Oviposition and development of Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) on different types of flour

Authors: Gerken, Alison; Campbell, James - Jim

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/14/2020
Publication Date: 10/17/2020
Publication URL: https://handle.nal.usda.gov/10113/7151840
Citation: Gerken, A.R., Campbell, J.F. 2020. Oviposition and development of Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) on different types of flour. Agronomy. 10(10):1593. https://doi.org/10.3390/agronomy10101593.
DOI: https://doi.org/10.3390/agronomy10101593

Interpretive Summary: Insects infest wheat and wheat-based products such as flour, costing the food industry millions of dollars in lost revenues due to contaminated food and management costs. Alternatives to traditional wheat flour that are gluten free or lower in gluten have increased in popularity and the market for these products is valued at over $21 billion USD. However, little is known about the ability of insects to infest and survive on these alternatives to wheat flour. Here we used a common stored-product insect pest, the red flour beetle, to test the risk of infestation of a group of commercially available alternative flours. We found that females laid high numbers of eggs on barley, buckwheat, millet, teff, spelt, rice, and rye flour and offspring had a high probability of developing to adults. Other flours like almond, amaranth, cassava, coconut, and potato had low numbers of eggs laid in them and offspring were not able to survive on these flours. Corn, garbanzo, oat, and quinoa flour had eggs laid in them but had few offspring survive. The time it took eggs to become adults also varied among the flours, with buckwheat, barley, spelt, and teff taking a similar amount of time to emerge as adults as wheat flour. Red flour beetle developed more slowly on quinoa, oat, rice, rye, and sorghum flours. Our study indicates that alternative flours vary in the level of risk of infestation by red flour beetle and this information can be used in the management of insect pests in food facilities that are seeing increasing diversity in flour types.

Technical Abstract: Commercial availability of low-gluten or gluten-free flours has been increasing due to consumer demands, which raises new challenges for the management of stored product insects since little is known about the susceptibility of these flours to infestation. Here we measured oviposition and development of Tribolium castaneum, the red flour beetle, a major pest of wheat and rice mills, on 18 different commercially available flours (almond, amaranth, barley, buckwheat, cassava, coconut, corn, garbanzo, millet, oat, potato, quinoa, rice, rye, sorghum, spelt, teff, and wheat) to assess the level of risk. The average number of eggs laid was highest for teff flour, with wheat, rice, buckwheat, sorghum, barley, rye, and spelt flour also having high oviposition. The lowest oviposition was for potato, quinoa, amaranth and cassava. Holding the eggs laid in these flours and evaluating ability to develop to the adult stage demonstrated that the average number of adult progeny was highest for teff and wheat, followed by buckwheat, rye, oat, spelt, and millet. In an experiment where single eggs were placed directly in flour, the highest percentage development was in barley, buckwheat, sorghum, spelt, teff, and wheat. Time for 50% of single eggs to develop to adults was quickest for sorghum, spelt, teff, and wheat, while sorghum, buckwheat, corn, spelt, and barley had the quickest development of 90% of eggs to reach adults. There was substantial variation among the different flours which indicates variation in risk of insect infestation. As consumer interest in these flours continues to grow and these alternative flours become more prevalent in food facilities, understanding what diets insects successfully infest is critical to developing management tools.