Metabarcoding and population genomics to assess usage of alternate habitats by Rhyzopertha dominica (Coleoptera: Bostrichidae)

Rhyzopertha dominica (Coleoptera: Bostrichidae) is a cosmopolitan stored product pest that causes significant economic losses to raw and finished commodities worldwide. Movement and prolonged storage of infested products are major drivers of infestations in food facilities; however, these insects also commonly reside in other agricultural landscapes, including tallgrass prairies, woodlands, and various types of croplands. Currently, it is unclear whether insects found in these landscapes represent resident populations, migratory individuals, or spillover from populations infesting nearby food facilities. Although previous studies have documented full development of R. dominica reared on seeds from native grasses and acorns and prior reports have documented feeding on woody and living plant materials, it is unclear whether they persist in alternate landscapes and or whether these populations could serve as sources for infestation of nearby food facilities. To fill these knowledge gaps, we collected R. dominica adults in pheromone-baited Lindgren traps at three different locations in Manhattan, KS across three field seasons (2017-2019) to assess population structure and admixture at the locations over time. The locations included a commercial grain elevator that buys and sells grain from over 24 counties in Kansas, a small flour mill that primarily processes grain harvested in nearby fields (Hal Ross Flour Mill, Kansas State University), and a native tallgrass prairie (Konza Prairie Biological Research Station). We also performed DNA metabarcoding analysis using plant rbcL amplicons from insect guts collected at Konza Prairie and a second native tallgrass prairie (Nine Mile Prairie, Lincoln, NE), to assess host plant usage.