Interaction between Certain Natural Enemies and some Stored-Grain Insect Pests

Abstract

The relationship between certain natural enemies (the pteromalid parasitoid, Anisopteromalus calandrae Howard (Hymenoptera: Pteromalidae); the predatory ant, Monomrium sp. and the predacious mite, Blattisocius sp.) and some stored-grain insects was investigated under laboratory conditions. The parasitoid, A. calandrae exhibited a positive response to larval feces extracts of the cowpea beetle. Callosobruchus maculatus (F) and grain weevil, Sitophilus granarius (L)in acetone and ethanol solvents. Odors emitted by adult extracts of C. maculatus (in ether and acetone) or by Bruchidius incarnatus (in ethanol and acetone) significantly attracted the workers of the predatory ant, Monomrium sp. The searching rate and mutual interference values of the parasitoid, A. calandrae, and the predatory mite, Blattisocius sp. were estimated in response to different hosts. A. calandrae females showed a relatively higher searching rate and mutual interference value in response to C. maculatus reared on cowpea than those reared on chickpea grains. The predatory mite, Blattisocius sp. exhibited the highest searching rate with low mutual interference values on C. maculatus eggs in comparison with B. incarnatus eggs.