Boettgerilla pallens (Simroth, 1912)
Not very sensitive to environmental conditions. In Britain the species is assumed to have excellent powers of dispersal and is still rapidly spreading (Kerney 1999: 153).
Feeding is seldom intensive; the slug usually takes a few bites and moves on. .
Up to 60 x 3 mm.
W Europe (not in central and N Scotland, Hebrides, Orkney and Shetlands) to Caucasus region, introduced to British Columbia.
Type Locality: Georgia: Abkhasia, Gudalty.
Humid forests at slopes and in river plains, on calcareous substrate, usually in quite natural habitats, occasionally also in gardens and disturbed habitats. In Switzerland in up to 1600 m altitude, usually below 700 m. Subterranean, slug is adapted to moving through earthworm burrows and similar spaces in soil, 2-20 cm (maximum up to 60 cm) below the surface.
Mating and egg-laying during late summer and into autumn in Britain (October in Germany), and eggs are laid as several 1-6 egg clutches 9-27 cm deep below surface. Adults survive egg-laying but die shortly after. Juveniles hatch after 20-22 days at 17 °C (in Germany), between October and December (in Britain). Juveniles turn colour from white to grey in May-June.
Feed on soft plant tissues, earthworm faeces, detritus, arionid eggs.
Considered as a pest in European greenhouses and gardens. Feeds on soft plant tissues.