Distance-based Decision-making in Oviposition by Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) on Low- and No-gluten Flours.

The increasing popularity of low- and no-gluten flours as wheat flour alternatives has driven the need to understand risks of insect pest infestation in these products. Previous research using no-choice bioassays found that the red flour beetle, Tribolium castaneum Herbst can oviposit and develop on a range of alternative flours; here we test T. castaneum preference by assessing attraction in a wind tunnel assay and oviposition preference in both small- and large-scale choice assays between alternative and wheat flour. Some flours such as buckwheat, teff, millet, rice, and rye elicit similar responses as wheat flour for both attraction and oviposition. Other flours such as cassava and oat were not preferred for either oviposition or attraction behaviors. Flours like sorghum and amaranth, had mixed preferences for oviposition, with decreased oviposition in the small arena but not the large arena. Comparisons to published developmental success rates of T. castnaeum on these dietsindicate that females can choose diets on which they have high developmental success, such as buckwheat or teff, and avoid flours like cassava where developmental success is low. However, mismatch of oviposition preference and developmental success also occurs, in flours such as rice and amaranth. These results suggest the red flour beetle has limited ability to make adaptive food selections for egg laying. Further analysis of the chemical and physical properties associated with preferred and nonpreferred flours can provide information on cues associated with egg laying as well as how these cues could be exploited in pest management programs.