Bt crops, such as maize and cotton, are subjected to environmental risk assessments for non-target enemies, including natural enemies that suppress the populations of the pests. Cornell University scientists H.H. Su and colleagues used Bt resistant fall armyworm (Spodoptera frugiperda) and cabbage looper (Trichoplusia ni) as prey for assassin bug (Zelus renardii), a common predator in maize and cotton fields. Several fitness parameters of assassin bug were assessed when it fed on resistant fall armyworm that fed on Bt maize or resistant cabbage looper that fed on Bt cotton.