Feeding activity of Sitophilus zeamais (Coleoptera: Curculionidae) on resistant and susceptible corn genotypes

The maize weevil, S. zeamais Motschulsky, exhibited two types of feeding behavior on corn seeds. Adults sometimes penetrated the pericarp over an irregularly sized area and fed lightly on the surface of the endosperm (shallow feeding). On other occasions they chewed through the pericarp in a localized area and fed to a much greater extent on the endosperm (deep feeding). Both sexes fed in these ways. Initially there was more shallow feeding followed by an increase in deep feeding in a susceptible line, Pa762. Deep feeding was the predominant activity throughout the test on Va26, a resistant line. The amount of deep feeding was more highly correlated with oviposition than was shallow feeding.