Meeting Abstract

84.1  Sunday, Jan. 6  Turning up the Heat: Investigating the Physiological Effects of Climate Change on Mammalian Herbivores KURNATH, P.*; DEARING, M.D.; Univ. of Utah, Salt Lake City; Univ. of Utah, Salt Lake City patrice.kurnath@utah.edu

Climate change is causing range shifts and population declines in many animal populations, particularly mammalian herbivores. One hypothesis to explain these changes in mammalian herbivores is that plant secondary compounds may be perceived as more toxic due to decreased liver metabolism at warmer ambient temperatures compared to cooler temperatures. The phenomenon of temperature-dependent toxicity (TDT) has been documented in pharmacological studies in laboratory rodents, but has not been extensively explored in wild mammalian herbivores. To test for TDT, we investigated how ambient temperature impacts liver metabolism in the desert woodrat, Neotoma lepida, by using hypnotic state assays. In a cross-over design, wild caught N. lepida (N=26) were housed at two ambient temperatures (warm=29°C, cool=21°C) for either 30 days or 3 hours to capture ecologically relevant situations in the wild (i.e., within season or access to microclimates). After each temperature exposure, animals were given a hypnotic agent (hexobarbital via intraperitoneal injections 100mg/kg), which was used as a proxy for liver function with longer sleep times indicating decreased liver function. The average sleep time of woodrats acclimated to warm temperatures for 30 days was almost 50% longer than cool-acclimated woodrats and almost 30% longer after the 3 hour exposure to warm versus cool temperatures (paired t-tests, p<0.01). These results demonstrate that warmer ambient temperatures adversely affect liver function, even within a short period of time, and may provide a physiological mechanism through which climate change acts on herbivorous mammals.