Interspecific Competition and Grain-Hosts Selection of Maize Weevil, <i>Sitophilus zeamais</i> (Motsch.) (Coleoptera; Dryophtoridae) and Larger Grain Borer, <i>Prostephanus truncatus</i> (Horn) (Coleoptera; Bostrichidae)

Abstract

Laboratory interspecific competition and grain-hosts selection experiments involving maize weevil (MW), Sitophilus zeamais (Motsch.) and larger grain borer (LGB), Prostephanus truncatus (Horn) were performed under ambient temperature and relative humidity (25˚C-35˚C and 70%-80% relative humidity) in their major host cereal, maize grains. The species reproductive rate and grain-hosts preference were evaluated by a number of emerged adults. In combined infestation, both species competed intensively by simultaneously increasing their individuals' emergence, 9-fold or greater than when reared alone. Even though both species simultaneously increased their progeny, S. zeamais was the dominant competitor and had a significant suppressant effect on P. truncatus. The selection result of grain-hosts showed that P. truncatus placed in the environment containing both uninfested maize grains and grains previously infested by S. zeamais, the insect prefers uninfested grains. Indeed, P. truncatus individuals' emergences were significantly more important to uninfested grains than to infested grains. The weevil-infested grains seemed to have deterrent and detrimental effects on P. truncatus. Conversely, S. zeamais selection of grain-hosts was significantly (P = 0.0001) more attracted by P. truncatus infested grains than to uninfested grains. Sitophilus zeamais individuals' emergences were significantly (P = 0.0008) more important to infested grains than to uninfested grains. The S. zeamais preference on grains previously infested would be stimulated by P. truncatus larval vibrations in grain. How to cite this paper: Ngom, D., Thiaw, C. and Sembène, M. (2020) Interspecific Competition and Grain-Hosts Selection of Maize Weevil, Sitophilus zeamais (Motsch.) (Coleoptera; Dryophtoridae) and Larger Grain Borer, Prostephanus truncatus (Horn) (Coleoptera; Bostrichidae). Advances in Entomology,