Many reptiles have their sex permanently determined early in development according to the temperature of embryonic incubation. My research on this biological phenomenon examines how different environments select for this mode of sex determination, how the underlying physiological mechanisms operate, and what the consequences are for population dynamics. This research is conducted with collaborators in the U.S.A. and Australia.
Many mammals live for several years, overlapping in their home ranges with daughters more than sons, and experiencing variation in resource availability across space and time. Given such life history and behavioral complexity, are there fitness advantages to producing sons versus daughters under different local conditions? How can we account for such complexity and begin to understand sex ratio variation in mammals?
Parasites are a ubiquitous part of an organism's environment. Hosts can ameliorate the fitness costs of parasites by avoiding or fighting infection. Hosts can also change their behavior or reproductive investment to compensate for the costs of infection. I have examined response of hosts to parasites in several vertebrate species, but mostly focusing on small North American rodents of the genus Peromyscus.
Ground squirrels are distributed widely across western North America, occurring in a diversity of habitats. My research on these animals asked whether the climatic patterns in the deserts of southwest U.S.A. influence the life of ground squirrels.