Characterization of mite communities phoretic on Ips pini (Say) in Wisconsin

The pine engraver, Ips pini, is an important pest of pine plantations, causing chronic loss in weakened trees. As with other bark beetles, multi-species interactions play important roles in its reproductive success. We are characterizing the composition and functional roles of phoretic mites associated with pine engravers in Wisconsin. Natural populations were sampled throughout the state by trapping live beetles both in flight and emerging from logs. Over 95% of pine engravers carried one or more phoretic mites (median 7 mites per beetle, n=576). We have identified eight commonly associated species (22 total): Dendrolaelaps quadrisetus, Elattoma spp., Ereynetes propescutulis, Histiostoma varia, Iponemus confusus, Schaarschmidtia ips, and Trichouropoda australis. H. varia, I. confusus, and D. quadrisetus were the most abundant, each occurring on ~50% of beetles.