Greenhouse Slugs Ambigolimax valentianus and A. parvipenis (prev. nyctelius)

Until 2022, it was thought that there were two Ambigolimax species of slug in the UK, both invasive from imported plants: the Greenhouse Slug, A. valentianus, thought to have originated in Spain, and the Balkan Three Band, A. nyctelius, thought to have originated in Eastern Europe. Both have two dark lines at the mantle which may continue down the body, with other dark lines and/or mottling present or absent. Maximum length is sme 8 cm. Ambigolimax species cannot be reliably differentiated by external, visual feautures.

Studies in 2014 renamed the alledgedly Balkan slug as A. parvipenis, the Three Band. (Another from Edinburgh Royal Botanic Gardens which had been thought the same species, was renamed A. waterstoni). In 2022 it was confirmed that the East European slug previously also thought the same was a different genus, Lehmannia carpatica.

Both the Greenhouse and Three Band Ambigolimax Slugs are invasive through the UK, much of Europe and elsewhere via imported plants, can live outside in warm or temperate climates and often co-occur at the same sites. Mainly nocturnal, they eat leaves, plants and other slugs (including cannibalism).