Effect of Age and Feeding on Heat Tolerance in Each Larval Instar Period of Bactrocera dorsalis and Bactrocera cucurbitae (Diptera: Tephritidae)

摘要

First instar larvae (early-, middle- and late-age), second instar larvae (early- and late-age), and third instar larvae (early-, middle- and late-age) of Bactrocera dorsalis and B. cucurbitae were immersed in hot water at 45.0t in order to investigatethe effect of age within each larval instar period on heat tolerance. The effect of feeding was also examined for first instar larvae. The results of hot water immersion showed that heat tolerance decreased in late-age in the case of first instar and second instar larvae of the two species. In the case of third instar larvae, heat tolerance of B. dorsalis increased but not for B. cucurbitae. Nonfeeding first instar larvae tended to be more tolerant to heat than feeding larvae of B. dorsalis and B. cucurbitae. These results suggest that the effect of age on heat tolerance within each larval instar period should be considered in disinfestation tests to establish a quarantine heat treatment schedule to kill fruit flies in fruits completely.