Abstract

Reproduction and post-metamorphic growth of the American toad (Anaxyrus americanus) were examined in specimens from agricultural fields in south central Pennsylvania. Males were most fertile during spring and early summer. Females were gravid from April to June and in October prior to brumation. Clutch and body size relationships were indicative of a K strategy, perhaps reflecting a population at carrying capacity. Sexual maturity was reached at postmetamorphic ages of approximately two years in males (min = 56.7 mm SVL) and three years in females (min = 68.9 mm SVL). Later-season metamorphoslings of both sexes would not have bred for the first time until nearly one year later. Mean adult body size was smaller in males (mean = 69.4 mm SVL) than in females (mean = 81.5 mm SVL). Life history traits examined in this study reflect responses of both northern and southern populations and quantify effects of site-specific conditions on reproductive relationships.

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