Thermal Physiology and Reproductive Phenology of Buergeria japonica (Rhacophoridae) Breeding in a Stream and a Geothermal Hotspring in Taiwan(Ecology)(<SPECIAL ISSUE>Origin and evolution of chordates)

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We compared the reproductive phenology and tadpole thermal physiology of two populations of Buergeria japonica in Taiwan. The population in Jentse breeds in a geothermal hot spring whose water is a warm, over 35℃ year-round, whereas the population in Chukou breeds in a stream whose water temperature is closely correlated with fluctuations in air temperature and averages 23℃. 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℃ attained larger sizes than tadpoles from Chukou that reared at 32℃, whereas tadpoles from both sites attained similar body size when reared at 22℃. Chukou tadpoles reared at 40℃ died within 1-2 d, whereas Jentse tadpoles survived for 9 d at 40℃. All tadpoles tolerated heat well, but Jentse tadpoles had higher critical thermal maxima (CTMax) than Chukou tadpoles. Tadpoles from Jentse showed no metabolic compensation but those from Chukou showed an "inverse" metabolic compensation. Results suggest that B. japonica that breed in the geothermal hot spring has a prolonged breeding season, high growth rates and the reduction or absence of intra- and inter-specific competition. Evolution of a high level of heat tolerance and, possibly, behavioral temperature selection, enable tadpoles in the hotsprings to offset the thermal stress imposed by warm water.
2001-05-20