International Journal of Primatology

, Volume 22, Issue 2, pp 189–201

Red-Tailed Guenons (Cercopithecus ascanius) and Strychnos mitis: Evidence for Plant Benefits Beyond Seed Dispersal

  • Joanna E. Lambert


I report data collected on red-tailed guenon (Cercopithecus ascanius schmidti) fruit processing behaviors between June 1993 and April 1994. Red-tailed guenons consumed the fruit of Strychnos mitis in 542 of 2,930 fruit-eating events (FEEs). The monkeys spat out cleaned seeds of Strychnos mitis in a majority of these records (477/542; 88%); seeds were occasionally swallowed whole, but only when pulp was unripe (69/542; 12%). In 83% of the FEEs on Strychnos, the red-tailed guenons spat out seeds within 10 m of the removal site; they typically stayed in the same tree while processing fruit, and in 56% of the FEEs, they moved <1 m before spitting seeds. I monitored spat seeds to evaluate the impact of monkey fruit processing on seed fate. Results indicate that 83% of seeds spat out by the red-tailed guenons germinated, while only 12% of unprocessed seeds survived to germination (p < 0.01). Of the processed seeds that germinated, 60% survived to germination and seedling establishment, while only 5% of unprocessed seeds survived to seedling establishment (p < 0.01). Unprocessed seeds were also more likely to be attacked by seed predators (p < 0.01) and fungus (p < 0.01). Although there is generally high mortality in seeds/seedlings, mature trees of Strychnos mitis are found in groves of adults, under which dense populations of seedlings and saplings can occur. These data suggest that Strychnos mitis does not conform to expectations of the Janzen-Connell model of seed escape from parent trees. Instead, I suggest that by removing pulp, a process that results in a reduction of fungal pathogen attack, red-tailed guenons positively effect the seed survivorship of Strychnos mitis. Although this effect has been observed in pulp-cleaning ant species, it is a hitherto undescribed effect of primates on their fruit resources.

