Behavioral temperature selection in Rana pipiens: do they select temperatures where they perform best?

Abstract

Some ectotherms, such as leopard frogs (Rana pipiens) rely to a great extent on behavioral means to regulate their temperature. Temperatures selected may be influenced by performance levels -- that is leopard frogs may select temperatures where they perform best. This is what was predicted, and to test this hypothesis, frogs were observed in the field to determine selected temperatures. They were then brought into the laboratory and performance was tested by sprinting them along a 1m runway at different temperatures. A correlation was found between temperature and sprint speed, with frogs sprinting faster at higher temperatures. However the range of temperatures selected, in the field, by the frogs was very narrow and over this distance there is likely no ecologically significant change in performance level. This could be an artifact of a relatively homogeneous habitat. In a more variable habitat, a more significant difference between possible temperatures and selected ones may be found.