A limiting factor in the abundance of predatory phoretic mites (Acari: Macrochelidae): the seasonal abundance of their phorionts (dung beetles) in southern France

The effects of host (dung beetles; Coleoptera: Scarabaeoidea) activity on seasonal abundance of phoretic mites (predatory macrochelids) were investigated in experimental dung pads under Mediterranean climatic conditions. Macrocheles robustulus and Macrocheles merdarius were collected only in spring and autumn. The most abundant macrochelids (Macrocheles glaber group; >90%) were rare in the hottest days and during winter. Mite abundance and dung beetle activity were correlated. The distribution (aggregate or not) of macrochelids in both pads and beetle traps was interpreted as a consequence of the availability of carriers that were found greatly affected by unfavourable meteorological conditions (temperature and rainfall). By their abundance and because they are opportunistic in the choice of host, the M. glaber group species can be considered the most efficient in coprophilous fly control. [PUBLICATION ABSTRACT]