Phoretic mite assemblage of the pinyon pine beetle, Ips confusus (Curculionidae: Scolytinae), in Arizona

Mites are among the most common associates of bark beetles and they can influence the ecology and microbial composition within bark beetle-colonized trees. The pinyon pine engraver, Ips confusus is a common beetle in pinyon trees in the southwestern United States, but the mite composition associated with this beetle has been little studied. In this study, we quantify the abundance, diversity, and attachment locations of phoretic mites on Ips confusus that emerge from naturally infested trees. In total, we observed 342 beetles for mites, 95% of which had at least one mite. We collected a total of 5842 mites, representing seven families and seven species: Cercoleipus coelonotus (Cercomegistidae) Dendrolaelaps quadrisetosimilis (Digamasellidae), Ereynetes propescutulis (Ereynetidae), Iponemus confusus confusus (Tarsonemidae), Mexecheles cf. virginiensis (Cheyletidae), Proctolaelaps subcorticalis (Melicharidae), and Trichouropoda californica (Trematuridae). We calculated the average number of mites per beetle to be 18, with a maximum of 147 mites on a single beetle. The vast majority of mites (98% of total abundance) was represented by three species (I. c. confusus, D. quadrisetosimilis, and T. californica). Attachment locations on the beetle varied across mite species, with mite species exhibiting a preference for specific locations. Mite abundances on emerging host beetles varied over time, with some species occurring mostly on early-emerging beetles, while others occurred on later emerging beetles.