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

Abstract

Life-history data were collected for the tropical salamanders Bolitoglossa rufescens and B. mexicana at a site in Veracruz, Mexico. Individuals of both species consumed a wide range of prey taxa, but ants (Hymenoptera: Formicidae) comprised a large proportion of the diets of both species. Niche breadth for B. rufescens was significantly narrower than B. mexicana, due, in part, to a stronger representation of ants in the diet (importance values for ants: B. rufescens = 0.480, B. mexicana = 0.343). We hypothesize that this difference in dietary breadth is due to differences in body size and, possibly, microhabitat; B. rufescens is smaller and strictly arboreal while the larger B. mexicana occupies both terrestrial and arboreal habitats. Diets also differed in size of prey; the larger species consumed significantly larger 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 important for these two species. Due to relatively low numbers of B. mexicana in the sample, reproductive data were collected only for B. rufescens. Developing 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 24 mm, we infer that most of the 'nongravid' females were sexually mature. Two out of 19 males in the sample were immature. Size sexual dimorphism is minimal for this species. The largest five individuals that were captured were females, but, overall, males and females were not significantly different in size.

Department(s)

Biology

Document Type

Article

DOI

https://doi.org/10.2307/1565576

Publication Date

1-1-1999

Journal Title

Journal of Herpetology

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