Digestive paramenters of the eastern collared lizard, crotaphytus collaris.

Abstract

Digestive physiolo is important because animals can only obtain calories needed for growth, maintenance, and reproduction by feeding. The purpose of my study was to examine the digestive efficiency (DE) and food passage time for the Eastern Collared Lizard, Crotaphytus collaris, when fed different meals: neonatal mouse (Mus museu/us), two masses of cricket (Acheta domestica), and two masses of mealworm larva (Tenebrio mo/itor). The mass of food ingested and defecated by 13 C. collaris during five four-day feeding trials was recorded. Different colored beads were fed to the lizards each day of the feeding trials to estimate food passage times. Fifteen neonatal mice, 19 crickets, and 10 mealworms were chosen as food samples. Linear regression equations were made by regressing food sample wet mass with dry mass and dry mass with calories. The mass of meals ingested was converted to calories using these equations. Fecal calories were determined by bomb calorimetry. Percent DE was calculated using the equation: (Calories Consumed -Fecal Calories) / Calories Consumed x 100. An Analysis of Covariance (ANCOVA) was performed, followed by a multiple comparison test. It was determined that meal size did not affect the DE of C. collaris, but meal type did. The DEs of the 3.5% body mass-sized mealworn and cricket meals were significantly different (P = 0.0023), as was the DEs of the 1.0% body mass-sized mealwonn and cricket meals (P = 0.0020). There were no significant differences (P> 0.05) among the food passage times of C. collaris when fed the four insect meals. The neonatal mouse meal took significantly longer (P<0.05) to pass than the insect meals. In summary, meal size did not affect the DE or food passage time of C. collaris, but meal type did affect its DE and food passage time.