Evol Ecol Res 4: 577-585 (2002)     Full PDF if your library subscribes.

Dynamics of testes size compensates for variation in male body size

Sharon T. Pochron* and Patricia C. Wright

Department of Anthropology, State University of New York at Stony Brook, Stony Brook, NY 11794, USA

Author to whom all correspondence should be addressed.
e-mail: spochron@ms.cc.sunysb.edu


Lemurs demonstrate various mating systems but paradoxically lack sexual dimorphism. No convincing mechanism can explain the lack of large-bodied males. In mammals, testicle size correlates with body size; here, we examine how testicles vary relative to body weight within a population of Malagasy lemurs. We show that the significant positive relationship between body size and testicles in non-breeding seasons dissipates in breeding seasons because the testicles of lighter males grow more and match heavier males’ testicles. Low and unpredictable plant productivity characterizes Madagascar’s ecosystems, and natural selection may favour testicle–body size decoupling during challenging years, inhibiting the evolution of dimorphic males.

Keywords: intrasexual competition, lemurs, mating systems, sexual dimorphism, sperm competition.

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        © 2002 Sharon T. Pochron. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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