アサヒガニ幼生の生残,摂餌および発生に及ぼす水温の影響

抄録

In order to examine temperature effects on several larval characters, zoeas of Ranina ranina were reared under 5 temperature levels ranging 17 to 33°C. Survival decreased at lower temperatures and optimum range for the survival seemed to become narrower in later instars. The molting depended significantly on the temperature, and molting intervals increased exponential-ly at lower temperatures. The optimum temperature was 25 to 29°C for growth and morphogenesis during all zoeal instars. The growth decreased and morphogenesis delayed at lower and higher temperatures out of optimum range. Food intake tended to increase at higher tem-perature at instars I to V but was the maximum at 25°C at instar VII. At higher temperature, reduction of growth and delay of morphogenesis were observed, in spite of a large amount of food intake in early instars. Unusual high temperature, which is not observed in nature, might affect the physiological condition of the larvae.