Dissertation Research: Reproductive Success and Genetic Population Structure In Wedge-Capped Capuchin Monkeys

A cornerstone of the theory of the evolution of most physical and behavioral traits has been the degree to which those traits enhance the reproductive success of the individuals who have them. However, despite its importance in explaining evolution, particularly the evolution of our own behavior and those of other primates, very few studies of wild non-human primates have obtained any estimates of reproductive success. This is due largely to the fact that it is difficult to obtain the long-term demographic data and genetic analyses required to make these estimates.

The proposed study will use molecular genetic markers with a high power of resolution, in conjunction with twenty-one years of demographic and behavioral data, to assess directly reproductive success in a wild New World primate species, the wedge-capped capuchin (Cebus olivaceus). These molecular tools will allow the determination of parentage, other kinds of relatedness (sibling, cousin, etc.), the genetic and social boundaries of maternally related kin, and the degree of relatedness between females and the non-offspring to which they sometimes deliver care. All of these measures will help to define the ways in which certain behaviors render a greater chance of having offspring and other kin, all of whom carry a progenitor's genes. They will also allow us to assess the ways in which individual behaviors and group organization determine the distribution of genetic traits across a population.

Through this study, we will begin to get some idea of the degree to which characteristics such as single male breeding monopoly, female sedentism, and the care for non-offspring and other types of nepotism have real reproductive and genetic consequences. By knowing this, it will provide the basis for more careful explanations of the evolution of primate behaviors, many of which parallel our own.