The influence of a DDGS diet on the development and oviposition rate of red flour beetle (Tribolium castaneum) (Herbst)

Dried Distillers Grains with Solubles (DDGS) is a byproduct when corn or other grains such as wheat, barley and milo are dry milled. The fractionized starch portion is fermented with selected yeast and enzymes in order to produce ethanol and carbon dioxide. The alcohol is then removed by distillation and the remaining residues are termed DDGS. The remaining solid (DDGS) contains protein, fiber, fat, oil and ash and can be used in livestock feeds or finishing diets to replace corn or other grains. As more of this product is available to the feed industry, the effect it might have on the vulnerability of animal feed to insect infestation is unknown. This research focused on the influence of DDGS as food and oviposition resource of red flour beetle (Tribolium castaneum (Herbst)) in contrast with a traditional flour and yeast (10%) diet. Larval development was significantly faster (P=0.0000) on flour/yeast (19.3±0.18 d) than on DDGS (45.06±0.69 d). DDGS and flour/yeast diet did not have a significant influence on egg hatch or pupation time. This indicates that DDGS is not as suitable developmental diet compared to a standard laboratory diet and that the addition of DDGS should not increase food vulnerability. Additionally, in a no-choice situation, the number of eggs laid was significantly lower (P=0.0000) on DDGS (17.37±1.22) compared to the flour/yeast (204.66±10.99) diet. In conclusion, DDGS is not a good substrate for red flour beetle and thus vulnerability of products with DDGS to red flour beetle should not increased.