Seasonal Diet Variations of the Sand Lizard (Lacerta agilis) (Lacertidae, Reptilia) in the Northern Lower-Volga Region

The feeding of Lacerta agilis was studied by means of the content analysis of lizards' stomachs conducted in the vicinity of Saratov City from April till September 1983, 2003 and 2007. The maximum daily diet was characteristic in July and reached 2.5–2.7 g/day, while the minimum one was in April and September (1.1–1.2 g/day). The highest and lowest numbers of food objects were recorded in May and September, respectively. Insects are the basic food objects of L. agilis, their occurrence frequency being 100% during the whole active-life period. Coleoptera representatives predominated in the diet (25.4–40.5% by number, 43.5–70.9% by weight). The fractions of Lepidoptera, Hymenoptera, Diptera, etc. were somewhat lower. Well-flying and quickly-moving insects predominated in the food spectrum of L. agilis. Rather many invertebrates with cryptic colour, poisonous, stinging and badly smelt ones were frequently met among the nutrition objects. Moreover, vegetable remains (seeds, leaves, flower fragments etc.) and various small stones to act probably as gastrolytes were found in many stomachs.