온도와 광주기에 따른 목화진딧물의 유성형 발생 예측모형

Abstract

This study was conducted to examine the environmental factors that induce the switch from parthenogenetic reproduction to sexual reproduction and to construct a forecasting model for the occurrence time of sexual morphs in holocyclic cotton aphid Aphis gossypii(Hemiptera: Aphididae). The effects of photoperiod and temperature were unequivocally demonstrated to have a direct influence on the production of sexual morphs in holocyclic A. gossypii . Above 21℃, all the photoperiod treatements could not induce the production of sexuals. Under the photoperiod of 12.0～12.5h, lower temperature induced higher production ratio of gynopara and male. Also, under 15～18℃, shorter photoperiod induced higher production ratio of gynopara and male. In the treatement of 13 h of photoperiod, any sexuals were not induced regardless of temperature. It was demonstrated that the critical day length required to induce sexual morph production varies depending on temperature. In this study, a 3℃ rise in temperature decreased by about 21 minutes in the critical day length. The production of male was occurred after the middle of the reproductive sequence of subsexupara. Two forecasting models (Advance model and 50% model) for the occurrence time of sexual morphs were developed using the results of experiment in relation to photoperiod and temperature. The forecasting models were simulated to predict the occurrence time of sexual morphs, and then, for validation of the models, model outputs were compared to the actual male occurrence serveyed in 5 sites from Oct. 2014 to Dec. 2014. As a result of validation, the model of advance mode showed statistically better performance than that of 50% mode. Until more improved model is developed, the present model should be useful for understanding the population dynamic of holocyclic A. gossypii in late season.