Food Habits of the Jamaican Lizard Anolis opalinus: Resource Partitioning and Seasonal Effects Examined

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Abstract
A stomach analysis of 340 lizards collected in 33 samples over 1 yr showed that A. opalinus eats arthropods, primarily ants, by number (70%). By volume, ants comprised only 12% of the food bulk, with lepidopteran larvae and orthopterans being the main food items (46%). The lizards fed predominantly on soft bodied prey, except for ants. Almost no evidence was found for food niche partitioning in the size dimorphic A. opalinus. All age and sex classes of lizards had eaten similar sized prey and prey taxa. When a significant difference was detected among classes, it was frequently the smaller lizards which had eaten the larger prey. The season had more effect on diversifying the diet than did size of the lizards'' trophic structures (i.e., mouths) or any possible feeding preferences. Niche overlap indices for prey length (0.86-0.94) and prey taxa (0.83-0.93) among all age-sex classes ran higher than those reported for a mainland anole with almost no sexual size dimorphism. Comparison of variables between the seasons (dry, Nov.-Mar.; wet, April-Oct.) showed that lizards tended to ingest about the same volume of food (.apprx. 17 mm3 of food/g of lizard body weight). Lizards ate more, but smaller, prey in the dry season and fewer, but larger, prey in the wet season. Relative fat body and liver weights were highest in the dry season and lowest in the wet season. Adult males and especially adult females experienced the greatest weight loss in these energy reserve organs, this was attributed in part to breeding activities. Coefficient of condition calculations (body weight/snout-vent length) showed no body weight loss between seasons for age-sex class of lizards. For the population, the volume of food taken across seasons appeared sufficient to increase energy reserves during the dry season and maintain body weight during the wet season.