Induction Law Of Aphis Glycines Matsumura Gynoparae And Males At Different Temperatures And Photoperiods

Soybean aphid,Aphis glycines,is an important pest of soybean,Glycine max.Life cycle of A.glycines is characterized as heteroecious and holocyclic.Gynoparae and males are sexual morphs of A.glycines,which are important to maintain its population growth,increase genetic communication and adapt the environment in their life cycle.In this study,gynoparae and males of A.glycines were induced by temperatures and photoperiods in their successive three and two generations,respectively.In addition,an experiment to study the formation dynamics of A.glycines wingless oviviparae,gynoparae and males at different temperatures and photopeiods was also conducted.When A.glycines produced wingless oviviparae,males and gynoparae,some substance content and hormone level of A.glycines adults were determined and analyzed.The conclusions were as follows:In induction experiment on gynoparae and males of A.glycines in their successive three generations,the temperatures was set 20℃,23℃ and 26℃ with a short photoperiod of 10 L:14 D.It showed that gynoparae and males of A.glycines could be successfully induced in G2 cohort,with G0,G1 and G2 being reared at 20℃ and 23℃with a photoperiod of 10 L:14 D.Gynoparae and males of A.glycines could also be successfully induced in G2,with G0 and G1 at 20℃ and 23℃ with a photoperiod of 10 L:14 D,G2 being transferred at a long photoperiod.Gynoparae of A.glycines could not be induced with G0,G1 and G2 being reared at 26℃ with a photoperiod of 10 L:14 D.Males of A.glycines could be induced when adults in G1 cohort were reared at a short photoperiod of 10 L:14 D.In induction experiment on gynoparae and males of A.glycines in their successive two generations,the temperatures was set 14℃,17℃,20℃,23℃ and 26℃ with a short photoperiod of 10 L:14 D.Gynoparae and males of A.glycines could be successfully induced in their G2 cohort with 14-23℃ and a photoperiod of 10 L:14 D.Only males and virginoparae could be induced in the G2 cohort at 26℃ and a photoperiod of 10 L:14 D.Gynoparae of A.glycines occur earlier than males or as same early as males when induction experiment were started from each stadium of A.glycines at 14-20℃ with a photoperiod of 10 L:14 D.When adult of A.glycines were reared at 14-20℃ with 10 L:14 D photoperiod,gynoparae and males could be induced in the G2 cohort.When adult of A.glycines were reared at 23-26℃ with 10 L:14 D photoperiod,only males could be induced in the G2 cohort.Gynoparae and males of A.glycines occurred simultaneously at 17-23℃ and a photoperiod of 12L:12 D;gynoparae disappeared earlier than males and there were still larger numbers of males when gynoparae disapperaed.No gynoparae and males were induced when A.glycines were reared at 29℃and a phototperiod of 12 L:12 D.At 20℃ and a photoperiod of 8L:16D or 10 L:14 D,gynoparae occured earlier than males or as same early as males,but they disappeared earlier than males..There were both no significant differences in protein content(with data of 17.63±0.68 and 19.32±2.27 μg/g)and reducing sugar content(with data of 14.29±0.59 and 13.48±0.97 μg/g)in body of A.glycines adults when they produced males and virginoparae,which were all lower than adults reproduced gynoparae(with data of 70.05±3.56μg/g and 63.24±15.99 μg/g).There were no significant differences in melatonin content of A.glycines adults when they produced the gynoparae,males and virginoparae,respectively.When A.glycines produced gynoparae and males,content of juvenile hormone in adult body were92.54±8.82 and 85.53±6.64 ng/g,which were both higher than that of A.glycines adults reproduced virginoparae,with data of 48.30±2.15 ng/g.