Frugivory Kibale National Park, Uganda cercopithecines seed predation Fungal Pathogens 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Augspurger, C. K. (1990). The potential impact of fungal pathogens on tropical plant reproductive biology. In Bawa, K. S., and Hadley, M. (eds), Reproductive ecology of tropical forest plants, The Parthenon Publishing Group, New Jersey, pp. 237–245.Google Scholar
  2. Bell, G. (1992). Five properties of environments. In Grant, R. R. and Horn, H. S. (eds), Mold, molecules, and metazoa: growing points in evolutionary biology, Princeton University Press, New Jersey, pp. 33–35.Google Scholar
  3. Chapman, C. A., Wrangham, R. W., Chapman, L. J., Kennard, D. K., and Zanne, A. E. (1999). Fruit and flower phenology at two sites in Kibale National Park, Uganda. J. Trop. Ecol. 15: 189–211.Google Scholar
  4. Chapman, C. A. (1989). Primate seed dispersal: The fate of dispersed seeds. Biotropica 21: 148–154.Google Scholar
  5. Chapman, C. A., and Chapman, L. J. (1996). Frugivory and the fate of dispersed and nondispersed seeds of six African tree species. J. Trop. Ecol. 12: 1–14.Google Scholar
  6. Chapman, C. A., and Lambert, J. E. (2000). Habitat alteration and the conservation of African primates: A case study of the Kibale National Park, Uganda. Am. J. Primatol. 50: 169–185.Google Scholar
  7. Chapman, C. A., Onderdonk, D. A. (1998). Forests without primates: primate/plant codependency. Am. J. Primatol. 45: 127–141.Google Scholar
  8. Connell, J. H. (1971). On the role of natural enemies in preventing competitive exclusion in some marine animals and in rain forest trees. In den Boer, P. J. and Gradwell, G. R. (eds), Dynamics of Populations, Center for Agricultural Publishing and Documentation, Netherlands, pp. 2948–3100.Google Scholar
  9. Corlett, R. T., and Lucas, P. W. (1990). Alternative seed-handling strategies in primates: Seed-spitting by long-tailed macaques (Macaca fasicularis). Oecologia 82: 166–171.Google Scholar
  10. Dew, J. L., and Wright, P. (1998). Frugivory and seed dispersal by four species of primates in Madagascar's eastern rain forest. Biotropica 30: 425–437.Google Scholar
  11. Flora of Tropical East Africa (1952). London, UK: Crown Agents for Overseas Governments and Administration.Google Scholar
  12. Garber, P. A. (1986). The ecology of seed dispersal in two species of Callitrichid primates (Saguinus mystax and Saguinus fuscicollis). Am. J. Primatol. 10: 155–170.Google Scholar
  13. Howe, H. F. (1989). Scatter-and clump-dispersal and seedling demography: Hypotheses and implications. Oecologia 79: 417–426.Google Scholar
  14. Idani, G. (1986). Seed dispersal by pygmy chimpanzees (Pan paniscus): A preliminary report. Primates 27: 411–447.Google Scholar
  15. Janzen, D. H. (1970). Herbivores and the number of tree species in tropical forest. Am. Nat. 104: 501–528.Google Scholar
  16. Julliot, C. (1996). Seed dispersal by red howling monkeys (Alouatta seniculus) in the tropical rain forest of French Guiana. Int. J. Primatol. 17: 239–258.Google Scholar
  17. Kasenene, J. M. (1980). Plant Regeneration and Rodent Populations in Selectively Felled and Unfelled Areas of the Kibale Forest, Uganda. M.Sc. Thesis, Makerere University, Kampala, Uganda.Google Scholar
  18. Lambert, J. E. (1997). Digestive strategies, fruit processing, and seed dispersal in the chimpanzees (Pan troglodytes) and redtail monkeys (Cercopithecus ascanius) of Kibale National Park, Uganda, Ph.D. thesis, University of Illinois.Google Scholar
  19. Lambert, J. E. (1998a). A field investigation into the behavioral and food processing function of the cercopithecine cheek pouch. Am. J. Phys. Anthropol. (suppl.) 25: 145–146.Google Scholar
  20. Lambert, J. E. (1998b). Primate digestion: Interactions among anatomy, physiology, and feeding ecology. Evol. Anthropol. 7(1): 8–20.Google Scholar
  21. Lambert, J. E. (1998c). Primate frugivory in Kibale National Park, Uganda, and its implications for human use of forest resources. African J. Ecol. 36: 234–240.Google Scholar
  22. Lambert, J. E. (1999). Seed handling in chimpanzees (Pan troglodytes) and redtail monkeys (Cercopithecus ascanius): implications for understanding hominoid and cercopithecine fruit processing strategies and seed dispersal. Am. J. Phys. Anthropol. 109: 365–86.Google Scholar
  23. Lambert, J. E. (2001). Exploring the link between animal frugivory and plant strategies:The case of primate fruit-processing and post-dispersal seed fate. In Levey, D., Silva, W., and Galetti, M. (eds.), Frugivory and Seed Dispersal: Ecological, Evolutionary and Conservation Issues. CABI Publishers, UK, in press.Google Scholar
  24. Lambert, J. E., and Garber, P. A. (1998). Evolutionary and ecological implications of primate seed dispersal. Am. J. Primatol. 45: 9–28.Google Scholar
  25. Lechowicz, M. J., and Bell, B. (1991). The ecology and genetics of fitness in forest plants. II. Microspatial heterogeneity of the edaphic environment. J. Ecol. 79: 687–696.Google Scholar
  26. Lucas, P. W., and Corlett, R. T. (1998). Seed dispersal by long-tailed macaques. Am. J. Primatol. 45: 29–44.Google Scholar
  27. Lwanga, J. S. (1994). The Role of Seed and Seedling Predators and Browsers on the Regeneration of Two Forest Canopy Species (Mimusops bagshawei and Strombosia scheffleri) in Kibale Forest Reserve, Uganda. Ph.D. Thesis, University of Florida, Gainesville, Florida.Google Scholar
  28. Oliveira, P. S., Galetti, M., Fernando P., and Morellato, L. P. C. (1995). Seed cleaning by Mycocepurus goeldii Ants (Attini) facilitates germination in Hymenaea courbaril (Caesalpiniaceae). Biotropica 27: 518–522.Google Scholar
  29. Olupot, W., Chapman, C. A., Brown, C. H., and Waser, P. M. (1994). Mangabey (Cercocebus albigena) population density, group size, and ranging: A 20-year comparison. Am. J. Primatol. 32: 197–205.Google Scholar
  30. Rowell, T. E., and Mitchell, B. J. (1991). Comparison of seed dispersal by guenons in Kenya and capuchins in Panama. J. Trop. Ecol. 7: 269–274.Google Scholar
  31. Struhsaker, T. T. (1997). Ecology of an African rain forest: logging in Kibale and the conflict between conservation and exploitation. University Press of Florida, Gainesville, FL.Google Scholar
  32. Tsingalia, M. H. (1988). Animals and the Regeneration of an African Rainforest Tree. Ph.D. Thesis, University of California, Berkeley.Google Scholar
  33. Tutin, C. E. G., Williamson, E. A., Rogers, M. E., and Fernandez, M. (1991). A case study of a plant-animal relationship: Cola lizae and lowland gorillas in the Lope Reserve, Gabon. J. Trop. Biol. 7: 181–199.Google Scholar
  34. Wrangham, R. W., Chapman, C. A., and Chapman, L. J. (1994). Seed dispersal by forest chimpanzees in Uganda. J. Trop. Ecol. 10: 355–368.Google Scholar
  35. Yumoto, T., Noma, N., and Maruhashi, T. (1998). Cheek-pouch dispersal of seeds by Japanese monkeys (Macaca fuscata yakui) on Yakushima Island, Japan. Primates 39: 325–338.Google Scholar

Copyright information

© Plenum Publishing Corporation 2001

Authors and Affiliations

  • Joanna E. Lambert
    • 1
  1. 1.Department of AnthropologyUniversity of OregonEugene

Personalised recommendations