My research interests center on the evolution of mating systems. I am especially interested in the links between spatial ecology, behavior, morphology and physiology, and the fitness benefits and costs arising from each of these attributes at the individual and population level. In my doctoral research, I combined field (e.g., radio-tracking, GIS analysis) and laboratory (e.g., endocrinological, histological, molecular) approaches to address questions and hypotheses about the spatial ecology and reproductive physiology of copperhead snakes. These data, along with phylogenetic information, provide the raw materials from which I am developing an integrated framework to study the ecology and evolution of mating systems and sexual selection in these and other snakes.
In my in situ field studies of spatial ecology and reproduction, I have focused on characterizing the proximate environmental factors influencing reproduction in individuals. For example, my dissertation work on copperheads in Connecticut showed that males have a relatively small window of time in late summer to locate highly dispersed mates. In response to spatial patterns of females, males increase their home range size and movement levels. Concomitant with these changes are increases in plasma sex steroids, which are thought to be necessary to drive sexual behavior in males (but see below). In addition, selection upon males for efficient mate location ability is manifested in a sexually dimorphic tongue structure―the first instance of such in any tetrapod vertebrate studied to date.
My future goals are to design experiments in the field and laboratory to further test the proximate determinants of mating success. Contrary to current paradigms, variation in mating success and perhaps even fitness in male copperheads appears to be strongly influenced not only by the hormonal environment, but by the interaction between individual motivation and circulating androgen levels as well. Therefore, one future direction of my research is to examine male behavior and fitness in the context of motivational variation in male mate-seeking behavior.