Abstract

Female spotted salamanders (Ambystoma maculatum) engage in polyandrous behavior, and the motivation behind this behavior is currently unclear. Several studies suggest polyandrous mating may be driven by sperm limitation, efforts to seek higher quality mates, or instinctual drive for genetic diversity in offspring. These hypotheses make different predictions for how the probability of fatherhood should vary among males when females have varying numbers of mates. Research began with the design of a mesocosm experiment to manipulate the mating ratios of Ambystoma maculatum. Males and females were captured from the Sandy Bottom Nature Preserve (Buncombe County, North Carolina). Captured adults were divided among twelve miniature manufactured vernal pools, with each pool having one of four male:female ratios. After two weeks, adults and egg masses were collected. Adults were euthanized, as were offspring after hatching. Individuals were analyzed at 6 microsatellite loci and parentage was determined in CervusTM. Results suggest that sperm limitation is not a motivating factor for polyandry; mate quality and drive for genetic diversity are potential motivating factors; however, more data collection and analysis is needed.

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