桔小实蝇不同发育阶段过冷却点的测定

对桔小实蝇Bactrocera dorsalis (Hendel)不同发育阶段的过冷却点进行了测定。结果表明：同一虫期个体间的过冷却点出现不同程度的变异，但均服从正态分布。不同虫期的过冷却点差异显著，其中蛹的过冷却点最低（-12.2℃～-15.0℃）。老熟幼虫的过冷却点为-8.1℃。成虫的过冷却点最低值为7日龄雄虫（-10.5℃）和雌虫（-10.1℃），最高值为60日龄雄虫（-5.9℃）和雌虫（-6.4℃），但同一发育时期的雌、雄成虫之间的过冷却点没有差异。测定结果提示蛹期最有可能是该虫在温带地区越冬的虫态。

Supercooling capacity of the Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)

In this study, the variation of supercooling point (SCP) at different developmental stages of the Oriental fruit fly, Bactrocera dorsalis (Hendel) was examined. The results indicated that the SCP of B. Dorsalis varied significantly among individuals, but followed a normal distribution. The SCP at the pupal stage ranged from -12.2℃ to -15.0℃, which was the lowest among all the developmental stages. For the late 3rd instar larva, the SCP was -8.1℃. Values of SCPs varied significantly among adults of different age, the lowest SCPs were found in 7 day-old male adults (-10.5℃) and female adults (-10.1℃), and the highest SCPs were detected in 60 day-old male (-5.9℃) and female  (-6.4℃). However, there was no significant difference of SCP between male and female adults in the same age. The results suggest that B. dorsalis may overwinter in the pupal stage in temperate zone.