American Journal of Primatology 68:397–409 (2006) RESEARCH ARTICLE Life on the Edge: Gastrointestinal Parasites From the Forest Edge and Interior Primate Groups COLIN A. CHAPMAN 1,2Ã , MICHAELA L. SPEIRS 1 , THOMAS R. GILLESPIE 3– 5 TIMOTHY HOLLAND 6 , AND KIERSTEN M. AUSTAD 7 1 Anthropology Department and McGill School of Environment, McGill University, Montreal, Canada 2 Wildlife Conservation Society, Bronx, New York 3 Department of Anthropology, University of Illinois, Urbana, Illinois 4 Program in Ecology and Evolutionary Biology, University of Illinois, Urbana, Illinois 5 Department of Veterinary Pathobiology, University of Illinois, Urbana, Illinois 6 Department of Biology, McGill University, Montreal, Quebec, Canada 7 Department of Psychology, University of West Florida, Pensacola, Florida Humans are responsible for massive changes to primate habitats, and one unanticipated consequence of these alterations may be changes in host–parasite interactions. Edges are a ubiquitous aspect of human disturbance to forest landscapes. Here we examine how changes associated with the creation of edges in Kibale National Park, Uganda, alter the parasite community that is supported by two species of African colobines: the endangered red colobus (Piliocolobus tephrosceles) and the black-and-white colobus (Colobus guereza). An analysis of 822 fecal samples from edge and forest interior groups revealed no difference in the richness of parasite communities (i.e., the number of parasite species recovered from the host’s fecal sample). However, for both species the proportion of individuals with multiple infections was greater in edge than forest interior groups. The prevalence of specific parasites also varied between edge and forest interior groups. Oesophagostomum sp., a potentially deleterious parasite, was 7.4 times more prevalent in red colobus on the edge than in those in the forest interior, and Entamoeba coli was four times more prevalent in red colobus on the edge than in animals from the forest interior. Environmental contamination with parasites (measured as parasite eggs/gm feces) by red colobus from the edge and forest interior differed in a similar fashion to prevalence for red colobus, but it did not differ for black-and-white colobus. For example, egg counts of Oesophagostomum sp. were 10 times higher in red colobus from the edge than in those from the interior. The less severe infections Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ajp.20233 Received 6 May 2005; revised 25 July 2005; revision accepted 28 July 2005 Contract grant sponsor: Canadian Research Chairs Program; Contract grant sponsor: Wildlife Conservation Society (WCS); Contract grant sponsor: National Science and Engineering Research Council (NSERC) of Canada; Contract grant sponsor: National Center for Environmental Research, U.S. EPA; Contract grant sponsor: National Science Foundation (NSF); Contract grant number: SBR-990899. Ã Correspondence to: Colin A. Chapman, Anthropology Department and McGill School of Environment, 855 Sherbrooke St. West, McGill University, Montreal H3A 2T7, Canada. E-mail: Colin.chapman@mcgill.ca r r 2006 Wiley-Liss, Inc.