ECOLOGICAL AND PHYLOGENETIC CORRELATES OF feeding habits in Neotropical pitvipers of the genus Bothrops

MARQUES, O.A.V.(1)

(1)Laboratório de Herpetologia, Instituto Butantan

The neotropicalpitviper genus Bothropsoccurs from Mexico to Argentina. Data on the feeding habits of 21 forms indicate that most Bothrops are diet generalists and show ontogenetic shift in prey types. Four species apparently became mammal specialists. Two island species have distinct diets: one in which adults feeds heavily on birds and another whose diet to be restricted to ectothermic prey. Mammal specializations may be related to life history strategies and the shifts observed in island species are a consequence of prey availability (there is no small mammals in the islands). Generalist species of Bothrops incorporate endotherms in their diets at a narrow range of sizes and drop ectotherms at variable sizes. Ontogenetic shifts from ectotherms to mammals in Bothrops isplesiomorphicand may be largely a consequence of ontogenetic shifts in body size. Caudal luring was observed in seven species and may occur in juveniles of all diet generalists. Feeding frequency is relatively low in Bothrops, perhaps due to sedentary habits and other factors related to inhabiting warmer climates. Mean relative prey size is moderate in Bothrops, although very large prey is occasionally eaten. Mammal specialists are stouter and feed on larger prey than generalists. Relative prey size decreases during ontogeny in some species. A high diversity of macrohabitatuse

occurs in Bothrops and the more arboreal the species, the more frequently it feeds on anurans. Lanceheadsoccur in several kinds of forests and open habitats and their diets seem to reflect local prey availability. Although a few apomorphiesappeared in some taxa, in general feeding habits in Bothrops are conservative, as most characters we analysed were already present in early crotalines.

CORRESPONDENCE TO:

Otavio Augusto Vuolo Marques, Avenida Vital Brazil, 1500, São Paulo, SP, CEP: 05503-900, Brasil, Email: otaviomarques@originet.com.br