STABLE-ISOTOPE RATIOS INDICATE DIET AND HABITAT USE IN NEW-WORLD MONKEYS

This paper demonstrates the use of stable isotope ratios of carbon and nitrogen in animal tissues for indicating aspects of species behavior al strategy. We analyzed hair from individuals representing four speci es of New World monkeys (Alouatta palliata, the mantled howler; Ateles geoffroyi, the spider monkey; Cebus capucinus, the capuchin; and Brac hyteles arachnoides, the woolly-spider monkey or muriqui) for delta(13 )C and delta(15)N using previously developed methods. There are no sig nificant differences in either carbon or nitrogen ratios between sexes , sampling year, or year of analysis. Seasonal differences in delta(13 )C reached a low level of significance but do not affect general patte rns. Variation within species was similar to that recorded previously within single individuals. The delta(13)C data show a bimodal distribu tion with significant difference between the means. The two monkey pop ulations living in an evergreen forest were similar to each other and different from the other two monkey populations that inhabited dry, de ciduous forests. This bimodal distribution is independent of any parti cular species' diet and reflects the level of leaf cover in the two ty pes of forest. The delta(15)N data display three significantly differe nt modes. The omnivorous capuchins were most positive reflecting a tro phic level offset. The spider monkeys and the muriquis were similar to one another and significantly more positive than the howlers. This di stribution among totally herbivorous species correlates with the inges tion of legumes by the howler monkey population. In combination, these data indicate that museum-curated primate material can be analyzed to yield information on forest cover and diet in populations and species lacking behavioral data. (C) 1997 Wiley-Liss, Inc.