To clarify how transgenic cotton contributes to these outbreaks, a four-year field investigation of population dynamics and laboratory life table studies were carried out from 2007 to 2010 to evaluate the impact of two transgenic cotton cultivars (SGK321 expressing Cry1Ac þ CpTI and GK12 expressing Cry1Ac) and their corresponding parental non-transgenic lines (Shiyuan321 andSimian3) on A. lucorum