Biology, demography and community interactions of Tarsonemus (Acarina: tarsonemidae) mites phoretic on Dendroctonus frontalis (Coleoptera: Scolytidae)
- Dendroctonus frontalis, the southern pine beetle, is associated with a diverse community of fungi and mites that are phoretic on the adult beetles. Tarsonemus ips, T. kranzti and T. fusarii (Acarina: Tarsonemidae) may interact within this community in ways that link the population dynamics of D. frontalis, the mites and three dominant species of fungi. We explored species associations by comparing the dietary suitability of different fungi for Tarsonemusspp.
- All three mite species fedand reproduced at high rates when feeding on the bluestain fungus, Ophiostoma minus, which is an antagonist of D. frontalis larvae.
- Mites also had positive population growth rates when feeding upon Ceratocystiopsis ranaculosus, one of the mycangial fungi, but could barely reproduce when feeding upon Entomocorticium sp. A., the mycangial fungus that is most suitable for D. frontalis.
- During the time from colonization of a tree by D. frontalis adults until departure from the tree of their progeny (~ 40 d at 30oC), mite populations feeding upon O. minus can increase by factors of up to 209 (T. fusarii), 173 (T. ips or 384 (T. krantzi). These high growth rates are allowed by rapid development (age of first reproduction = 8-9d), high fecundity (~ 1egg/d) and high longevity (>28 d).
- Precocious mating increases the chance that females are mated prior to colonizing a new tree and arrhenotokous parthengensis permits reproduction by unmated females.
- Tarsonemus mites may introduce negative feedback into D. frontalis population dynamics by generating indirect interactions between D. frontalis and O. minus.