9600578 Kenagy This Americas Program award will support a collaborative research project between Dr. George Kenagy, University of Washington, Seattle, and Dr. Francisco Bozinovic, Pontificia Universidad Catolica de Chile. The objective of the proposed project is to characterize the profile of energy expenditure for breeding in the degu, a rodent belonging to a South American group, the Caviomorpha. This group undertakes a lengthy gestation leading to birth of highly precocial young requiring only a brief period of suckling. The study will seek to identify the peak demand and expenditure of energy and to see how these correspond to the maximal performance capacities of the selected species. Stable isotope technology will be used to measure rates of energy expenditure. An initial assessment will be made of the link between energetics and the mode of life history that has evolved in caviomorph rodents. Life history theory has produced the idea that for iteroparous animals an increase in current reproductive output should have a negative impact on future reproductive potential and survival. Evidence from genetic correlations and individual variation in performance continues to lend support to the possibility that energy relations are indeed a link between organismal performance and fitness. This study will address the role of energy in shaping life histories by providing insights into the process of energy use in a natural mammalian population and its relation to maximum energetic capacities of females during gestation or lactation. This will include the mammalian maternal strategy of producing precocial young. ***
