The Physiological and Ecological Constraints on Spontaneous Torpor Imposed by Diet PUFA Content.

Fordham University, Bronx NY

Investigators

Abstract

Hibernation is utilized by 75 species of mammals to survive seasonally cold conditions. Hibernation has thus been strongly favored by natural selection in many mammalian groups found worldwide. The ecological constraints that may have restricted the evolution of hibernation in mammals are largely unknown. One possible ecological constraint on mammalian torpor may be the concentration of polyunsaturated fatty acids (PUFAs) in the diets of free-ranging mammals. This project will be the first to examine the effects of natural variations in diet PUFA contents on the over-winter survival of free-ranging hibernators, and, determine the physiological/ecological basis for geographic variations in the PUFA contents of the plants consumed by them. The effects of natural variations in diet fatty acid composition on subsequent over-winter survival will be determined in a field study involving golden-mantled ground squirrels in the White Mountains of California. Laboratory feeding/hibernation experiments will be conducted to determine the effects of body temperature on the degree of tissue damage that occurs during hibernation. Field studies on the relationship between elevation, ambient temperature, and plant PUFA content will also be conducted. The project will provide new insights into the physiological ecology of mammalian hibernation. The results of these studies will permit the development of mathematical models to accurately predict the effects of climate warming on populations of hibernating mammals. The participation of historically underrepresented students will be enhanced by including paid summer internships for undergraduates, senior undergraduate thesis projects, and graduate assistantships awarded to students from underrepresented groups.