Professor Department of Ecology and Evolution SUNY at Stony Brook State University of New York

Education : Lab Page : Research Interests :

Ph.D. 1985, University of Washington Janson's Lab Janson was the chairperson (until Aug. 2006) of the department of Ecology and Evolution. Charles Janson's research spans two distinct topic in evolutionary ecology: (1) ecological pressures on socical behavior in primates, and (2) ecological and evolutionary consequences of seed dispersal in plants. He has spent over 70 months observing the ecology and social behavior of several primate species. He is studying how an individual's social behavior interacts with external aspects of the environment to affect a variety of proximate correlates of fitness such as energy intake, predation risk, and mate choice. For instance, he analyzed how food productivity in patches interacts with group size and individual social status to affect an individual's food intake in brown capuchin monkeys. He then tested these patterxns experimentally using spatial arrays of artificial food patches in a wild capuchin monkey population in Argentina. Extending the analysis across species, he found that the greater the degree of food competition within groups, the smaller the mean group size of fruit-eating primate species. Current grant-supported work intends to understand the rules used by primates to decide which of many resources available to visit, and in what order. Understanding the cognitive processes underlying spatial foraging decisions may be crucial to explaining the link between food availability and primate social behavior. Ongoing research focuses on the direct and indirect effects of predation and infanticide on primate social structure. >From such studies, he hopes to build realistic models of the evolution of primate social behavior. Janson also is interested in the evolution of seed dispersal by animals, in particular the relative roles of adaptation and phylogeny in producing the patterns of fruit traits observed among plants now. His approach combines studies of selection on fruit traits in temperate communities, comparisons among fruit traits of species in the biodiverse tropics, and analysis of reflectance characteristics of temperate fruits. His favorite current puzzle is understanding why most bird-dispersed plants have either red or black fruits, when these colors seem to differ markedly in their ability to attract foraging animals. Janson was the chairperson (from Sept. 2002 to Aug. 2006) of the department of Ecology and Evolution.