Background risk during development and early life does not affect later activity and risk-taking across genetically distinct lineages of the mangrove rivulus
Description
Detecting and reacting appropriately to predation risk is crucial. Early exposure to cues associated with a high-risk environment can signal the background predation risk and if these cues alter development, they might give individuals a head-start in preparing for a dangerous environment later on. Here we examined how early cues of predation risk (i.e. embryo alarm cues) experienced either as embryos or as newly hatched fry affect response to a novel environment and a stressful disturbance in the self-fertilizing hermaphroditic mangrove rivulus (Kryptolebias marmoratus). Due to many generations of selfing, mangrove rivulus produce genetically identical offspring resulting in distinct genetic lineages, thus we could also examine whether genotypes vary in their developmental plasticity in response to risk. Although all individuals decreased their activity and risk-taking in response to a stressful disturbance, we found that early exposure to alarm cues, whether as an embryo or early hatched fry, did not affect this response. Furthermore, genotypes did not differ in their sensitivity to the early risk cues, although genetic lineages differed in their average behavior. Our results suggest that mangrove rivulus do not use early background risk to shape their behavior later on and that this insensitivity is consistent across distinct genetic lineages. It is possible that alarm cues experienced as embryos and/or young fry are not informative of future predation risk in the dynamic mangrove swamps in which these fish reside and thus are not used to shape future responses.