Resumen

GADSDEN, Héctor  y  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.

Palabras llave : Chihuahuan Desert; lizards; trophic diversity; diet overlap; sexual dimorphism.

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