Meeting Abstract
Physa snails change their shell morphology within and across generations based on the types of predators in their environment. It is unclear, however, the degree to which Physa morphological plasticity varies spatially and whether parental effects are generalized across predators. To address these questions, we used a predator-prey system consisting of Physa snails, and a fish predator, Lepomis macrochirus – the bluegill sunfish. F0 snails were collected from two sites: one containing bluegill sunfish and the other without., Eight maternal lines of snails (F1) were reared from each site. From each line, half the F1 snails were exposed to sunfish cues and the other half were exposed to control cues, i.e. water. After four weeks, we collected eggs for the F2 generation and reared them in the absence of cues. For each generation, at four weeks we measured snail crush resistance, size, and shape. In the F1 generation, snails from the site with fish were rounder and more crush resistant than snails from the site without fish, and, in contrast to control-reared snails, snails from both sites were more crush resistant and rounder when they were exposed to fish cues. Unexpectedly, however, we found no evidence that shell roundness was directly related to crush resistance. In the F2 snails, we again found that snails from the site with fish were more crush resistant than snails from the site without fish, but the offspring of snails exposed to fish cue were less crush resistant than those exposed to control cue. Overall, we conclude that parental effects in Physa snails differ depending on predator type. We also found evidence of site-specific shell morphology that may help the snails resist local suites of predators.
