| Oriental armyworm Mythimna separata is one of migratory pests which caused heavy economic losses on crops in China. During the 1950-1970, significant correlation was existed between armyworm outbreak and nectar source plants. This paper was aimed at the relationship between nectar plant and Oriental Armyworm Moth (OAM), exploring the selection mechanism of OAM on nectar plants volatiles, as well as the nutritional effect of different plants' nectar for OAM. The behavioral responses of OAMs to flowering rape, milk vetch were observed in the field. Simultaneously, the feeding behavior of OAMs to honey solution was observed. In the laboratory, the behavioral responses of OAMs to volatile extracts of milk vetch and rape were compared. Nectar nutritional effects of rape and milk vetch to moths were compared by following methods: (1)Nutrient solution simulating honey formula of milk vetch, rape feeding moths respectively, (2) Sugar solution added flowers of vetch, rape feeding moths respectively. The main findings were summarized below:1. The behavioral responses of OAMs at day 1 to the plants was weak; the behavioral responses of OAMs at first half preoviposition stage except day 1 were more stronger, but the responses of OAMs at second half preoviposition stage became very weak. During oviposition period, the male and female OAMs displayed certain tropism to the flowering rape and the milk vetch, the female OAMs performanced intense behavior of oviposition. From eclosion to oviposition, the OAMs showed similar directional behavior response frequency to the flowering rape and milk vetch. Female and male OAMs both all displayed a great deal of food intake during several days after eclosion, remarkable reduction in food intake in middle-aged moths, increasing food intake after mating.2. The preference of OAM to the odors of milk vetch and rape was examined by Y-tube olfactometer. The attractant rate of milk vetch flowers volatile extract to OAM was 28.35% , while that of the rape flowers volatile extract was 8.35 %.3. The effects of two kinds of nutrient solution simulating honey formula of milk vetch and rape on OAMs were compared. There was a significant difference on female moth fecundity (P <0.05): OAM fed by nutrient solution simulating honey formula of milk vetch laid 301.4 eggs per female, the preoviposition was 4.8 days, with an average life of 13 days, while that OAMs fed by Nutrient solution simulating honey formula of rape were 569.4,4.6 days ,12 days respectively.4. The effects of two kinds of sugar solution added flowers of vetch and rape on OAMs were compared. There was a significant difference on female moth fecundity (P <0.05): OAMs fed by sugar solution added flowers of vetch laid 646.22 eggs, the preoviposition was 4.5 days, with an average life of 12 days, while that OAMs fed by sugar solution added flowers of rape were 895.9,4.8 days, 12.9 days respectively.
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