Meeting Abstract
We have recently found that physid snails exposed to predator cues produce offspring with increased crush resistance, a potential example of an anticipatory maternal effect. However, predator cues also cause Physa snails to reduce foraging and spend more time engaged in anti-predator behavior. We tested whether observed maternal effects were directly induced by predator cues or were a byproduct of reduced foraging by the parents. We exposed F1 snails to early life predator treatments and food restriction treatments in a full factorial design. Predator treatments were either non-lethal predator cues from the southern plains crayfish (P) or control cues (C) consisting of dechlorinated water. Food treatments were a full food (F) treatment (individuals were fed ~5mg of algae wafer twice a week) or a food restriction (S) treatment (individuals were fed ~5mg of algae wafer once a week). The treatments were applied for four weeks, after which all individuals were switched to the CF condition. After eight weeks, we mated F1 snails of the same treatment and collected the eggs to produce an F2 generation. We raised F2 snails from all treatments in a common garden environment with no cues, and ad-libitum food. For the F1 and F2 snails, we measured the shape, size, and crush resistance of their shells. In the F1 snails we found that predator cues changed shell shape regardless of food restriction, and food restriction reduced crush resistance regardless of predator cues. In the F2 snails, we found that parental predator and food treatments had an interactive effect with food restriction causing an increase in crush resistance if the parents were not exposed to predators and no change in crush resistance if the parents were exposed to predators. We provide informational and resource based explanations for our results.
