Predation by Red Flour Beetle 1 on Sawtoothed Grain Beetle 24

Abstract

When both the red flour beetle, Tribolium Castaneum (Herbst), and the sawtoothed grain beetle, Oryzaephilus surinamensis (L.), occurred in finely particulated diets that were more favorable to movement by the red flour beetle, the predation of T. castaneum on the sawtoothed grain beetle was accentuated. When the 2 species occurred in a mixture of rolled oats and standard flour beetle medium (1:1), the sawtoothed grain beetles remained in the rolled oats, and the red flour beetles generally segregated themselves in the standard medium, which reduced predation. Predation by the red flour beetles on sawtoothed grain beetles in cracked corn (substandard diet for the red flour beetle) was increased but in shelled whole peanuts, it was decreased. In both standard medium and cracked corn, both late-stage larvae and adults of the red flour beetle killed more eggs, early-stage larvae, and pupae of the sawtoothed grain beetle than late-stage larvae. This feeding resulted in an increase in the progeny produced by the red flour beetle.