In many species of mammals, males compete physically for access to mating partners, and traits that confer an advantage in fighting are favored. In other species, however, males seldom interact aggressively, yet some individuals still acquire more mates than others. Dr. Schwagmeyer will conduct research on a species belonging to this second type. She will investigate features of potential importance to male reproductive success in a mating system in which aggression and combat play trivial roles. In previous research on thirteen-lined ground squirrels, Dr. Schwagmeyer found that breeding males spend most of their time simply searching for sexually receptive females. Usually the number of mates that a male acquires is exactly equal to the number of sexually receptive females that he finds; thus, a male's skill in finding females is critical in determining his reproductive success. Dr. Schwagmeyer will carry out a three- phase field study to examine how males actually locate a female during the 4 to 5 hours that she is sexually receptive. The study will involve (1) monitoring male visits with females to determine if males can "predict" when a particular female will become sexually available, (2) temporarily removing females to assess whether or not males remember the geographic locations of females they have encountered on previous days, and (3) observing how males' abilities to remember the locations of females, and to learn other spatial tasks, influence their mating success. This research project represents a unique combination of the behavioral ecology of mating systems with the experimental psychology of spatial learning and memory. Thus, in addition to important and novel specific findings, the work offers new perspectives for both fields of science.
