TREE LIZARD DISTRIBUTION AND MATING SYSTEM - THE INFLUENCE OF HABITAT AND FOOD RESOURCES

Examined the distribution of the insectivorous Urosaurus ornatus (Iguanidae) in the Sonoran Desert of Arizona. In dry washes tree lizards occupied mesquite Prosopis juliflora trees, whereas in flatland habitat they lived in mesquite trees and other sites (dead mesquite and saguaro cactus Carnegeia gigantea). Lizards were more abundant in dry washes. The mating system was variable and a greater proportion of males were polygynous in wash (33-67%) compared with flatland (7-33%) habitat. In the flatland, home ranges in which females oviposited could be distinguished from vacant sites by soil hardness, shrub cover, and the presence of wood rat Neotoma albigula nests. Arthropod abundance did not differ between female home ranges and nearest vacant site nor between habitats and among male territories. Therefore, food resource distribution does not appear to be a determinant of either female distribution or territory quality in male tree lizards. -from Authors