Abstract # 148:

Scheduled for Friday, August 18, 2006 03:25 PM-03:45 PM: Session 15 (Regency East #3) Oral Presentation

Heterogeneity of reproductive aging in free-ranging, female rhesus macaques

R. Johnson1 and E. Kapsalis2
1Mannheimer Foundation, Homestead, FL 33034, USA, 2University of Miami, Division of Veterinary Resources, Miami, FL
     Here we examine inter-individual variability in fertility as a function of age among free-ranging female rhesus monkeys (Macaca mulatta). Our study site, Raccoon Key, is an island, about 81 hectares in area, situated in the Gulf of Mexico. Our data were collected from 1992-1999, the last seven years a large population of provisioned macaques were resident on the island. We have previously demonstrated that the birth rate realized by the Raccoon rhesus in aggregate declined incrementally with female age beginning by at least the age of 9 years. In this paper, we examine females that reproduce annually (producers) or, alternatively, fail to reproduce (non-producers) over four successive birth seasons from ages 8 – 24 years. If all females experience an incremental loss of reproductive capacity with each year of age, the observed number of non-producers would increase, and the number of producers would decrease with female age, but not above chance levels. However, both occurred at frequencies greater than expected by chance alone indicating there was strong heterogeneity in female fertility. A sudden catastrophic loss of fertility by a minority of females each year was most consistent with our data, and this outcome is expected on the basis of the evolutionary theory of aging.