PARENT SESSION
Oral Session #65: Evolutionary Ecology/ Population Genetics. Presiding: G. Gerrish.
Thursday, August 9, 2001. 8:00 AM to 12:00 PM. Hall of Ideas J.
Adaptive foraging under predation hazard: testing optimization theory with stream fish.
Skalski, Garrick1, Gilliam, James1, 1
ABSTRACT- Animals are known to balance the benefits of feeding (e.g., growth rate) versus the costs of mortality (e.g., predation rate) when making behavioral decisions. However, the quantitative manner by which animals may assess these components of fitness remains largely unknown. Using laboratory studies with stream fish populations we test several competing models that describe how animals may behave when faced with a growth-mortality tradeoff (i.e., a behavior that increases growth rate, g, also increases mortality rate, u). The models vary in terms of the form of the tradeoff (linear vs. nonlinear) and the optimization criterion (maximize g, minimize u, minimize u/g, and maximize tg-u; where t is a parameter involving reproductive value). Our results measuring the behavior of foraging minnows (bluehead chubs) under predation hazard (via green sunfish) can (i) identify the best model for this experimental system and (ii) provide an example of how to test among alternative theories.
KEY WORDS: optimization, fish, predator, experiment