Journal of Chemical Ecology

, Volume 28, Issue 5, pp 921–937 | Cite as

Effects of Large Mammalian Herbivores and Ant Symbionts on Condensed Tannins of Acacia drepanolobium in Kenya

  • David WardEmail author
  • Truman P. Young


Condensed tannins have been considered to be important inducible defenses against mammalian herbivory. We tested for differences in condensed tannin defenses in Acacia drepanolobium in Kenya over two years among different large mammalian herbivore treatments [total exclusion, antelope only, and megaherbivore (elephants and giraffes) + antelope] and with four different ant symbiont species on the trees. We predicted that (1) condensed tannin concentrations would be lowest in the mammal treatment with the lowest level of herbivory (total exclusion), (2) trees occupied by mutualist ants that protect the trees most aggressively would have lower levels of tannins, and (3) if chemical defense production is costly, there would be a trade-off between tannin concentrations, growth, and mechanical defenses. Mean tannin concentrations increased from total exclusion treatments to wildlife-only treatments to megaherbivore + antelope treatments. In 1997, condensed tannin concentrations were significantly lower in trees occupied by the ant Crematogaster nigriceps, the only ant species that actively removed axillary buds. Contrary to our prediction, trees occupied by ant species that protect the trees more aggressively against mammalian herbivores did not have lower overall levels of condensed tannins. There was no consistent evidence of a trade-off between tannin concentrations and growth rate, but there was a positive correlation between mean thorn length and mean tannin concentrations across species of ant inhabitants and across herbivore treatments in 1997. Contrary to our expectation, trees had higher tannin concentrations in the upper parts of the canopy where there is little herbivory by mammals.

