Meeting Abstract

38.2  Friday, Jan. 4  Physiological dimorphisms in pre- and post-reproductive spotted salamanders: endocrine and mitochondrial density differences FINKLER, M.S.*; WILLIAMS, M.K.; MCELVEEN, R.T.; Indiana Univ. Kokomo; Indiana Univ. Kokomo; Indiana Univ. Kokomo mfinkler@iuk.edu

We investigated potential differences in circulating levels of corticosterone and thyroxine and in mitochondrial densities in various tissues of male and female spotted salamanders (Ambystoma maculatum) both before and after breeding. Pre-breeding animals had greater levels of both hormones compared to post-breeding animals, but there was no difference between the sexes in the plasma concentration of either hormone. In contrast, females had greater mitochondrial densities in their livers than did males, but mitochondrial density did not differ with reproductive condition. These differences in hormone levels, as well as differences in mitochondrial density, may account for previously observed differences in metabolic rate and biochemical composition between the sexes during reproduction.