The thermal environment of arboreal pools and its effects on the metabolism of the arboreal, oophagous tadpoles of a Taiwanese tree frog, Chirixalus eiffingeri (Anura : Rhacophoridae)

We have studied seasonal and diurnal fluctuations of water temperature in b amboo stumps and the effect of temperature on the energy metabolism of arbo real, oophagous tadpoles of Chirixalus eiffingeri. We collected tadpoles (G osner stage 28-29) in February and August from Chitou, Taiwan and acclimate d them to 12 and 22 degreesC. Using a closed system, we measured tadpole ox ygen consumption ((V)over dot O-2) at 12, 17 and 22 degreesC. The water tem perature was lowest in February (11-13 degreesC), increased rapidly during March and April and was highest from May to August (20-24 degreesC). Diel f luctuations in the temperature of the pools of water in bamboo stumps mirro red fluctuations in air temperature. Tadpoles collected in February and Aug ust exhibited metabolic compensation in that tadpoles acclimated at 12 degr eesC had significantly higher lie, than those acclimated at 22 degreesC. Th ere are at least two possible explanations for the presence of metabolic co mpensation in C. eiffingeri tadpoles. Firstly, the larval period of C. eiff ingeri ranges from 40 to 78 days, a tadpole could experience relatively lar ge fluctuations in body temperature (up to 10 degreesC) during the developm ent. As a result, C. eiffingeri tadpoles most likely evolved metabolic comp ensation to maintain activity levels under different thermal environments. Secondly, because arboreal pools are small, thermally unstratified, aquatic microhabitats, tadpoles are unable to behaviorally select preferred temper atures. As a result, metabolic compensation allows tadpoles to regulate the ir physiological functions. (C) 2001 Elsevier Science Inc. All rights reser ved.