Predator-prey space use as the emergent outcome of a behavioral response race: Effects of prey activity

How predators and prey distribute themselves across space can have large population and community level consequences by affecting the frequency and potential strength of interactions between and within trophic levels.  The general pattern that emerges from numerous studies is for predators to seek areas with higher prey densities and for prey to avoid areas with higher predation risk.  Almost all of these studies, however, have focused either on predators or prey and have spatially fixed the distribution of the other species. In nature, many systems feature mobile predators and prey that freely interact. Spatial patterns thus reflect a space race involving conflicting predator and prey responses.  We examined the behavior and space use of Pacific tree frog tadpoles, Pseudacris regilla, and Western toad tadpoles, Bufo boreas, as prey and dragonfly nymphs, Aeshna walkeri, as predators in a two patch arena that differed in basal resource level.  The prey species were chosen based on differences in activity with the B. boreas tadpole having a higher activity.  With this difference how does the race change?  Preliminary results show both species of prey significantly shifted their space use in response to the presence of the predators while the predators did not significantly change their distribution with or without prey.  Interestingly the two species of tadpoles showed a significant survival difference with the P. regilla individuals surviving better even though their distributions and most spatial coincidence measures with predators were similar. Results support some predictions of extant game models, but contradict others.