Development of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) on rice milling components and by-products: Effects of diet and temperature

Authors: ARTHUR, FRANKLIN; HALE, BROOK - ARKANSAS STATE UNIVERSITY; STARKUS, LAURA - ARKANSAS STATE UNIVERSITY; Gerken, Alison; Campbell, James - Jim; MCKAY, TANJA - ARKANSAS AGRICULTURAL EXPERIMENT STATION

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/7/2018
Publication Date: 1/15/2019
Citation: Arthur, F.H., Hale, B.A., Starkus, L.A., Gerken, A.R., Campbell, J.F., McKay, T. 2019. Development of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) on rice milling components and by-products: Effects of diet and temperature. Journal of Stored Products Research. 80:85-92. https://doi.org/10.1016/j.jspr.2018.11.001.
DOI: https://doi.org/10.1016/j.jspr.2018.11.001

Interpretive Summary: The red flour beetle is an important pest of wheat flour mills, and recent studies show that this insect is prevalent in rice mills as well. There is a considerable body of research on how this insect can survive on whole and cracked wheat, but little information as to how well the red flour beetle can survive on rice components and by-products produced as part of the milling process. A detailed study was conducted by exposing either eggs or 1-2-day old larvae on selected rice components and by-products (diets). The diets best suited for development were brown rice, rice flour, rice bran, milled whole kernels, and milled broken kernels. Developmental time from the larval to the adult stage on these suitable diets decreased as temperatures increased, with differences in developmental times between the diets depending on temperature. Models were constructed that showed how population increase dramatically increases with temperature, regardless of diet. Results of this study demonstrate the ability of the red flour beetle to develop and persist on different products that are produced when rice is milled. Managers can use this information to improve sanitation and cleaning practices to minimize insect food sources in rice mills, which may also improve efficacy of insecticides used in control programs.

Technical Abstract: Development of Tribolium castaneum (Herbst), the red flour beetle, was assessed on nine different components or rice by-products (i.e., diets) commonly found in rice mills, in two separate experiments. In the first experiment, eggs did not develop to the adult stage on rough rice hulls, paddy rice dust, and milled rice dust, while eggs developed to the adult stage to some extent on rice flour, milled whole kernels, brown rice, milled broken kernels, and bran. The lowest percentage of development was on brown rice, and adults that emerged on brown rice had smaller elytra compared to adults emerging on the other diets. In the second experiment, 1-2-day old neonates were exposed on the diets listed above and held at 22, 27, 32, and 37°C. At all temperatures, development to the pupal and adult stages was slowest on rice flour. At 22°C, development to those stages took about twice as long compared to development at 27°C. As temperature increased developmental times were reduced. Even though neonates developed slowest on brown rice overall adult emergence was not affected. Predictive models were estimated for potential population development on the diets. At 22 and 27°C adult size as measured by elytra length was greatest when they developed on bran, while body weight was generally lowest for adults that developed on brown rice. Results show that T. castaneum can utilize rice components and by-products produced during the rice milling process, although not all components or by-products were optimal for development, and emphasis should be placed on cleaning and sanitation to remove food sources to limit infestations. Mill managers can use these results to show the importance of sanitation, and potentially improve overall pest management programs inside the mill.