Ants (Formicidae) have long been an insect group of great interest to the scientific world, whether for their ecological roles, feeding strategies, or social behaviors. They form complex colonies, harboring resources that can potentially be exploited by myrmecophiles (organisms living in association with ants). Myrmecophily has been studied in detail for Coleoptera, but mites (Acari), the most frequent of ant guests, remain largely unstudied. Previous work has focused primarily on descriptions and has provided little ecological information.
The first study is an effort to provide a more robust list of the often overlooked inhabitants of ant nests focusing on Ohio, a state that has yet to be mentioned in any myrmecophilous mite studies. A general survey of common Ohio ants was conducted from April 2008-March 2010. Phoretic mites were individually removed from ants and debris in 273 colonies. Mite collections totaled 198 species: 151 species phoretic and at least 47 mite species in non-phoretic relationships within the ant nests. Phoretic mites consisted of representatives of the cohort Astigmata (Histiostomatidae and Acaridae), the cohort Heterostigmatina (Scutacaridae, Pygmephoridae, and Microdispidae), and the suborder Mesostigmata (Laelapidae, Antennophoridae, and Uropodina). Many mite species were host specific and attachment site specific. An unusually large number of mite species was found to be associated with the ant genus Lasius, possibly the result of social parasitism. Post hoc statistical analyses show significantly greater mite diversity in colonies when 1) in the ant subfamily Formicinae, 2) the colony is in the woods, 3) the nest substrate is wood, 4) the colony is populous, 5) the ants are large, and 6) the ant species establishes its nest parasitically.
A second study focused on the seed harvester ant Messor pergandei and its acarine associates. At least seven mite species are phoretically associated with M. pergandei: Armacarus sp., Lemanniella sp., Petalomium sp., Forcellinia sp., Histiostoma sp., Unguidispus sp., and Cosmoglyphus sp. Most of these species show preference for specific phoretic attachment sites and most preferentially board female alates rather than male alates. Five mite species were found in low numbers inhabiting the chaff piles: Tydeidae sp., Procaeculus sp., Anystidae sp., Bakerdania sp., and Tetranychidae sp. The phoretic Petalomium sp. was observed consuming fungus on a dead dealate, but the roles of the other species are still unclear.