Weight Growth of Juvenile Lizards, Anolis lineatopus, Maintained on Different Diets

Abstract

Prey digestion and body weight increase of juvenile Anolis lineatopus were studied in the laboratory. Caloric assimilation efficiency with respect to 4 prey types varied between 63% and 88%. Weight gain closely followed prey wet weight intake within a certain range of amount of food eaten, and was negatively linked to initial body weight. When food intake surpassed a certain level, weight gain no longer depended on prey intake, but was positively related to initial body weight. This suggests that when the opportunity arises, anoles feed on more prey than they can process and waste increasing amounts of the food eaten. The lizards could sustain low diets, which allowed almost no weight gain, for several weeks with no apparent losses in later growth performance under improved food conditions. They also survived a 10 d period of complete star- vation, losing about 0.6 % of body weight per day. Variation in extractable energy among prey types did not lead to different growth responses. However, two specific prey types had a comple- mentary effect in a 10 d growth experiment. Anoles gained considerably more weight from a mix- ture of these two than from single prey diets or 2-prey mixtures which included only one of the specific types. Increase of prey type diversity per se did not enhance growth.