Induced defenses condensed tannins Acacia mammalian herbivory ants mutualism 


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  1. Briggs, M. A. and Schultz, J. C.1990.Chemical defense production in Lotus corniculatus. II. Trade-offs among growth, reproduction, and defense. Oecologia83:32–37.Google Scholar
  2. Brooks, R. and Owen Smith, N.1994.Plant defenses against mammalian herbivores: are juvenile Acacia more heavily defended than mature trees?Bothalia24:211–215.Google Scholar
  3. Bryant, J. P., Chapin, F. S., and Klein, D. R.1983.Carbon/nutrient balance of boreal plants in relation to vertebrate herbivory.Oikos40:357–368.Google Scholar
  4. Bryant, J. P., Chapin, F. S., Reichardt, P. B., and Clausen, T. P. 1987. Response of winter chemicaldefense in Alaska paper birch and green alder to manipulation of plant carbon/nutrient balance. Oecologia 72:510–514.Google Scholar
  5. Bryant, J. P., Reichardt, P. B., and Clausen, T. P. 1992.Chemically mediated interactions between woody plants and browsing mammals.J. Range Manage.45:18–24.Google Scholar
  6. Coe, M. and Beentje, H. 1991.A Field Guide to the Acacias of Kenya.Oxford University Press, Oxford.Google Scholar
  7. Cooper, S. M. and Owen-Smith, N. 1985.Condensed tannins deter feeding by browsing ungulates in a South African savanna.Oecologia67:142–146.Google Scholar
  8. Cooper, S.M. and Owen-Smith, N.1986. Effects of plant spinescence on large mammalian herbivores.Oecologia68:446–455.Google Scholar
  9. Cooper, S.M., Owen-Smith, N., and Bryant, J. P. 1988.Foliage acceptability to browsing ruminants in relation to leaf chemistry of woody plants in a South African savanna.Oecologia75:336–342.Google Scholar
  10. Danell, K. and Huss-Danell, K. 1985. Feeding by insects and hares on birches earlier affected by moose browsing. Oikos44:75–81.Google Scholar
  11. Du Toit, J., Bryant, J. P., and Frisby, K. 1990. Regrowth and palatability of Acacia shoots following pruning by African savanna browsers.Ecology71:149–154.Google Scholar
  12. Furstenburg, D. and van Hoven, W.1994. Condensed tannin as antidefoliate agent against browsing by giraffe (Giraffa camelopardis) in the Kruger National Park.Comp. Biochem. Physiol. B 107:425–431.Google Scholar
  13. Gowda, J. H. 1996a. Plant defenses: Influence on plant–animal interactions in eastern Africa. PhD thesis. Swedish University of Agricultural Sciences, Umea.Google Scholar
  14. Gowda, J. H. 1996b. Spines of Acacia tortilis: What do they defend and how?Oikos 77:279–284.Google Scholar
  15. Gowda, J. H. 1997.Physical and chemical response of juvenile Acacia tortilis trees to browsing. Experimental evidence.Funct. Ecol. 11:106–111.Google Scholar
  16. Hagerman, A. E. and Butler, L. G. 1989.Choosing appropriate methods and standards for assaying tannin. J. Chem. Ecol. 15:1795–1810.Google Scholar
  17. Herms, D. A. and Mattson, W. J. 1992. The dilemma of plants: To grow or defend.Q. Rev. Biol. 67:283–335.CrossRefGoogle Scholar
  18. Hocking, B. 1970. Insect association with swollen thorn Acacias.Trans. R. Entomol. Soc. 122:211–255.Google Scholar
  19. Karban, R. and Baldwin, I. T. 1997. Induced Responses to Herbivory.University of Chicago Press, Chicago, Illinois.Google Scholar
  20. Karban, R., Agrawal, A., and Mangel, M. 1997. The benefits of induced defenses against herbivores.Ecology 78:1351–1355.Google Scholar
  21. Lundberg, P. and Astrom, M.1990. Low nutritive quality as a defense against optimally foraging herbivores.Am. Nat. 135:547–562.Google Scholar
  22. Madden, D. and Young, T. P.1992.Ants as alternative defenses in spinescent Acacia drepanolobium. Oecologia91:235–238.Google Scholar
  23. McNaughton, S. J. 1983. Compensatory plant growth as response to herbivory.Oikos 40:329–336.Google Scholar
  24. Mcnaughton, S. J. and Tarrants, J. L. 1983. Grass leaf silicification: natural selection for an inducible defense against herbivores.Proc. Natl. Acad. Sci. USA 80:790–791.Google Scholar
  25. Milewski, A. V., Young, T. P., and Madden, D. 1991.Thorns as induced defenses: Experimental evidence.Oecologia 86:70–75.Google Scholar
  26. Myers, J. H. and Bazeley, D. 1991. Thorns, spines, prickles, and hairs: are they stimulated by herbivory and do they deter herbivores? pp. 326–343, in D. J. Tallamy and M. J. Raupp (eds.). Phytochemical Induction by Herbivores,Academic Press, New York.Google Scholar
  27. Owen-Smith, N. 1993. Woody plants, browsers and tannins in southern African savannas.S. Afr. J. Sci. 89:505–510.Google Scholar
  28. Palo, R. T., Gowda, J., and Hogberg, P. 1993. Species height and root symbiosis, two factors influencing antiherbivore defense of woody plants in East African savanna.Oecologia 93:322–326.Google Scholar
  29. Rhoades, D. F. 1979. Evolution of plant chemical defense against herbivores, pp. 3–54, in G. A. Rosenthal and D. H. Janzen (eds.). Herbivores, Their Interactions with Secondary Plant Metabolites. Academic Press, New York.Google Scholar
  30. Robbins, C. T., Mole, S., Hagerman, A. E., and Hanley, T. A.1987. Role of tannins in defending plants against ruminants: Reduction in dry matter digestion?Ecology68:1606–1615.Google Scholar
  31. Rohner, C. and Ward, D. 1997. Chemical and mechanical defense against herbivory in two sympatric species of desert Acacia.J. Veg. Sci.8:717–726.Google Scholar
  32. Rosenthal, J. P. and Kotanen, P.M. 1994. Terrestrial plant tolerance to herbivory.Trends Ecol. Evol. 9:145–148.Google Scholar
  33. Ross, J. H.1979.A conspectus of the African Acacia species. Mem. Bot. Surv. S. Afr.44:1–155.Google Scholar
  34. Scholes, R. J. and Walker, B. H. 1993. An African Savanna: Synthesis of the Nylsvley Study. Cambridge University Press, Cambridge.Google Scholar
  35. Silvertown, J. and Dodd, M. E. 1996.Comparing plants and connecting traits. Phil. Trans. R. Soc. London B 351:1233–1239.Google Scholar
  36. Simms, E. L. 1992.Costs of plant resistance to herbivory, pp. 392–425, in R. S. Fritz and E. L. Simms (eds.). Plant Resistance to Herbivores and Pathogens: Ecology, Evolution and Genetics.University of Chicago Press, Chicago, Illinois.Google Scholar
  37. Teague, W. R. 1989.Effect of intensity and frequency of defoliation on aerial growth and carbohydrate reserve levels in Acacia karroo plants.J. Grassl. Soc. S. Afr.6:132–138.Google Scholar
  38. Van der Meijden, E., Wijn, M., and Verkaar, H. J. 1988. Defence and regrowth, alternative plant strategies in the struggle against herbivores.Oikos 51:355–363.Google Scholar
  39. Van Noordwijk, A. J. and de Jong, G. 1986.Acquisition and allocation of resources: their influence on variation in life history tactics.Am. Nat.128:137–142.CrossRefGoogle Scholar
  40. Ward, D., Spiegel, M., and Saltz, D. 1997.Gazelle herbivory and interpopulation differences in calcium oxalate content of leaves of a desert lily.J. Chem. Ecol 23:333–346.Google Scholar
  41. Waterman, P. G. and Mole, S. 1994.Analysis of Phenolic Plant Metabolites.Blackwell Science, Oxford.Google Scholar
  42. Wrangham, R. W. and Waterman, P. G. 1981.Feeding behaviour of vervet monkeys on Acacia tortilis and Acacia xanthophloea: With special reference to reproductive strategies and tannin production.J. Anim. Ecol.50:715–731.Google Scholar
  43. Young, T. P. 1987.Increased thorn length in Acacia drepanolobium—aninduced response to browsing. Oecologia 71:434–438.Google Scholar
  44. Young, T. P. and Okello, B. D.1998. Relaxation of an induced defence after exclusion of herbivores: Spines on Acacia drepanolobium.Oecologia 111:508–513.Google Scholar
  45. Young, T. P., Stubblefield, C. H., and Isbell, I.A.1997.Ants on swollen-thorn acacias: Coexistence in a simple system.Oecologia 109:98–107.Google Scholar
  46. Young, T. P., Okello, B. D., Kinyua, D., and Palmer, T.M.1998. KLEE: A long-term multi-species herbivore exclusion experiment in Laikipia, Kenya. Afr. J. Range Forage Sci.14:94–102.Google Scholar
  47. Zangerl, A. R. and Bazzaz, F. A. 1992.Theory and pattern in plant defence allocation, pp. 363–391,in R. S. Fritz and E. L. Simms (eds.). Plant Resistance to Herbivores and Pathogens: Ecology, Evolution and Genetics.University of Chicago Press, Chicago, Illinois.Google Scholar

Copyright information

© Plenum Publishing Corporation 2002

Authors and Affiliations

  1. 1.Mpala Research CenterNanyukiKenya
  2. 2.Department of Environmental HorticultureUniversity of CaliforniaDavis

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