Resumo

GADSDEN, Héctor  e  PALACIOS-ORONA, Luis. Composición de dieta de Cnemidophorus tigirs marimoratus (Sauria: Teiidae) en dunas del centro del Desierto Chihuauhense. Acta Zool. Mex [online]. 2000, n.79, pp.61-76. ISSN 2448-8445.

In 1990 we studied the seasonal feeding patterns of the Western Marbled Whiptail (Cnemidophorus tigris marmoratus) in sand dunes of central Chihuahuan Desert, México (26° 50' N, 103° 49' W). The stomachs of 35 males and 20 females were examined and the importance value (relative abundance + relative volume + prey constancy), Shannon-Wiener diversity index and intersexual niche overlap (summer and autumn) of prey items were determined. Adult Isoptera were the most important prey during the three seasons studied (I.V. = 38.8 %, both sexes). Other important food items were Lepidoptera (larvae), Dictyoptera (nymphs), Coleoptera (adults) and Araneae. This lizard showed an average H' = 1.1 and H'v = 2.7 and thus is considered to have a generalist diet. The intersexual niche overlap was large in summer and autumn (O_jk = 0.95). There were no differences in prey size between the sexes. The coefficient of variation for prey length (CV-PL) was larger in males, whereas it was smaller for snout-vent length (CV-SVL) in males. Males were significantly larger and heavier than females. The observed differences in body size between sexes might be related to differences in finite rate of annual survival among them.

Palavras-chave : Chihuahuan Desert; lizards; trophic diversity; diet overlap; sexual dimorphism.

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