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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Life Histories
ENERGETIC COSTS OF PRECOPULATORY MATE GUARDING IN TWO FRESHWATER AMPHIPOD SPECIES.
R.D. Cothran. Department of Zoology, University of Oklahoma, Norman, Oklahoma, USA 73019
The length of precopulatory mate guarding varies among habitats within the Hyalella azteca species complex. Precopulatory mate guarding may reduce foraging efficiency and increase energy use thus imposing energetic costs on individuals in precopula. These energetic costs may affect the amount of time an individual must spend out of mating (TOM) to replenish spent energy reserves, which in turn may alter operational sex ratios. Because operational sex ratios often influence the opportunity for sexual selection, variation in TOM across habitats may result in differences among populations in the strength of sexual selection. In this study I compared energy reserves for paired and single males for two species within the Hyalella azteca species complex. Paired and single males were collected at two localities in central Oklahoma. Head length was measured for each individual and used as a covariate in all analyses. Glycogen content was determined using spectrophotometric methods. For both species, glycogen levels did not differ between paired and single males. However, there was large variation in glycogen levels for paired males in the species with a lengthy precopulatory mate guarding phase, which may have reduced my ability to detect a difference between the two groups.
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