Does Prior Feeding Behavior by Previous Generations of the Maize Weevil (Coleoptera: Curculionidae) Determine Future Descendants Feeding Preference and Ovipositional Suitability?

The maize weevil Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) is an important pest of stored grains, predominantly corn (Zea mays), wheat (Triticum spp.), rice (Oryza spp.), and sorghum (Sorghum bicolor) (all Poaceae). In Africa, post-harvest grain losses of maize amounts to about US $4 billion annually, with an estimate of 10 to 88% loss of maize due to stored grain pests (FAO 2010; Ojo & Omoloye 2012). Current control methods are the application of an insecticide, cultural practices, and the development of resistant grain. Unfortunately, there is no effective trapping system for control of the maize weevil. Previous studies have indicated that the odors associated with the grains upon which the weevils feed, mate, and oviposit are known to be attractive. To better understand this behavior, a study was developed to investigate the weevil's attraction to dry grains with and without the presence of the commercial pheromone lure. The weevil's ability to develop on specific grains also was investigated. The weevils were reared on 4 types of grain to determine, if presented a choice, whether they would prefer the grain upon which their parents and they themselves fed as larvae. This research demonstrates that previous feeding did not influence the weevil's attraction to a certain grain. The isolation of key corn semiochemicals should be the focus in the development of an attractant for S. zeamais. These findings eliminate the need to develop individualized attractants that would have to be tailored to weevils feeding upon specific hosts.