Development of Tribolium castaneum (Herbst)(Coleoptera: Tenebrionidae) on sorghum milling fractions

Authors: Arthur, Franklin; Bean, Scott; Smolensky, Dmitriy; Gerken, Alison; SILIVERU, KALIRAMESH - Kansas State University; Scully, Erin; Baker, Neil

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2020
Publication Date: 4/22/2020
Citation: Arthur, F.H., Bean, S.R., Smolensky, D., Gerken, A.R., Siliveru, K., Scully, E.D., Baker, N.J. 2020. Development of Tribolium castaneum (Herbst)(Coleoptera: Tenebrionidae) on sorghum milling fractions. Journal of Stored Products Research. 87:101606. https://doi.org/10.1016/j.jspr.2020.101606.
DOI: https://doi.org/10.1016/j.jspr.2020.101606

Interpretive Summary: Sorghum is receiving increased attention in the United States for use in biofuels and as a value-added food product. However, there has been little research regarding susceptibility of raw grain sorghum or milled sorghum fractions to stored product insects. We conducted a series of studies to determine if the red flour beetle, a major pest of wheat and rice mills, could survive and develop on different milled sorghum fractions: Bran, Coarse and Fine Grits, Flour, Red Dogs, and Shorts. In the first test, adult red flour beetles successfully laid eggs on these fractions and larvae developed to the late larval, pupal, and adult stages. In the second test, one-to two-day old larvae (neonates) were placed individually in vials containing one gram of one of the six fractions, and held at 80°F. Development to the adult stage was at least 80%, depending on the fraction. In the final test, neonates were placed in vials containing one gram of one of the six fractions, and held at 70, 80, 90, or 100°F. Development to the adult stage took between 3-5 weeks at 100, 90, or 80°F, but between 3-4 months at 70°F. Percentage development to the adult stage at this temperature was lower on some of the fractions compared to the warmer temperatures. Results show that red flour beetle could colonize these sorghum fractions if they were present inside sorghum milling operations, thus contributing to resident infestations that could develop inside the mill. Cleaning and sanitation, and not allowing these materials to accumulate around milling equipment should be emphasized, especially during the warmer months of the year.

Technical Abstract: A series of tests was conducted to determine if Tribolium castaneum Herbst, the red flour beetle, could survive on six milled sorghum fractions: Bran, Coarse Grits, Fine Grits, Flour, Red Dogs, and Shorts. In the first test, parental adults were exposed on the fractions, removed, and then the fractions were held for six-seven weeks at 27° C. Late instar larvae and progeny adults were present in all fractions. In the second test, at least 80% of single neonates (1-2-day-old larvae) held on one gram of a fraction were able to complete development to the adult stage. In the final test, individual neonates were held one gram of a fraction at 37°C, 32°C, 27°C, or 22°C. Time to adult emergence at each temperature ranged from 17-23 days, 21-27 days, 28-50 days, and 67-113 days, respectively, depending on the specific fraction. Logistic functions were compared for mean developmental times for each temperature-fraction combination. The six fractions were also analyzed for ash, fat, fiber, moisture, protein, and starch content. The fractions varied with respect to these chemical constituents; fat and moisture content were negatively correlated with development in some comparisons, though overall there was no correlation between these chemical components and neonate development on the fractions. Temperature had an obvious effect on neonate development, which has implications for assessing risk of pest infestations inside sorghum mills during warmer months of the calendar year. In addition, T. castaneum will reproduce and develop on the measured sorghum fractions, which are commonly produced during the sorghum milling process. Sanitation and removal of residual materials such as the measured fractions could also help with overall pest management of T. castaneum.