Thermal physiology and reproductive phenology of Buergeria japonica (Rhacophoridae) breeding in a stream and a geothermal hotspring in Taiwan

We compared the reproductive phenology and tadpole thermal physiology of tw o populations of Buergeria japonica in Taiwan. The population in Jentse bre eds in a geothermal hot spring whose water is a warm, over 35 degreesC year -round, whereas the population in Chukou breeds in a stream whose water tem perature is closely correlated with fluctuations in air temperature and ave rages 23 degreesC. The B. japonica population in Jentse breeds year-round, but the Chukou population breeds only from March to October. Tadpoles from Jentse that reared at 32 degreesC attained larger sizes than tadpoles from Chukou that reared at 32 degreesC, whereas tadpoles from both sites attaine d similar body size when reared at 22 degreesC. Chukou tadpoles reared at 4 0 degreesC died within 1-2 d, whereas Jentse tadpoles survived for 9 d at 4 0 degreesC. All tadpoles tolerated heat well, but Jentse tadpoles had highe r critical thermal maxima (CTMax) than Chukou tadpoles. Tadpoles from Jents e showed no metabolic compensation but those from Chukou showed an "inverse " metabolic compensation. Results suggest that B. japonica that breed in th e geothermal hot spring has a prolonged breeding season, high growth rates and the reduction or absence of intra- and inter-specific competition. Evol ution of a high level of heat tolerance and, possibly, behavioral temperatu re selection, enable tadpoles in the hotsprings to offset the thermal stres s imposed by warm water.