Life history and behavior of mites in the genus Lasioseius (Acari: Mesostigmata: Ascidae) from grassland soils in Colorado, with taxonomic notes and description of a new species

Abstract

Lasioseius berlesei (Oudemans), Lasioseius youcefi Athias-Henriot, Lasioseius kinikinik n.sp., and Lasioseius confusus Evans were collected from grassland soils in Colorado. Lasioseius berlesei and L. youcefi are known only from the female, and for the first time in an ascid mite, we experimentally demonstrate that they reproduce by thelytokous parthenogenesis. Both species are omnivores that will feed on fungi and animal prey, and they share a multidenticulate ridge apposed to a groove on the paraxial faces of the chelicerae which appears to function as a mashing and filtering mechanism during mycophagy. Similar cheliceral structures are lacking in L. kinikinik n.sp. (described in this paper), a bisexual species that must mate to produce eggs, and does not feed on fungi. Diagnoses are presented for L. berlesei, L. youcefi, and L. confusus, and their sperm reception structures (spermatheca, etc.) are illustrated for the first time. Based on the study of type specimens, new morphological evidence, and rearings, we propose that (i) the previous synonymy of L. confusus with L. berlesei be rejected; (ii) Lasioseius mcgregori Chant, 1963 is a junior synonym of L. youcefi Athias-Henriot, 1959; (iii) L. scapulatus Kennett, 1958 is a junior synonym of L. dentatus (Fox, 1946); and (iv) L. furcisetus Athias-Henriot, 1959 is the correct name for L. penicilliger sensu Evans, 1958 and subsequent authors, not Berlese, 1916; L. lanciolatus Chant, 1963 is a junior synonym of L. furcisetus.