Species of the Month December 2022

Green Cellar Slug (Limacus maculatus)


Green Cellar Slug is a relatively recently arrival in Britain, with the first records appearing during the 1970s. The species quickly spread, apparently displacing the native Yellow Cellar Slug (Limacus flavus) which has sharply declined during the same time frame. Both can be found in gardens, feeding on decaying plant material (Limacus are not considered pest species as they do not damage live plants).

Slugs are generally under recorded, probably due to their (contestable!) lack of charisma, but also because they can be a difficult group to identify. Fortunately the Green Cellar Slug is relatively straight forward to recognise, with only the Yellow Cellar Slug as a possibly confusion species. Both have yellow bodies with dark mottling and grey tentacles (eye structure). The Yellow Cellar Slug has a long yellow stripe running up the back, which is absent or very short in the Green Cellar Slug. The Royal Horticulture Society has an excellent visual guide to the two species (and Leopard Slug (Limax maximus) which is superficially similar) which can be downloaded here.

Green Cellar Slug is a nocturnal species, so the best way to find them is a torch lit hunt in the garden after dark. More photos and information about Green Cellar Slug is available on NatureSpot and the RHS website (the RHS research project is now ended but records are still useful for SEWBReC and the Conchological Society of Great Britain and Ireland).

Please include a photograph with your records to allow the national experts to verify your sighting (particularly if you are lucky enough to find a Yellow Cellar Slug, which is now very rarely seen).

Green Cellar Slug very likely to be found in gardens throughout south east Wales, however, it is very under recorded with just 149 records held at SEWBReC. You can view the 1km distribution for SEWBReC here and the 10km Wales wide distribution here.

If you spot Green (or Yellow) Cellar Slug during December (or at any other time of year), please send us the record, ideally via SEWBReCORD or the LERC Wales App. Instructions on how to submit records are available here.