GANDOLFI, B.M.*; BOBINO, C.; SECOR, S.M.; University of Alabama, Tuscaloosa; Stillman College, Tuscaloosa; Univesity of Alabama, Tuscaloosa : Allometric scaling of intestinal performance for colubrid snakes

Intraspecific and interspecific scaling relationships between metabolic, physiologic, and morphologic parameters and body size are well documented. Lacking although is any assessment of the allometric scaling of digestive performance. Therefore, we investigated the intraspecific and interspecific scaling of intestinal performance, quantified as small intestinal nutrient uptake capacity, for colubrid snakes. We calculated uptake capacity for the amino acids L-leucine and L-proline and of the sugar D-glucose of snakes digesting as the product of small intestinal mass and mass-specific rates of nutrient uptake measured using the everted-sleeve technique. Intestinal uptake capacity (logged) scaled with body mass (logged) intraspecifically for 24 diamondback water snakes, Nerodia rhombifer (10 � 1500 g), with mass exponents of 0.70, 0.68, and 0.87 respectively, for L-leucine, L-proline, and D-glucose. For ten species of colubrid snakes (5 – 725 g), interspecific allometries included respective mass exponents of 0.70, 0.67, and 0.72. For both data sets, scaling exponents did not differ significantly from the scaling exponents of small intestinal wet mass.