Effects of irradiated eggs on development and reproduction of Bactrocera dorsalis(Hendel)

To determine effects of egg irradiation on development and reproduction of Bactrocera dorsalis (Hendel), three different ages of B. dorsalis eggs (12-, 24-and 36-h-old) were irradiated at 5.0, 10.0, 15.0, 20.0, 25.0, 30.0, 35.0 and 40.0 Gy separately by ⁶⁰Co. The egg hatch rates were observed and compared with control. The results showed that dose of 5.0 Gy and above significantly inhibited 12-h-old egg hatching. There were no significant differences among doses in hatch rate of both 24-and 36-h-old eggs' hatch rates. Irradiated 36-h-old eggs were chosen to do fellow-up studies for their higher egg hatch rates. The results showed that no gender differences existed for all doses' effects. Doses of 20 Gy and above significantly reduced pupal weight and inhibited adults emerging. As radiation dose increased, adult fly abilities and mortalities increased but hatch rates of progeny eggs decreased. In conclusion, irradiation doses of 15-20 Gy on 36-h-old could inhibit adult emerging but showed little effects on development and quality of larvae and pupae. This research would provide a scientific basis for mass rearing egg-pupal parasitoids of B.dorsalis with nuclear irradiation. (authors)