LTREB: Fitness Consequences of Pleiotropic Androgen Effects in Free-Living Mammals

Michigan State University, East Lansing MI

Investigators

Abstract

Little is known about the effects of prenatal hormone exposure on offspring fitness in natural populations. Therefore, the primary goal of this project is to determine how brief exposure to varying concentrations of male hormones (androgens) before birth influences subsequent behavior, survival and reproduction in free-living mammals, using spotted hyenas in Kenya as model animals. Preliminary data suggest that androgens, like testosterone, may have opposing effects in female hyenas such that aggressiveness is enhanced while fertility is compromised. In this study, investigators will follow into adulthood cubs born to mothers with known concentrations of androgens during late pregnancy, and manipulate androgen concentrations to which young hyenas are exposed in the womb, to determine how long androgen-mediated effects endure, and whether prenatal hormone exposure influences survival and reproduction. This work will provide a novel and comprehensive picture of both immediate and long-term effects of early androgen exposure as the investigators follow focal hyenas from birth to adulthood, and closely monitor survival and reproduction in multiple generations. The results of this study will be important, not only for understanding the unique traits of spotted hyenas, but also for understanding more broadly the role of prenatal hormone exposure in the generation of natural variation in morphology and behavior, and the role of opposing androgen effects in the evolution of mammalian life histories. This research offers unique and highly valuable training opportunities for American students in an international environment. The investigators will also continue training Kenyan graduate students, supporting Masai students in rural elementary schools, working closely with the public media, maintaining their educational website, and giving many lectures each year to lay audiences. In addition, they will make core data from this long-term project available to other scientists and the general public through two web portals.