Presence of parents during early rearing affects offspring responses towards predators

Abstract

Social learning about predation threat during early ontogeny can be beneficial in developing appropriate antipredator behaviours. While such learning can be achieved through direct interactions between offspring and parents, it is unknown whether young animals can also learn appropriate responses towards different heterospecifics posing different levels of threat through inadvertent information obtained from witnessing parental interactions with these heterospecifics. In this study, we split sibling groups of the cooperatively breeding cichlid Neolamprologus pulcher and raised them with or without parents. Both rearing groups repeatedly received visual and olfactory cues from four types of fish (predators, egg predators, herbivores and conspecifics) during a 4-week experience phase. After a ‘neutral phase’ of 4 months under identical conditions and without further fish stimuli, individuals from both rearing conditions were tested for their response towards the same four stimulus species. Unlike those reared with parents, the fish reared without parents spent significantly more time in safety and were more vigilant towards the predator, whereas responses to the other three species did not differ. As during the experience phase parental responses towards the stimulus fish were unexpectedly low and indiscriminate, our results suggest that young N.\xa0pulcher reverse their innate fear of predators when observing parents being unresponsive to a threat (‘observational conditioning’). We suggest that learned reduction of fear can be a potent mechanism to prevent responding to false alarms and mitigate potentially harmful effects of chronically elevated predation stress.