Predator detection and a possible dispersal behavior of the invasive New Zealand mud snail, Potamopyrgus antipodarum (Gray, 1843)

Behavior can play a large role in invasion success. Of particular importance may be the ability of an invader to detect and respond to unfamiliar potential predators. We examined a behavior related to dispersal in populations of the New Zealand mud snail (Potamopyrgus antipodarum) in response to chemical cues from crayfish and piscine predators. Populations of the snail isolated from North America and its native New Zealand were used in two separate experiments. In both experiments, groups of snails were placed in water either with or without predator cues, and the number of snails found floating attached to the surface tension of the water after ten minutes was noted. In the first experiment, a crayfish odor cue was used (from Procambarus clarkii), and, in the second, two fish, blacknose dace (Rhinichthys atratulus), and separately zebrafish (Danio rerio), were used to provide the chemical cues. In both experiments there was significant variation among populations in the proportion of snails that exhibited the floating behavior, with native populations tending to exhibit less floating behavior. The snails generally increased floating behavior in response to both crayfish and blacknose dace but not to zebrafish. In addition, we found no differences between populations of snails in their response to predator cues. Surprisingly, we also found that there were differences in floating proportions between populations of the same invasive clonal genotypes. These results suggest this behavior, which may be related to dispersal within water bodies, may be important in partially explaining the invasion success of the most common invasive clones in North America.