Abstract # 110:

Scheduled for Friday, June 22, 2007 02:00 PM-02:15 PM: Session 12 (North Main Hall E) Oral Presentation

Testis Size and Social System in Strepsirhines

K. Treatman-Clark
IDPAS, Stony Brook University, Stony Brook, NY 11794, USA
     This study re-analyzed the relationship between testis volume and mating system in strepsirhines using phylogenetic statistical techniques to account for the influence of evolutionary history on testis size. Additionally, this study assessed whether large testes and large indices of sexual size dimorphism constitute alternative mating strategies in strepsirhines depending on whether the majority of mating competition takes place before or after copulation. Testis volume and sexual size dimorphism were measured in 34 captive and wild reproductively active strepsirhine taxa from the Duke Primate Center and Ranomafana National Park, Madagascar. Least-squares regression of testis volume on body mass was used to compare relative testis sizes among taxa with different mating systems and the program MacClade was used to reconstruct the evolution of testis volume, body size dimorphism, and social system in strepsirhines. Socially pair-bonded strepsirhines all fell on or below a regression line predicting testis volume for body mass, and the MacClade concentrated changes test [a=0.05] indicated that the evolution of testis size was not random with regard to mating system; increase in testis size was always associated with the transition to a multi-male mating system. However, a Pearson product-moment correlation analysis of residual testis size showed that body mass dimorphism is not associated with testis size [r(26)=0.10, p=0.624] indicating that there is no trade-off between pre-copulation physical competition and post-copulation sperm competition in strepsirhines.