Different social-learning strategies in wild and domesticated zebrafish, Danio rerio

Social learning probably functions as a mechanism to acquire public information about food, predators and conspecifics, without paying the costs required for individual learning. Social learning should be strategic rather than indiscriminate, and although it is often suggested that animals should show conformity (‘copy the majority strategy’), there are surprisingly few tests of this idea. Our goals were to test experimentally whether social learning plays a role in boldness behaviour of wild and domesticated zebrafish, and to investigate whether they utilize similar social-learning strategies and conformity in their boldness behaviour. We tested whether timid wild-derived zebrafish become bolder, and more likely to approach a moving stimulus, after interacting socially with bolder domesticated fish (and vice versa). We found that wild zebrafish exposed to domesticated fish were bolder than controls, whereas domesticated fish exposed to the more timid, wild zebrafish did not differ in their boldness score compared to controls. The changes in the behaviour of wild fish persisted after the nonfocal groups were removed; however, we found no evidence for conformity. Our findings indicate that zebrafish use social learning for assessing risk and adapt their social-learning strategies to the costs of a perceived risk. Future studies should be able to utilize this model species to incorporate genetic and genomic tools to study the development and evolution of social learning.