The competition model of species at different types of habitat and simulation studies and applications FIELD DISPERSAL ABILITY OF IRRADIATED COTTON BOLLWORM HELICOVERPA ARMIGERA (HUBNER) FIELD DISPERSAL ABILITY AND TAXIS TO SEX PHEROMONE OF IRRADIATED F 1 MALE ASIAN CORN BORER Effects of Seed Mass on Germination of Lamiaceae Species in the Eastern Qinghai-Tibetan Plateau