WATKINS, T.B.*; PASKIN, G.; VRASPIR, J.; Macalester College: Six Degrees of Separation: The Effects of Egg and Larval Temperature on Swimming Speed of Wood Frog Tadpoles

Female wood frogs (Rana sylvatica) lay their eggs in the same location within a pond and thereby create clumps that may contain hundreds of egg masses. The middle of a clump is warmer than the periphery, by as much as 7 �C. Differences in egg incubation temperature of this magnitude are known to affect several physiological and behavioral traits of reptiles, including locomotor performance. Little is known about such effects in anurans, but the one published study of frogs (Parichy & Kaplan 1995) indicates that cooler egg incubation can result in faster hatchlings. We sought to determine whether egg incubation temperature affects swimming speed in wood frog tadpoles, and if the temperatures that tadpoles subsequently experience during development modify such effects. We reared wood frog eggs at 15 and 21�C until they hatched, and then reared tadpoles from both egg treatment groups at 15, 18, and 21�C until they reached a late larval stage. Burst swimming speed over a range of test temperatures was determined from video records (30 frames/s). We will discuss our results in the context of potential trade-offs between thermal effects on burst speed and on growth and development.