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Life history and environmental factors driving variation in mammalian sex allocation

PI(s): Beaux Berkeley (James Madison University (Harrisonburg,VA))
Start Date: 8-Jun-2012
End Date: 27-Jul-2012
Keywords: mating systems, adaptation

Over the past 40 years, sex allocation (SA) has been a rigorously tested theory, as having the ability to choose offspring sex would have significant agricultural, wildlife and human family planning benefits, yet the experimental results reported are often contradictory. Several main theories, the Trivers-Willard hypothesis, local resource competition and its corollary, local resource enhancement, have been proposed to explain the observed variation.1-3 In the past ten years, the physiological mechanisms responsible for sex allocation have been suggested to be changes in circulating glucose or steroid hormone concentrations around the time of conception.4-6 Part of the confusion in understanding SA is that many different species and different levels of variables (i.e. physiological, endocrinological, ecological) have been analyzed. An organized systematic summary of the factors and degree of variation in the SA response in different mammalian taxa does not exist. The objective of this proposal is to construct a careful and accurate database collating existing literature describing factors influencing sex allocation in mammals with life history, geographic and taxonomic data in order to identify patterns in the drivers of the SA response. The resulting database would be publically available to all researchers in order to increase understanding of SA and development of new research projects.