WOOTEN, J.A.*; SECOR, S.M.; University of Alabama, Tuscaloosa; University of Alabama, Tuscaloosa: Determinants of the specific dynamic action for anurans

Specific dynamic action (SDA) is characterized by an increase in metabolic rate that accompanies meal digestion and assimilation. Given its interplay with digestive physiology and its importance to energy budgets, we undertook a comparative study of anuran SDA. For the green treefrog (Hyla cinerea), an increase in meal size generated a larger postfeeding metabolic response and overall SDA. In addition to influencing metabolic rates, body temperature significantly effected SDA independent of meal size. SDA was similarly impacted by meal type; the cost of digesting superworms was significantly greater than the cost of digesting earthworms. For 19 species of bufonids and 11 species of hylids the digestion of cricket meals equaling 10% of body mass at 30&degC generated 3.6 and 2.9-fold increases, respectively, in metabolic rates, with total SDA equaling 10 to 30% of ingested energy. For 40 species of anurans representing eight families (Bombinatoridae, Bufonidae, Dendrobatidae, Hylidae, Hyperoliidae, Microhylidae, Ranidae, and Rhacophoridae), SMR, peak VO₂ during digestion, and SDA (kJ) scaled (log-log) to body mass (1.2 � 153 g) with mass exponents of 0.73, 0.85, and 1.04, respectively.