Responses of prey from habitats with different predator regimes:: Local adaptation and heritability

We aimed to assess whether prey organisms with limited large-scale dispersal abilities are locally adapted to prevailing predator regimes by studying how chemical cues from predatory fish affected the behavior of Gammarus pulex (Amphipoda) from ponds with and without fish. We also examined, in the laboratory, the F1 generation from each pond by incubating them with or without cues from predatory fish. The potential benefits of a behavioral avoidance response were also assessed in an experiment in which G. pulex from the different ponds and incubations were exposed to fish predation. G. pulex from fish ponds increased their refuge use when exposed to fish cues, whereas populations from fishless ponds reduced their refuge use. The F1 generation responded similarly to their parents. Only the F1 generation from fish pond populations responded with more pronounced antipredatory behavior when raised in fish water. Moreover, both the original and the F1 generation of fish pond G. pulex survived longer when exposed to fish predation than those from fishless ponds, independent of whether they were raised in fish water or not (F1). Our results suggest that the behavioral response to predator cues in G. pulex is an inherited trait, i.e., a local adaptation to prevailing predator regimes.