Discrimination of anxiety- versus panic-like behavior in the wall lizard Tropidurus oreadicus

A behavioral test battery is proposed for wall lizards (Tropidurus oreadicus) that consists of inducing tonic immobility (TI) followed by post-TI behavioral scoring. After the induction of TI, the usual behavioral sequence was flight followed by freezing and tongue-flicking and/or thigmotaxis, with flight being more probable than freezing. These sequences were not observed after restraint in a normal upward position (which induced freezing but not TI) or after handling (which increased the probability of tongue-flicking). Alprazolam and imipramine selectively decreased the duration of TI as well as the following flight and freezing behavior. Tongue-flicking was increased by diazepam and alprazolam, whereas fluoxetine decreased it. Finally, thigmotaxis was reduced by diazepam, alprazolam, and imipramine but increased by fluoxetine. These results suggest that panic and anxiety can be discriminated pharmacologically in wall lizards...

Feeding ecology of the lizard Tropidurus oreadicus Rodrigues 1987 (Tropiduridae) at Serra dos Carajás, Pará state, northern Brazil

Tropidurus species commonly prey on arthropods, but they may also feed on vertebrates and plant material. The lizard Tropidurus oreadicus (Tropiduridae) is common in open vegetation habitats and generally has sexual dimorphism. In this study we analyzed the diet of T. oreadicus at Serra dos Carajás, Pará, in the north of Brazil. Snout-vent length (SVL) and jaw width (JW) were taken for 34 lizards. There was a significant difference in SVL and in JW, with males being larger than females. All lizards analyzed contained food in their stomachs. The diet of T. oreadicus at Serra dos Carajás was characterized by the consumption of a relative wide spectrum of food item categories (21 types of items), consisting of arthropods, part of one vertebrate and plant material, which characterizes the diet of a generalist predator. Volumetrically, the most important items in the diet of both sexes of T. oreadicus were flowers (M = 61.7 percent; F = 33 percent) and orthopterans (M = 1.7 percent; F = 3.5 percent). Ants were the most frequently consumed (100 percent for both sexes) and the most numerous (M = 94.5 percent; F = 89.4 percent) food item. Flowers also were frequently consumed (M = 91.7 percent; F = 54.5 percent), with their relative consumption differing significantly between sexes. There was not a significant sexual difference in prey volume, neither in number of preys per stomach, nor in type of prey ingested. There was no relationship between lizard jaw width and the mean volume of prey. The data showed that T. oreadicus is a relatively generalist lizard in terms of diet and that consumes large volumes of plant material, especially flowers of one species of genus Cassia.

Espécies de Tropidurus comumente predam artrópodos, mas eles também podem consumir vertebrados e material vegetal. O lagarto Tropidurus oreadicus (Tropiduridae) é comum em habitats de vegetação aberta e geralmente possui dimorfismo sexual. Neste estudo, analisamos a dieta de T. oreadicus na Serra dos Carajás, Pará, Norte do Brazil. O comprimento rostro-cloacal (CRC) e a largura da mandíbula (LM) foram medidos em 34 lagartos. Houve diferença significativa em termos do CRC e da LM, com os machos sendo maiores do que as fêmeas. Todos os lagartos continham alimento em seus estômagos. A dieta de T. oreadicus da Serra dos Carajás foi caracterizada pelo consumo de uma grande variedade de categorias de itens alimentares (21 tipos de itens), consistindo de artrópodes, de parte de um vertebrado e de material vegetal, o que caracteriza a dieta de um predador generalista. Volumetricamente, os itens mais importantes na dieta de ambos os sexos de T. oreadicus foram flores (M = 61,7 por cento; F = 33 por cento) e ortópteros (M = 1,7 por cento; F = 3,5 por cento). Formigas foram os itens mais freqüentemente consumidos (100 por cento para ambos os sexos) e os mais numerosos (M = 94,5 por cento; F = 89,4 por cento). Flores também foram freqüentemente consumidas (M = 91,7 por cento; F = 54,5 por cento), diferindo significativamente em consumo entre os sexos. Não houve diferenças sexuais em volume, em número, nem em tipos de presas ingeridas. Não houve relação entre largura da mandíbula dos lagartos e a média do volume de presas. Os dados mostraram que T. oreadicus é um lagarto relativamente generalista em termos de dieta e que consome grande volume de material vegetal, especialmente flores de uma espécie do gênero Cassia.