Meeting Abstract

P3.64  Thursday, Jan. 6  Digestion of lichen by a specialist herbivore – the black-and-white snub-nosed monkey (Rhinopithecus bieti) BISSELL, Heidi; University of Wisconsin-Madison hbissell@wisc.edu

Although many species consume lichen occasionally, Rhinopithecus bieti (the black-and-white snub-nosed monkey, an endangered Asian colobine monkey), is reported to consume a diet containing 60-95% lichens year-round. This dependence on lichen is crucial to conservation of the monkey because lichens are extremely sensitive to environmental change, and the habitat of R. bieti is located in one of the most rapidly changing global environments. Similar changes have caused massive declines in Usnea spp. in the northwestern United States and northern Europe. In other lichen-eating mammals, lichen consumption in excess of 50% of diet dry matter has been observed to depress intake, create negative nitrogen balance, interfere with digestive fermentation, and lead to weight loss over time. In this study we examined the digestibility of the lichen Usnea longissima by captive R. bieti in a series of three-day digestibility trials following adaptation periods of at least 10 days. Four family groups of monkeys (n=4) consumed diets containing between 0 and 15% lichen on a dry matter basis, with the remainder of the diet composed of a standard diet that stayed constant throughout all trials. Dietary lichen proportions of greater than 15% were refused by the monkeys. Using partial digestibility methods, lichen digestibility was estimated to be 91 ± 9% (SD), higher than previously reported for other mammals. The impact of Usnea lichen compounds on fermentative digestion end-products will also be considered.