Chemical Signals of Elephant Musth: Temporal Aspects of Microbially-Mediated Modifications
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Mature male African (Loxodonta africana) and Asian (Elephas maximus) elephants exhibit periodic episodes of musth, a state in which serum androgens are elevated, food intake typically decreases, aggressiveness often increases, and breeding success is enhanced. Urine is a common source of chemical signals in a variety of mammals. Elephants in musth dribble urine almost continuously for lengthy periods, suggesting that the chemicals in their urine may reveal their physiological condition to conspecifics. We investigated the volatile urinary chemicals in captive male elephants using automated solid phase dynamic extraction (SPDE) and gas chromatography–mass spectrometry (GC-MS). We found higher levels of alkan-2-ones, alkan-2-ols, and some aromatic compounds in urine from males in musth than in urine from non-musth males or from females. Levels of ketones and alcohols increased as the urine aged, likely due to microbial metabolism of fatty acids. Protein-derived aromatic metabolites also increased in abundance after urination, likely due to microbial hydrolysis of hydrophilic conjugates. We suggest that microbes may play an important role in timed release of urinary semiochemicals during elephant musth.
Key WordsAfrican elephant Loxodonta africana Asian elephant Elephas maximus Microbial metabolism Mammalian chemical signals Musth Solid phase dynamic extraction (SPDE)
Urine samples were supplied by Disney’s Animal Kingdom, Indianapolis Zoo, Jacksonville Zoo, Knoxville Zoo, Louisville Zoo, Maryland Zoo, Memphis Zoo, Miami Metro Zoo, Nashville Zoo, Riddle’s Elephant and Wildlife Sanctuary, Six Flags Marine World, Seneca Park Zoo, and Toledo Zoo. Expertise and assistance in obtaining bacterial cultures and urinalyses were provided by Drs. Konnie Plumlee and Carl Fulton. Valuable suggestions were made by Heidi Riddle (Riddle’s Elephant and Wildlife Sanctuary). John Christie and Ben Davis carried out some preliminary experiments. We thank Hendrix College for financial support via the Odyssey Program. Additional funding in the early stages of this research was provided by the U.S. National Science Foundation (Award Nos. 02-17062, -17068 and -16862 to B.A.S., T.E.G. and the late L.E.L. Rasmussen, respectively). T.E.G. thanks John and Laura Byrd for their generous research support.
- Albone, E. S. 1984. Mammalian semiochemistry. Wiley-Interscience, New York.Google Scholar
- Albone, E. S., Gosden, P. E., and Ware, G. C. 1977. Bacteria as a source of chemical signals in mammals, pp 35–43, in D. Müller-Schwarze and M. M. Mozell (eds.), Chemical signals in vertebrates. Plenum Press, New York.Google Scholar
- Burger, B. V. 2005. Mammalian semiochemicals, pp 231–278, in S. Schulz (ed.), The chemistry of pheromones and other semiochemicals II (topics in current chemistry 240). Springer-Verlag, Heidelberg.Google Scholar
- Goodwin, T. E., Rasmussen, L. E. L., Schulte, B. A., Brown, P. A., Davis, B. L., Dill, W. M., Dowdy, N. C., Hicks, A. R., Morshedi, R. G., Mwanza, D., and Loizi, H. 2005. Chemical analysis of preovulatory female African elephant urine: a search for putative pheromones, pp 128–139, in R. T. Mason, M. P. LeMaster, and D. Müller-Schwarze (eds.), Chemical signals in vertebrates 10. Springer, New York.CrossRefGoogle Scholar
- Goodwin, T. E., Brown, P. A., Eggert, M. S., Evola, M. G., House, S. J., Morshedi, R. G., Weddell, M. E., Chen, C. J., Jackson, S. R., Aubut, Y., Eggert, J., Schulte, B. A., and Rasmussen, L. E. L. 2007. Use of automated solid phase dynamic extraction (SPDE)/GC-MS and novel macros in the search for African elephant pheromones, pp 25–35, in J. Hurst, R. Beynon, T. Wyatt, and C. Roberts (eds.), Chemical signals in vertebrates 11. Springer, New York.Google Scholar
- Sorensen, P. W., and Hoye, T. H. 2010. Pheromones in vertebrates, pp 225–262, in L. M. Mander, and H.-W. Liu (eds.), Comprehensive natural products chemistry II: chemistry and biology. Elsevier, Oxford.Google Scholar
- van Hoven, W., Prins, R. A., and Lankhorst, A. 1981. Fermentative digestion in the African elephant. S. Afr. J. Wildl. Res. 11:78–86.Google Scholar