Dusky Slug - Arion subfuscus


Length: 50 to 70 mm. This slug comes in various shades of yellows and browns. An important identification feature is the body mucus which stains orange on your finger (stroke the tail end). The body contracts to an elongate dome. It usually has two dark lateral bands, fairly high on the body. The sole is pale and the sole fringe blends in with the body.

Similar Species

There are two very similar but rare slugs that could be confused with Arion subfuscus, but neither has been recorded in Leicestershire and Rutland. Arion fuscus has been found at four UK sites, including one in Nottinghamshire. Arion iratii is only known from South Wales. Dissection is needed to separate these species.

Juveniles of Arion flagellus also look similar but are easily distinguished by the large, rough-looking tubercles. Arion subfuscus has particularly fine tubercles giving it a much smoother appearance.

Identification difficulty

Various well vegetated areas, including woodland and grassland.

When to see it

All year.

Life History

They eat leaves, stems, flowers and fruits close to the ground like strawberries and tomatoes and will also eat fungi. Because of this catholic diet, it doesn't cause much damage to live plants so is not much of a pest.

UK Status

Very common and widespread across the whole of Britain, perhaps less so in East Anglia.

VC55 Status

Common in Leicestershire and Rutland.

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Leicestershire & Rutland Map


Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map