Abstract: 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.

Key words: Bactrocera dorsalis, supercooling point, cold hardiness, overwintering