Clive S. A. Stinson’s scientific contributions

Mites of the genus Thyreophagus (Acari: Acaridae) are distributed worldwide; they inhabit concealed habitats and include several beneficial and economically important species. However, species identification is difficult because many species are poorly described or delimited and their phoretic stages are unknown or uncorrelated. Furthermore, Thyreophagus is interesting because it includes entirely asexual (parthenogenetic) species. However, among the 34 described species of Thyreophagus, the asexual status is confirmed through laboratory rearing for only two species. Here, we provide detailed descriptions of five new species from North America (four) and Europe (one) based on adults and phoretic heteromorphic deutonymphs. Four of these species were asexual, while one was sexual. For most of these mites, the asexual status was confirmed and phoretic deutonymphs were obtained through rearing in the lab. We show that asexual mites retain seemingly functional copulatory and sperm storage systems, indicating that these lineages have relatively short evolutionary lifespans. One North American species, Thyreophagus ojibwe, was found in association with the native American chestnut Castanea dentata, suggesting a possibility that this mite can be used to control chestnut blight in North America. We also provide a diagnostic key to females, males, and heteromorphic deutonymphs of the Thyreophagus species in the world.

The genus Thyreophagus is distributed worldwide, containing species occurring in stored food, house dust, bark, subcortical habitats, scale insect associations, and nests of wasps and bees. As species of this genus prefer concealed habitats, the actual species diversity is currently underappreciated. In addition, some described taxa are poorly known and their species boundaries are not entirely clear. Only a few species are known from both adult and deutonymphal stages. Using high-resolution light microscope and scanning electron microscopy, we describe a new partenogenetic species, Thyreophagus calusorum sp. n. from Florida (USA) based on adult stage (female) and heteromorphic deutonymph. This species was reared in the lab and its morphological variation was also studied. We did not find any substantial variation in the shape of the female spermatheca, but in the heteromorphic deutonymph, we did find extensive variation in the shape of tibial setae hT I (a taxonomically important character). Furthermore, we summarized taxonomic data and compiled an annotated checklist of species of Thyreophagus, with 35 species-level taxa. We clarified the following nomenclatorial questions: type species designation in Monieziella Berlese, 1897 was done by A. Berlese in G. Leonardi 1900 (Tyroglyphus entomophagus Laboulbène) not by A. Jacot (1936) as it was though previously; Monieziella mali Berlese, 1897 is an unjustified emendation and junior objective synonym of the name Acarus malus Shimer, 1868, currently Hemisacoptes malus (Shimer, 1868). Three subspecies of Thyreophagus were elevated to the species status due to their distinct morphology: Thyreophagus italicus Vacante, 1989, stat. nov. (=Thyreophagus entomophagus italicus Vacante, 1989); Thyreophagus mauritianus (Fain, 1982), stat. nov. (=Michaelopus gallegoi mauritianus Fain, 1982), and Thyreophagus ponticus Kadzhaya, 1973, stat. nov. (=Thyreophagus entomophagus ponticus Kadzhaya, 1973).