Soil-dwelling predatory mite

Stratiolaelaps scimitus
(formerly Hypoaspis miles)

Stratiolaelaps scimitus is a soil-dwelling predatory mite, the adults of which can be up to 1 mm long. They are a pale beige/brown in colour, with a darker ‘dorsal shield’ that tapers
towards the rear and covers most of the upper surface; the immature stages are generally paler in colour.

All life stages of this mite are found mainly in the top 1—2 cm of the soil or growing media; they are very rarely found on the above-ground parts of plants. The minute white, oval eggs  are Iaid on the soil surface and hatch into six-legged larvae that subsequently pass through two eight-legged nymphal stages. Adults and nymphs will feed not only on the larvae of fungus gnats, but also on other small, soil-dwelling mites and insects (including the young  larvae of other fly species, the pupae of thrips that are found in the soil (e.g. those of the western flower thrips (Frankliniella occidentalis)), springtails, and also some nematode
species.

Stratiolaelaps scimitus can survive in temperatures ranging from 12 to 30°C (54—86°F), but activity drops rapidly when sail temperatures fall below 15°C (59°F). The optimal temperatures for population growth are 20—25°C (68—77°F). At 20°C, the life-cycle
(egg to adult) is completed in approximately 18 days.  Adult longevity depends on both temperature and prey availability: in the absence of prey, this species is capable of surviving for approximately weeks (as long as water is present), and longer when adequate food is available.