Background risk and recent experience influences retention of neophobic responses to predators

摘要

Recent studies have shown that prey living under conditions of elevated predation risk respond very differently to novel predators than prey living under low-risk conditions, by displaying generalized avoidance patterns to novel stimuli. This phenotypic plasticity in neophobic responses provides prey with the means to respond flexibly to uncertain risks, but we know almost nothing about how long neophobic responses are maintained. Using extinction testing, we demonstrate that neophobic responses of guppies (Poecilia reticulata) to a novel odour waned relatively quickly over five consecutive exposures, but the waning of responses to one stimulus does not affect neophobic responses to other novel odours. In a subsequent experiment, we demonstrate that learned responses to predator cues in fish from high- and low-risk populations both waned over time, but fish from the high-risk population retained the response longer than those from the low-risk population. Background levels of predation risk appear to be crucial factors in driving differences in retention of risk-related information.