Abstract
Studies of the diet of different groups of the same species allow us to understand intraspecific dietary variability. I collected dietary data from six neighboring groups of redtail monkeys (Cercopithecus ascanius schmidti) and three hybrid monkeys over 12 years at Ngogo and from one group at Kanyawara in Kibale National Park, Uganda and compared these results with previous studies of redtail diets elsewhere in Kibale and from the Kakamega Forest of Kenya. I scored feeding as a particular monkey ingesting a species-specific plant part, or catching insects from a species-specific substrate. A new feeding score was tallied for the same combination of parameters only after a 30-min interval or if the identity of one of the three parameters changed. I counted trees along transects in the home ranges of the two main study groups to calculate food selection ratios. I used chi-square tests to compare diets between groups and time periods and Spearman rank correlation coefficient tests for dietary correlates. These comparisons reveal considerable variation in plant parts and species eaten by redtails between months, years, and neighboring groups with overlapping ranges. Selection ratios show that some tree species are important sources of plant food, while others are more important as sources of invertebrates. The high incidence of insectivory by redtails demonstrates another ecological role they play in addition to seed dispersal. The intrademic variation in diets I describe for Kibale was often as great as and sometimes greater than the interdemic variation. The diets of the hybrid monkeys at Ngogo differed in some ways from their parental species, particularly in their greater consumption of invertebrates. Introgression may have led to some of these differences within and between redtail demes. The pronounced variability in redtail diets demonstrates why a typological perspective of species is unwarranted and that the validity of interspecific comparisons requires a thorough understanding of intraspecific variation.
Similar content being viewed by others
References
Beentje, H. (1994). Kenya trees, shrubs, and lianas. Nairobi: National Museums of Kenya.
Bryer, M. A. H., Chapman, C. A., & Rothman, J. M. (2013). Diet and polyspecific associations affect spatial patterns among redtail monkeys (Cercopithecus ascanius). Behaviour, 150(3–4), 277–293.
Bryer, M. A. H., Chapman, C. A., Raubenheimer, D., Lambert, J. E., & Rothman, J. M. (2015). Macronutrient and energy contributions of insects to the diet of a frugivorous monkey (Cercopithecus ascanius). International Journal of Primatology, 36(4), 839–854.
Butynski, T. M. (1990). Comparative ecology of blue monkeys (Cercopithecus mitis) in high- and low-density subpopulations. Ecological Monographs, 601(1), 1–26.
Chapman, C. A., & Chapman, L. J. (2000). Constraints on group size in red colobus and red-tailed guenons: Examining the generality of the ecological constraints model. International Journal of Primatology, 21(4), 565–585.
Chapman, C. A., Chapman, L. J., Cords, M., Gathua, J. M., Gautier-Hion, A., et al (2002). Variation in the diets of Cercopithecus species: Differences within forests, among forests, and across species. In M. E. Glenn & M. Cords (Eds.), The guenons: Diversity and adaptation in African monkeys (pp. 325–350). New York: Kluwer Academic/Plenum Publishers.
Chapman, C. A., Chapman, L. J., Struhsaker, T. T., Zanne, A. E., Clark, C. J., & Poulsen, J. R. (2005). A long-term evaluation of fruiting phenology: Importance of climate change. Journal of Tropical Ecology, 21(1), 31–45.
Conklin-Brittain, N. L., Wrangham, R. W., & Hunt, K. D. (1998). Dietary response of chimpanzees and cercopithecines to seasonal variation in fruit abundance. II. Macronutrients. International Journal of Primatology, 19(6), 971–998.
Cords, M. (1986). Interspecific and intraspecific variation in diet of two forest guenons. Cercopithecus ascanius and C. mitis. Journal of Animal Ecology, 55, 811–827.
Cords, M. (1987a). Forest guenons and patas monkeys: Male-male competition in one-male groups. In B. B. Smuts, D. L. Cheney, R. M. Seyfarth, R. W. Wrangham, & T. T. Struhsaker (Eds.), Primate societies (pp. 98–111). Chicago: University of Chicago Press.
Cords, M. (1987b). Mixed-species association of Cercopithecus monkeys in the Kakamega Forest, Kenya. Berkeley: University of California Press.
Crawley, M. J. (1983). Herbivory, the dynamics of animal-plant interactions. Berkeley and Los Angeles: University of California Press.
Dunham, N. T. (2017). Feeding ecology and dietary flexibility of Colobus angolensis palliatus in relation to habitat disturbance. International Journal of Primatology, 38, 553–571.
Fashing, P. J. (2001). Feeding ecology of guerezas in the Kakamega Fores, Kenya: The importance of Moracease fruit in their diet. International Journal of Primatology, 22, 579–609.
Gathua, M. (2000). Intraspecific variation in foraging patterns of redtail monkeys (Cercopithecus ascanius) in the Kakamega Forest, Kenya. Ph.D. thesis, Columbia University, New York.
Gautier-Hion, A. (1980). Seasonal variations of diet related to species and sex in a community of Cercopithecus monkeys. Journal of Animal Ecology, 49, 237–269.
Gautier-Hion, A. (1988). The diet and dietary habits of forest guenons. In A. Gautier-Hion, F. Bourliere, J-P. Gautier, & J. Kingdon (Eds.), A primate radiation: Evolutionary biology of the African guenons (pp. 257–283). Cambridge: Cambridge University Press.
