The Preliminary Study On Effects Of Mimic Milk Yetch And Rape Nectars On Oriental Armyworm Moth Mythimna Separata

Oriental armyworm Mythimna separata is one of migratory pests which caused heavy economic losses on crops in China. Milk vetch Astragalus sinicus and rape Brassica napus are primary nectar plants for oriental armyworm Mythimna separata. Milk vetch was reported as a key factor resulting severe outbreaks of oriental armyworm in china. we determined the type and content of free amino acids in milk vetch nectar and rape nectar、 the sugar content and nectar production per flower. to compare the effects of the two mimic nectars on oriental armyworm moth, to help to explore the mechanism of milk vetch adapt to armyworm moth, to clarify the doubt of study on armyworm moth population dynamic. We collected milk vetch and rape nectar by the capillary method, the type and content of free amino acids in milk vetch nectar and rape nectar were determined by the amino acid analyzer; milk vetch and rape nectar was collected with precise capillary pipettes to determine the sugar content and nectar production per flower. The armyworms adults were fed by the mimic nectars with the free amino acids and the sugar content of milk vetch and rape nectar, to compare feeding selectivity of armyworm moth to the two mimic nectars, to analyze the effects of the two mimic nectars on the fecundity、 preoviposition and adult lifetime of oriental annyworm moth. The main findings were summarized below:1. The date from Luoshan County showed that the sugar content of milk vetch nectar (30%～37%) was significantly lower than that of rape nectar (39%～46%) in bloomy flower. The nectar production per flower(NPPF)of milk vetch(<0.1μL)was relatively constant while NPPF of rape in the morning, noon and afternoon was1.3～1.6.μL,0.6～0.9μL and0.2～0.4μL respectively. In Zhengzhou city, the sugar content(ll%～68%)and NPPF(0.19-2.5μL) of rape were fluctuant greatly at different locates.2. The date from Luoshan County showed that there are17amino acids in both rape nectar and milk vetch nectar. The total free amino acid content in Rape nectar is2.47times as much as the total free amino acid content in milk vetch nectar; The content of free amino acid is different between the milk vetch nectar and rape nectar:the content of all of free amino acid in rape nectar is higher than the corresponding free amino acid in milk vetch nectar except Cys, Met、Phe, Lys, Ang; The content of Ala、Tys、Ser、Gly, Asp、 Pro in rape nectar is1436、1135、5.70、4.69、4.11、2.32as long as the corresponding amino acid in milk vetch nectar; The total free amino acid content in milk vetch honey is4.29times as much as the total free amino acid content in milk vetch nectar; There is different between the every component proportion of amino acid in nectar and honey; The Cys and Leu are in rape nectar but not in rape Honey. So we can not use milk vetch honey or rape honey instant of milk vetch nectar or rape nectar to study on the effects on armyworm moth, We scheme out mimic milk vetch rape nectars which core is amino acid.3. There was a significant difference on the preference of two mimic nectars to female moth A, There was no obvious difference on the preference of two mimic nectars to female moth B、C; After feeding the mimic nectars, There was a significant difference on the amount of propagation of female moth between the two mimic nectars. The mean egg-laying amount of armyworm female moth fed by the mimic milk vetch nectar was1237.00eggs and that fed by the mimic rape nectar was488.3eggs. There was no obvious effect difference on the preoviposition and adult lifetime of female moth fed by two mimic nectars. The mean preoviposition and lifetime of armyworm moth fed by the mimic milk vetch nectar were4.5and13d resp. and that fed by the mimic rape nectar were5.83d and15d respectively.