How multiple early experiences influence anti-predator behaviours in a cooperatively breeding cichlid. — ASN Events

How multiple early experiences influence anti-predator behaviours in a cooperatively breeding cichlid. (#137)

Stefan Fischer 1 , Evelyne Oberhummer , Barbara Taborsky 2
  1. University of Cambridge, Cambridge, United Kingdom
  2. Department of Behavioural Ecology, University of Bern, Bern, Switzerland

Predation is a strong force of natural selection and therefore the development of skills to successfully evade predator attacks are highly beneficial. However, acquiring these skills needs time and energy, which may constrain the resources available for acquiring other vital ecological or social skills. Therefore individuals should only strongly invest in the development of predator evasion skills if in the future environment high predation threat is expected. We predicted that individuals experiencing dangerous environments during critical periods early in life might invest more in the development of predator evasion skills than individuals experiencing a safe early environment. In a long-term developmental experiment with the cooperatively breeding cichlid Neolamprologus pulcher we manipulated the juvenile’s early perception of safety. In a 2x2 factorial design we varied the perceived predation risk as well as the social environment by raising juveniles with or without older group members. During the experience phase of 2 months we repeatedly measured the growth of all juveniles. To analyse their acquisition of predator evasion skills we performed two tests after the experience phase. The “predator discrimination test” tested the ability to discriminate between a dangerous predator and a harmless herbivore. The “egg predator test” tested for the ability to defend a brood produced by a dominant breeder pair when being a subordinate helper. During the experience phase test fish exposed to predators had a faster growth rate resulting in larger body size and thus reduced size-dependent predation risk. Interestingly, anti predator behaviours were interactively influenced by both early experiences when confronted with a dangerous predator but not when confronted with a herbivore or egg predator. We discuss how early experience might predispose individuals for their future life in a species where predation threat is a major force of the evolution of sociality.