Effects of meal size, meal type, and body temperature on the specific dynamic action of anurans.
Specific dynamic action (SDA), the increase in metabolism stemming from meal digestion and assimilation, varies as a function of meal size, meal type, and body temperature. To test predictions of these three determinants of SDA, we quantified and compared the SDA responses of nine species of anurans, Bombina orientalis, Bufo cognatus, Ceratophrys ornata, Dyscophus antongilli, Hyla cinerea, Kassina maculata, Kassina senegalensis, Pyxicephalus adspersus, and Rana catesbeiana subjected to meal size, meal type, and body temperature treatments. Over a three to seven-fold increase in meal size, anurans experienced predicted increases in postprandial rates of oxygen consumption (VO(2)) the duration of elevated VO(2) and SDA. Meal type had a significant influence on the SDA response, as the digestion and assimilation of hard-bodied, chitinous crickets, mealworms, and superworms required 76% more energy than the digestion and assimilation of soft-bodied earthworms, waxworms, and neonate rodents. Body temperature largely effected the shape of the postprandial metabolic profile; peak VO(2) increased and the duration of the response decreased with an increase in body temperature. Variation in body temperature did not significantly alter SDA for four species, whereas both H. cinerea and R. catesbeiana experienced significant increases in SDA with body temperature. For 13 or 15 species of anurans ranging in mass from 2.4 to 270 g, SMR, postprandial peak VO(2) and SDA scaled with body mass (log-log) with mass exponents of 0.79, 0.93, and 1.05, respectively.
Secor
Stephen M
SM
Department of Biological Sciences, The University of Alabama, Box 870344, Tuscaloosa, AL 35487-0344, USA. ssecor@biology.as.ua.edu
Wooten
Jessica A
JA
Cox
Christian L
CL
D000821:Animal Feed; D000818:Animals; D001001:Anura / Q000378:metabolism*; D015992:Body Mass Index; D001831:Body Temperature / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology; D005247:Feeding Behavior / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D019518:Postprandial Period / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology