2nd Place: The phoretic mite (Arachnida: Acari) assemblage of the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Curculionidae)

While there have been previous studies on the phoretic mite assemblages of various Dendroctonus spp. bark beetles (Coleoptera: Curculionidae), the mite assemblage of the Douglas-fir beetle, Dendroctonus pseudotsugae, has not received much attention. We investigated the prevalence, abundance, and phenology of mite operational taxonomic units (OTUs) associated with Douglas-fir beetles. We collected Douglas-fir beetles in pheromone baited traps at two sites in and near Prince George, British Columbia, Canada during the summer of 2021, and in 15 traps in Prince George throughout the summer of 2022. We collected mites from all surfaces of the beetles’ body and sorted them as morphospecies. We successfully DNA barcoded 116 mites and those results returned eight OTUs that corresponded almost identically with our morphospecies analysis. The eight OTUs mainly reside within five families: Pygmephoridae, Tarsonemidae, Rhodacaridae, Melicharidae, and Urodinychidae. 100% of beetles hosted mites, and the mean number of mites per beetle was 76.15 ± 6.16 with a few beetles hosting several hundred mites. The prevalence and abundance varied considerably between mite OTUs. With the beetles and mites collected during the summer of 2022, we plan to investigate how beetle emergence phenology may impact mite abundance throughout the insect’s flight period, as well as investigate any differences in mite prevalence and abundance compared to those in 2021.