[Flight capacity and facultative migration of cotton bollworm]

The flight capacity of moth cotton bollworm was studied by hanging flight installation. According to the flight rhythm and time, the individuals of population could be differentiated into long, medium, and short flight type. Laboratory stuies on the effect of temperature and food on pre-reproductive period, fecundity and life-span showed that the pre-reproductive period was only 2.13 +/- 0.67 days under 28 degrees C, and food or temperature had no significant effect on pre-reproductive period. The physiological period fitting for migration was quite short, only 1-2 nights. The population sources in Fengxian county, Jiangsu province and Chaoyang city, Liaoning province were studied by analysis of the dissecting of females ovary and the patterns of moth occurrence sequentially. The result indicated that the 2nd and 3rd generation moths in Chaoyang all or partly immigrated from other places, while in Fengxian, there was no migration. The flight capacity and reproductive characteristics of moth cotton bollworm were compared with other migratory or un-migratory species. The facultative migration and potential for migration of this species were discussed.