Saproxyly in predatory mites? Mesostigmata in decaying log habitats versus litter in a wet eucalypt forest, Tasmania, Australia

Abstract

In a wet eucalypt forest in Tasmania, Australia, I tested the hypothesis that decaying wood habitats are important for predators and occasional scavengers of Mesostigmata by harbouring species that are largely absent from forest floor litter. Results show that the assemblage of mesostigmatic mites inhabiting rotting logs (Eucalyptus obliqua) and epixylic mosses (46 species) is distinct from the forest floor litter assemblage (47 species), with 45.7% of species (21/46 species) restricted to log habitats. Eight species (7 from Ologamasidae, 1 from Ascidae) were significantly associated with log habitats. With the exception of the Ascidae (Xenoseius sp.) which may be phoretic, none of these species belongs to genera known to use phoresy on insects for dispersal. These results indicate that dead wood help sustain the local biodiversity of Mesostigmata and suggest that some free-living predatory mites may be saproxylic.