Meeting Abstract

P2.127  Friday, Jan. 4  Sex differences in freeze tolerance and cryoprotectant mobilization of Spring Peepers (Pseudacris crucifer) and Western Chorus frogs (Pseudacris triseriata) IRWIN, Jason T*; FINKLER, Michael S; Central Washington University; Indiana University Kokomo irwinj@cwu.edu

Several species of temperate hylid frogs are freeze tolerant, surviving the conversion of most of their body water to extracellular ice as they overwinter in terrestrial sites within the frost zone. Survival of freezing is largely due to the cryoprotective effects of glucose, which is rapidly produced from large hepatic glycogen reserves when freezing starts. Given that females, although larger in size, have significantly smaller hepatic reserves than males, we set out to test whether they mobilize less glucose upon freezing and, therefore, are less tolerant of freezing than males. We hypothesized that this difference may be strongest in the spring before feeding commences, when glycogen reserves are typically very low. After collection in late March, few Spring Peepers (Pseudacris crucifer) or Western Chorus frogs (Pseudacris triseriata) survived freezing to -2.5C, but nearly all frogs survived at -1.5C. This lack of a difference is despite the hepatosomatic index of females being 50-60% that of males. Assays of metabolites and energetic content are ongoing and will be discussed.