Plant consumption in coastal populations of the lizard Tropidurus torquatus (Reptilia: Squamata: Tropiduridae): how do herbivory rates vary along their geographic range?

Abstract

Tropidurus torquatus lizards commonly consume vegetal matter as part of their diet. However, it is not known to what extent the rate of consumption of plant material varies among populations. We investigated the consumption of plant material in 10 populations of T. torquatus in eastern Brazil. In all populations, lizards consumed plant matter (especially fruits and flowers). The proportion of plant volume in the diet varied from 2.1% to 58.0% of the total volume consumed. Differences in volumetric proportion of plant material consumed did not result from lizard body size or population latitude. The volumetric proportion of plant material did not differ between sexes at each locality; however, there was a slight trend for larger lizards to consume more plant parts. The data obtained indicate that the observed interpopulational variation in plant consumption by T. torquatus results from local environmental factors, mainly the availability of plant matter.

Keywords:

• tropical lizard
• diet
• plant consumption
• geographic variation

Acknowledgements

This study is part of the “Programa de Ecologia, Conservação e Manejo de Ecossistemas do Sudeste Brasileiro”, of the research project “Ecologia geográfica das espécies de Tropidurus (Squamata: Tropiduridae) do grupo torquatus do leste e centro-oeste do Brasil”, and of the “Southeastern Brazilian Vertebrate Ecology” Project (Laboratory of Vertebrate Ecology), Departamento de Ecologia, Instituto de Biologia, Universidade do Estado do Rio de Janeiro. We thank Davor Vrcibradic, Mônica Cunha-Barros, Conrado A. B. Galdino, Vanderlaine A. Menezes, Angélica F. Fontes and Fabio H. Hatano for field assistance; and Paulo Passos for help with the map. D. Vrcibradic kindly revised a first draft of the manuscript and offered helpful suggestions. This study was supported by research grants from the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) to M.C. Kiefer (processes 146442/1999-7 and 150353/2003-0), C.F.D. Rocha (processes 307653/2003-0 and 476684/2008-0) and M. Van Sluys (process 307773/2008-6), and from Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) to M.C. Kiefer (process E-26/171.168/2006) and to C.F.D. Rocha through the “Cientistas do Nosso Estado” Programme (process E-26/102.404.2009). This study was partially supported by the Programa de Pesquisas Ecológicas de Longa Duração (PELD / CNPq – Site 5 Restinga de Jurubatiba) and from the Programa de Pós-Graduação em Ecologia, Instituto de Biologia, Universidade Estadual de Campinas (Unicamp). During this study C.C. Siqueira received a graduate fellowship from FAPERJ. Permit for collecting the lizards was provided by IBAMA (process 2001.03486/99.85).