Herbivorous and carnivorous feeding byGeocoris punctipes(Say) on nectaried and nectariless cotton with and withoutHeliothis virescens(F.) eggs was measured using the radionuclides of carbon (14C) and phosphorus (32P). Leaf material ingested byC. punctipeswas measured as percentage of leaf sample disintegrations per min and was significantly greater for insects on nectaried cotton without eggs (12.08%) than on plants in the other treatments. Plant feeding was not significantly different on nectaried cotton with eggs (3.34%), nectariless cotton with eggs (1.97%), and nectariless cotton without eggs (0.35%).G. punctipesegg ingestion was not significantly different on the nectaried or nectariless cottons.