GILLEM, A.D.*; FINKLER, M.S.; Indiana Univ. Kokomo: Sex-related differences in stored energy reserves in spring-breeding spotted salamanders (Ambystoma maculatum).

The energetic cost of reproduction for female mole salamanders may be considerably higher for female mole salamanders than for males, not only because of a difference in the amount of energy invested in the gametes but from indirect costs associated with maintenance of support tissues, elevated energetic cost of locomotion, etc. Here, we examined how differences in these reproductive costs might impact stored energy reserves (fat and glycogen) in female and male spotted salamanders (Ambystoma maculatum) from a population in North-Central Indiana. Although males tended to be smaller, they had proportionately larger liver masses and a greater solid fraction to that liver mass. Non-polar lipid and glycogen contents of the carcasses were similar for males and females, but males had greater amounts of these energy substrates in their livers than did females. These findings suggest a greater depletion of stored energy reserves in females to fuel a higher energetic cost of reproduction. This differential reduction in energy reserves between the sexes, in turn, could in part account for observed differences in growth rates, fecundity, and survivorship in Ambystomid salamanders.