白頷樹蛙蝌蚪溫度生理學之研究

• Main Author: 吳華蓉
• Other Authors: 王瑋龍
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/17673857968053496705

碩士 === 國立彰化師範大學 === 生物技術研究所 === 92 === Abstract I assessed the metabolism compensation, temperature tolerance, and behavioral thermoregulation of Polypedates megacephalus tadpoles that live in the container habitats from Baque terrace. I collected foam nests from the field, hatched them in laboratory, and reared each halves of the tadpoles in tanks that contained either 140 L or 15 L of water outdoor. I monitored the daily water temperature of containers using a data-logger. To assess metabolic compensation, I randomly selected 60 tadpoles from each tank, acclimated 30 tadpoles each in either 32 or 22 ℃, and measured oxygen consumption of tadpoles in either 22 ℃, 27 ℃ or 32 ℃ 10 days after. I assessed the thermal tolerance of tadpoles by measuring the critical thermal maxima of 12 tadpoles each from large and smaller tanks. We determined the thermal selection of 30 tadpoles each from large and small tanks using an aquatic thermal gradient. Results showed that water temperature of large and small tanks varied with maximal temperature reached 30.4 and 29.8 ℃, respectively. The thermal stratification of water in the large tank (2.26 ℃) was greater than that of small tank (0.7 ℃). The oxygen consumption of tadpoles that acclimated in 22 ℃ was higher than that of in 32 ℃. Tadpoles in both tanks could tolerate water temperature over 40 ℃, and the critical thermal maxima were not differed between tadpoles from large and small tanks. In addition, the mean and coefficient of variation of preferred temperatures were not differed between tadpoles from large and small tanks. The results showed that even though tadpoles were reared in tanks that contained water 10 times differences in volume, but the differences in water volume may not large enough to elicit any significant physiological adjustments of tadpoles. This may explain why there were no differences in thermal tolerance and temperature preferences between tadpoles in different tanks. Polypedates megacephalus tadpoles could experience relatively large fluctuations in body temperature (up to 8.4 ℃) during the development, thus, tadpoles are most likely to evolve metabolic compensation to maintain activity levels under different thermal regimes. The high thermal tolerance of tadpoles enables them to cope with the high water temperature in the tanks which heat up rather quickly by solar radiation. Results showed that tadpoles thermoregulate behaviorally, and the coefficient of variation of temperature selected tadpoles suggests tadpoles are strong thermal selector. In Bagua terrace, some frog populations of P. megacephalus also breed in larger water tanks that exhibited thermal stratification of water, thus, from evolutionary point of view, a strong thermal selector would enable the tadpoles to select water at the temperatures they prefer in order to maximize their growth and development.