Diets of two sympatric neotropical salamanders, Bolitoglossa mexicana and B-rufescens, with notes on reproduction for B-rufescens

Life-history data were collected for the tropical salamanders Bolitoglossa rufescens and B. mexicana at a site in Veracruz, Mexico. Individuals of bot h species consumed a wide range of prey taxa, but ants (Hymenoptera: Formic idae) comprised a large proportion of the diets of both species. Niche brea dth for B. rufescens was significantly narrower than B. mexicana, due, in p art, to a stronger representation of ants in the diet (importance values fo r ants: B. rufescens = 0.480, B. mexicana = 0.343). We hypothesize that thi s difference in dietary breadth is due to differences in body size and, pos sibly, microhabitat; B. rufescens is smaller and strictly arboreal while th e larger B. mexicana occupies both terrestrial and arboreal habitats. Diets also differed in size of prey; the larger species consumed significantly l arger ant prey. Although there was substantial dietary overlap in terms of the taxa of prey consumed, niche separation based on size of prey may be im portant for these two species. Due to relatively low numbers of B. mexicana in the sample, reproductive data were collected only for B. rufescens. Dev eloping follicles were visible in all female B. rufescens, but only six out of the 16 females had enlarged ova (minimum SVL of a female with enlarged ova = 24 mm). Because only two of the remaining females were smaller than 2 4 mm, we infer that most of the "nongravid" females were sexually mature. T wo out of 19 males in the sample were immature Size sexual dimorphism is mi nimal for this species. The largest five individuals that were captured wer e females, but, overall, males and females were not significantly different in size.