Ontogeny and personality affect inhibitory control in guppies, Poecilia reticulata

In mammals and birds, interindividual variability in inhibitory control is often explained by developmental changes and personality. Teleost fish exhibit one of the highest levels of intraspecific variability in inhibitory control described in vertebrates, but the underlying causes have not been fully described. We investigated the effects of development and personality on inhibitory control of a teleost fish, the guppy. In experiment 1, we compared the performance of 10-, 20-, 40- and 90-day-old guppies in the cylinder task, which requires subjects to inhibit the tendency to swim towards a food reward. We found that guppies of all ages tested were capable of executing the motor inhibition required by the task. However, there was a U-shaped effect of age on performance: 10- and 90-day-old guppies had lower inhibitory control compared to 20- and 40-day-old guppies. In experiment 2, we correlated guppies’ inhibitory control performance with three tests aimed to assess different personality trials: boldness (scototaxis test), exploration (open-field test) and sociability (mirror test). We found a significant covariation only for the open-field test, which might indicate that more explorative guppies exhibited greater inhibitory control. Overall, this study suggests that ontogeny and personality may have a role in determining interindividual differences in a teleost fish similar to that described in mammals and birds.