Phoretic mites have the potential to disrupt the interactions between bark beetles and their mutualistic fungi by transporting and introducing antagonistic fungi into beetle galleries and the surrounding phloem. Several species of Tarsonemus mites, phoretic on the southern pine beetle, carry and feed on the bluestain fungus, Ophiostoma minus, an antagonist of southern pine beetle. We hypothesized that the population dynamics of southern pine beetles are influenced by negative feedback through community interactions involving beetle mutualists, mite mutualists, and mites. We found that O. minus abundance within bark is positively correlated with mite abundance but negatively correlated with southern pine beetle survival. The abundance of O. minus gradually increased as southern pine beetle infestations progressed through time, hypothetically affecting the eventual decline of beetle populations. Changes in O. minus abundance were more tightly correlated with mite abundance than with the prevalence of O. minus on attacking beetles. Experimental manipulations of mite abundances resulted in increased O. minus in the bark. Mite dynamics and behavior, and O. minus ecology in bark, likely play an important role in the population dynamics of southern pine beetle.
Species 1: Coleoptera Scolytidae Dendroctonus frontalis (southern pine beetle)
Species 2: Acari Tarsonemidae Tarsonemus krantzi
Keywords: mutualism, phoretic
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