Are diet diversity metrics influenced more by rainfall or by temperature in an Afrotropical Scincid Lizard?

Abstract

AbstractThe ecology and activity patterns of many tropical vertebrate species are heavily influenced by the seasonal alternance of dry and wet periods. However, the effects of the dry–wet seasonal alternance on feeding habits of tropical vertebrates are poorly known. In this paper, the monthly variations in the diet of the scincid lizard Trachylepis quinquetaeniata were studied, by faecal pellet analysis, in a sandy beach area of southern Togo (West Africa) in relation to both rainfall and temperature‐related variables. The diet was basically insectivorous, with five prey types (Coleoptera adults and larvae, Lepidoptera adults and larvae and Formicidae) being dominant in the pellets. Prey composition was similar between sexes, but varied considerably across months. There was a positive correlation between mean monthly rainfall and number of prey categories eaten in each month. General linear models (GLM) showed that both Simpson and Shannon indices increased with the monthly number of rainy days. GLM also showed that rainfall regime influenced the frequency of eaten Coleoptera adults and larvae and of Lepidoptera adults and larvae, with no effect on Formicoidea. Our study confirms that dietary patterns of tropical lizards are influenced by the wet‐dry‐seasonal alternance, and that both the taxonomic composition of the diet and the dietary diversity metrics are significantly affected. We also demonstrated that rainfall is more important than temperature in determining the dietary variations, and that, among the rainfall‐linked variables, it is the monthly number of rainy days that represents the most important variable.