Sexual dimorphism in development and venom production of the insular threatened pit viper Bothrops insularism (Serpentes: Viperidae) of Queimada Grande Island, Brazil

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S.R. Travaglia-Cardoso
A. Zelanis
M.de.F.D. Furtado

Abstract

Bothrops insularis is a threatened snake endemic to Queimada Grande Island, southern coast of São Paulo, Brazil, and the occurrence of sexual abnormalities in females (females with functional ovaries and rudimentary hemipenis) has been reported in this population. To date there are few data regarding developmental features of this particular species. The aim of this study was to follow some developmental features in specimens maintained in captivity for seven years in the Herpetology Laboratory at Instituto Butantan, São Paulo, Brazil. We verified a pronounced sexual dimorphism in development and venom production in the specimens analyzed. In this regard, females showed greater length, mass and amount of venom in comparison to males. Our results suggest a possible niche partitioning between the sexes that reduces (or minimizes) intraspecific disharmonic interactions (eg. competition) on their small living area (Queimada Grande Island). Taken together, our data suggest that males and females probably are divergent in their diets, with females feeding preferentially on endothermic prey (such as migratory birds), while males maintain the juvenile diet (with the major items being ectothermic prey).

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Author Biographies

S.R. Travaglia-Cardoso

ilvia R. Travaglia-Cardoso is a researcher from the Herpetology Laboratory, at Butantan Institute, São Paulo, Brazil. She is currently a PhD student in USP. Her main research field is the reproduction and maintenance of snakes in captivity.

A. Zelanis

André Zelanis is a PhD student at Center for Applied Toxinology (CAT/CEPID) at Butantan Institute, São Paulo, Brazil. His main research field is the variability found in the venom proteome of South American snakes.

M.de.F.D. Furtado

Maria de Fátima Domingues Furtado is a researcher from the Herpetology Laboratory, at Butantan Institute, São Paulo, Brazil. She has performed her PhD in Physiology at Biosciences Institute at São Paulo University. Her main research is the venoms of snakes and the biological variability.