Abstract: To illustrate the effects of low-dose ⁶⁰Co-γ radiation on the development, phototactic behavior and sex pheromone titer in Helicoverpa armigera (Hübner), we examined the emergence rate, the deformity rate and longevity of H. armigera adults under five doses of radiation, and determined the rate of phototaxis and sex pheromone titer of H. armigera by phototactic behavior trial and pheromone extraction method. The results indicated that (1) there were no effects of ⁶⁰Co-γ radiation on adult emergence, deformity and longevity of the moth except for the irradiation of 20 Gy, under which the emergence rate was remarkably decreased by 16.67% (female) and 20.00% (male), and the deformity rate was increased by 10.00% (both female and male). (2) Both in photophase and scotophase, the rate of phototaxis and sex pheromone titer were increased. The biggest jump of the rate of phototaxis occurred in 3-day-old females in photophase (28.33%±3.33%-91.67%±4.41%), while that of sex pheromone titer occurred in 5-day-old females in scotophase (36.27±4.26 ng-59.13±4.63 ng), indicating that this dose irradiation (50 Gy) probably promoted the occurrence of phototactic behavior and the production of sex pheromone, while the radiation at five doses had no significant effects on phototaxis. (3) There was a declining trend following an increasing trend of the rate of phototaxis and sex pheromone titer as age increased. The biggest jump of the rate of phototaxis occurred in females in photophase and males in scotophase both after radiation (91.67%±4.41%-3.33%±1.67%), while that of sex pheromone titer occurred in females in scotophase after radiation (71.00±5.22 ng-3.63±1.47 ng). (4) There were no obvious differences in the emergence rate, the deformity rate, longevity and the rate of phototaxis between females and males in most treatments. This research may provide some theoretical basis for exploring the changes in phototaxis and physiological and biochemical characteristics of H. armigera, and also offer new ideas on taking advantage of physical and chemical communication for integrated management of H. armigera.

Key words: Helicoverpa armigera, radiation, emergence, longevity, phototactic behavior, sex pheromone