Hamilton, A. C. (1981). A field guide to Uganda forest trees. Kampala, Uganda: Makerere University Printery.
Lambert, J. E. (2002). Resource switching and species coexistence in guenons: A community analysis of dietary flexibility. In M. E. Glenn & M. Cords (Eds.), The guenons: Diversity and adaptation in African monkeys (pp. 309–323). New York: Kluwer Academic/Plenum Publishers.
Mani, M. S. (1964). Ecology of plant galls. The Hague: Dr. W. Junk Publishers.
Mayr, E. (1959). Darwin and the evolutionary theory in biology. In B. J. Meggers (Ed.), Evolution and anthropology: A centennial appraisal (pp. 3–12). Washington, DC: Anthropological Society of Washington.
Rode, K. D., Chapman, C. A., Chapman, L. J., & McDowell, L. R. (2003). Mineral resource availability and consumption by colobus in Kibale National Park, Uganda. International Journal of Primatology, 24(3), 541–573.
Rudran, R. (1978). Socioecology of the blue monkeys (Cercopithecus Mitis Stuhlmanni) of the Kibale Forest, Uganda. Smithsonian contributions to zoology. Washington, DC: Smithsonian Institution Press.
Struhsaker, T. T. (1975). The red colobus monkey. Chicago and London: University of Chicago Press.
Struhsaker, T. T. (1978a). Food habits of five monkey species in the Kibale Forest, Uganda. In D. J. Chivers & J. Herbert (Eds.), Advances in primatology, Vol. 1: Behaviour (pp. 225–248). London, New York, and San Francisco: Academic press.
Struhsaker, T. T. (1978b). Interrelations of red colobus monkeys and rain-Forest trees in the Kibale forest, Uganda. In G. G. Montgomery (Ed.), The ecology of arboreal folivores: A symposium held at the conservation and research center, National Zoological Park, Smithsonian Institution, may 29–31, 1975 (pp. 397–422). Washington, DC: Smithsonian Institution Press.
Struhsaker, T. T. (1980). Comparison of the behaviour and ecology of red colobus and redtail monkeys in the Kibale Forest, Uganda. African Journal of Ecology, 18(1), 33–51.
Struhsaker, T. T. (1988). Male tenure, multi-male influxes, and reproductive success in redtail monkeys (Cercopithecus ascanius). In A. Gautier-Hion, F. Bourliere, J-P. Gautier, & J. Kingdon (Eds.), A primate radiation: Evolutionary biology of the African guenons (pp. 340–363). Cambridge: Cambridge University Press.
Struhsaker, T. T. (1997). Ecology of an African rain forest: Logging in Kibale and the conflict between conservation and exploitation. Gainesville: University Press of Florida.
Struhsaker, T. T. (2008). Demographic variability in monkeys: Implications for theory and conservation. International Journal of Primatology, 29(1), 19–34.
Struhsaker, T. T. (2010). The red colobus monkeys. Oxford: Oxford University Press.
Struhsaker, T. T., & Leland, L. (1988). Group fission in redtail monkeys (Cercopithecus ascanius) in the Kibale Forest, Uganda. In A. Gautier-Hion, F. Bourliere, J-P. Gautier, & J. Kingdon (Eds.), A primate radiation: Evolutionary biology of the African guenons (pp. 364–388). Cambridge: Cambridge University Press.
Struhsaker, T. T., Butynski, T. M., & Lwanga, J. S. (1988). Hybridization between redtail (Cercopithecus ascanius schmidti) and blue (Cercopithecus mitis stuhlmanni) monkeys in the Kibale Forest, Uganda. In A. Gautier-Hion, F. Bourliere, J-P. Gautier, & J. Kingdon (Eds.), A primate radiation: Evolutionary biology of the African guenons (pp. 477–497). Cambridge: Cambridge University Press.
Wrangham, R. W., Conklin-Brittain, N. L., & Hunt, K. D. (1998). Dietary response of chimpanzees and Cercopithecines to seasonal variation in fruit abundance. I. Antifeedants. International Journal of Primatology, 19(6), 949–970.
Acknowledgments
I thank Dr. Alan Hamilton, the late Tony Katende, and the staff at the National Museums of Kenya and Botanic Gardens Kew for plant identifications and Lysa Leland for field assistance. My research was funded by the New York Zoological Society, African Wildlife Foundation, and the National Geographic Society grant number 2929-84. The Department of Zoology, Makerere University was my affiliation in Uganda and I was permitted to study in Kibale by the President’s Office of Uganda, Uganda National Research Council, and the Uganda Forest Department. I thank all of these organizations and institutions. I thank two anonymous reviewers and Drs. Jessica Rothman and Joanna Setchell for constructive comments on my manuscript and Dr. Christine Wall for statistical advice.
Author information
Authors and Affiliations
Corresponding author
Additional information
Handling Editor: Joanna M. Setchell.
Rights and permissions
About this article
Cite this article
Struhsaker, T.T. Dietary Variability in Redtail Monkeys (Cercopithecus ascanius schmidti) of Kibale National Park, Uganda: the Role of Time, Space, and Hybridization. Int J Primatol 38, 914–941 (2017). https://doi.org/10.1007/s10764-017-9988-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10764-017-9988-3