Abstract # 173:

Scheduled for Sunday, September 18, 2011 07:00 PM-09:00 PM: Session 23 (Salon G (Sixth Floor)) Poster Presentation


MIXED-SPECIES ASSOCIATIONS OF WESTERN RED COLOBUS (PILIOCOLOBUS BADIUS) AND GREEN VERVETS (CHLOROCEBUS SABAEUS) IN THE GAMBIA

C. K. Wolovich1,2,3, K. Skrabacz3, E. Egorova3, M. Boemio3 and K. M. Zdilla3
1MacMurray College, Department of Biology, Jacksonville, IL 62650, USA, 2DuMond Conservancy for Primates and Tropical Forests, Inc., 3St. Mary's College of Maryland
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     West African populations of red colobus (Piliocolobus badius) and green vervets (Chlorcebus sabaeus) form mixed-species associations. We aimed to characterize the behaviors of these species in the presence and absence of one another to determine potential costs and benefits of these associations. We observed red colobus and green vervets in Bijilo Forest Park and Abuko Nature Reserve in The Gambia (Sept-Dec 2009) and used instantaneous sampling during ten-minute observation periods [n = 90] to score their behaviors (foraging, moving, resting, alert, social). When the other species was present, we simultaneously observed the nearest heterospecific. Mixed-species associations were frequent [43% of observation periods] and the two species were even observed to allogroom one another. The proportion of sampling points that green vervets and red colobus monkeys engaged in various activities did not differ in the presence and absence of heterospecifics [Mann-Whitney U tests, p > 0.05]. Red colobus monkeys synchronized their behaviors with nearby heterospecifics more so than would be expected due to chance [One sample t-test, expected = 0.20 of sampling points, observed = 0.32 of sampling points, t = 2.33, df = 13, p = 0.037]. Low levels of interspecific feeding competition are likely because C. sabaeus is omnivorous and mainly terrestrial whereas P. badius is highly folivorous and arboreal. Potential antipredator benefits of large groups may maintain these mixed-species associations.