Abstract # 56:

Scheduled for Thursday, June 21, 2007 05:00 PM-07:00 PM: Session 7 (South Main Hall) Poster Presentation

A Test of Exploitative and Interference Competition in Wild Golden-headed Lion Tamarins (Leontopithecus chrysomelas)

S. Hankerson1, M. Pitts1, J. Dietz1 and B. Raboy2
1University of Maryland, Department of Biology, College Park, MD 20742, USA, 2Smithsonian National Zoological Park, Department of Conservation Biology, 3001 Connecticut Ave NW, Washington, DC, 20008, USA
     Intraspecific competition occurs directly through conflict, or indirectly, through exploitation of shared resources. Both forms influence individual behavior and use of space. We describe foraging behavior and range use in Leontopithecus chrysomelas and use data to test for the presence of intraspecific competition. We studied five groups over 7 years at Una Biological Reserve, Brazil. Behavior of individuals and their geographic location were collected every 20-min., several days a week. Preferential use of overlap areas was determined by comparing the time spent in overlap and exclusive areas to the proportion of these areas within the home range. To test for the existence of exploitative competition, we compared the time spent foraging in overlap and exclusive areas to the total time spent in these areas. For interference competition, we compared the time spent foraging on days with and without encounters. Foraging behaviors accounted for 25-31% of total activity. Neither interference nor exploitative competition was evident through foraging behavior. Time spent foraging in overlap versus exclusive areas was not significantly different. There was no significant difference between foraging on days with and without encounters [F(1,379)=3.12, p=0.08]. L. chrysomelas did spend more time in overlap areas than predicted. Use of overlap areas shows that groups may actively search for neighbors. Frequent fighting between neighboring groups indicates that interference competition does occur, although not necessarily for trophic resources.