateralisation might have been developed in relation to the need to maintain coordination among individuals in behaviours associated with social life.

Parallel Emergence of True Handedness in the Evolution of Marsupials and Placentals

“…Thus, we hypothesize that the specializations of forelimb functions in red-necked wallabies have been shaped under the pressure of ecological factors. This interpretation is consistent with the general evidence for high evolutionary plasticity in motor and sensory lateralization (e.g., [35,[44][45][46][47]). …”

Laterality as an indicator of emotional stress in ewes and lambs during a separation test

“…Thus, motor laterality can be the result of a selective pressure to align the direction of the asymmetries in most individuals of a social and gregarious population (Vallortigara and Rogers 2005). For example, this coordination would be very important under predation and serve to keep the flock closer together as a defensive tactic, as it has been suggested for other species (Bisazza et al 2000). Rogers and Andrew (2002) speculated on an association between left/right bias at the population level based on the valence hypothesis mentioned at the beginning: species for which survival depends on withdrawal and being more fearful of new environments should have the right hemisphere dominant over emotional and behavioural processing, as opposed to species that are adapted to a high level of exploration to survive.…”

Lateralization of Cognitive Functions in Fish

“…Recent studies have confirmed that the eye used to look at the dummy predator in the detour test is the same as that used when viewing a real predator (Brown et al 2004(Brown et al , 2007aBisazza et al 2007). Bisazza et al (2000a) compared 16 species from different fish families in the detour test. Fishes of all 16 species were trained to escape from the same stimulus (a dip net provided with two eyes) that mimicked a predator and was used as the target stimulus in the detour test.…”

“…However, empirical evidence in support of this hypothesis is equivocal. Bisazza et al (2000a) examined 16 species of fishes and found evidence that population biases were more frequent in species with a strong shoaling tendency than in solitary ones, but this finding requires confirmation using a larger sample size and correcting for phylogeny. Conversely, found no difference in schooling efficiency when comparing groups composed of female topminnow of mixed laterality (LD and RD) and groups of females with the same laterality.…”