Social, Ecological and Endocrine Influences on Female Relationships in Blue Monkeys (Cercopithecus mitis stuhlmanni)

As a graduate student I examined female sexual behavior in the Kakamega Forest blue monkeys under uni- and multi-male mating conditions.  To evaluate the hypothesis that female sexual behavior functions to manipulate paternity assessment when multiple unfamiliar males are present, I developed a technique for extracting ovarian hormones from fecal samples and determined the relationship between behavior and reproductive physiology under different mating conditions.  The results of my study showed that females often mate at times when conception is highly unlikely or impossible:  females were sexually active for periods well beyond the time surrounding ovulation, and they also mated during pregnancy and prior to the onset of ovarian cycling.  Moreover, following a resident-male turnover that occurred during my study, several females rapidly became sexually active even though they showed no sign of ovarian function.  However, while females did have longer sexually active periods when multiple males were in their group, they were no more likely to mate during pregnancy or prior to the onset of ovarian cycling under uni- vs. multi-male mating conditions.

Endocrine profiles for both pregnant and acyclic females consistently revealed increases in estrogen levels that were accompanied by sexual behavior at certain times when females were not otherwise ready to conceive because of the continued maintenance of high progesterone levels which would have blocked ovulation.  Potentially, the increase in estrogen levels at these times when females are not otherwise ready to conceive is part of an adaptive mechanism through which the likelihood of mating is increased, irrespective of the number or familiarity of males who are present.  Alternatively, the elevation in estrogen levels at certain points during gestation and acyclic periods simply may be a side effect of the biological constraints of reproduction. 

To further evaluate the role of progesterone in regulating sexual behavior as well as reproductive function in nonhuman primates I am conducting more detailed physiological studies as a postdoctoral fellow at the Yerkes National Primate Research Center.  By systematically manipulating the timing of exposure and the relative dose of progesterone in comparison to estradiol, I hope to determine whether the endocrine profiles I discovered in the Kakamega Forest blue monkeys could in fact serve as a mechanism for promoting sexual behavior at times when females are not otherwise ready to conceive.

Karen became a Postdoctoral Fellow at Yerkes National Primate Center;
Karen then received a Master's of Public Health and now works in public health research.


Publications based on doctoral research:

• Pazol, K.P. & Cords, M. 2005. Seasonal variation in feeding behavior, competition and female social relationships in a forest-dwelling guenon, the blue monkey (Cercopithecus mitis stuhlmanni), in the Kakamega Forest, Kenya. Behavioural Ecology and Sociobiology 58: 566-577
• Pazol, K.P. 2003. Mating in the kakamega forest blue monkeys (Cercopithecus mitis): Does female sexual behavior function to manipulate paternity assessment? Behaviour 140: 473-499.
• Pazol, K., Carlson, A.A., Ziegler, T.E. 2002. Female reproductive endocrinology in wild blue monkeys: a preliminary assessment and discussion of potential adaptive functions. In: Glenn, ME & Cords, M, eds. The Guenons: Diversity and Adaptation in African Monkeys.  New York: Kluwer Academic/Plenum Publishers. pp. 217-232