Does water velocity influence optimal escape behaviors in stream insects?
Author InfoTrent M. Hoover John S. Richardson Abstract Optimal escape theory can successfully explain variation in the distance to an approaching predator at which prey initiate flight (the flight initiation distance, FID). However, for animals without access to refuges, optimal escape theory may also explain variation in the distance that prey flee (the retreat distance, RD). In benthic stream habitats, both the risk of predation and the costs of escape may be mediated by water velocity; optimal escape theory then predicts that FID and RD of slow-current insects should vary little with increasing current velocity, whereas the FID and RD of fast-current insects should decrease. To test this prediction, a simulated predator (SP) was used to initiate escape responses in 3 mayflies found in different habitats–Ameletus (slow pools), Baetis (fast riffles), and Epeorus (very fast cascades)–across a range of water velocities. Unexpectedly, the FID of all 3 prey did not vary with water veloc
