Brown Soil Slug - Arion distinctus

Alternative names
Common Garden Slug
Description

Length to 30 mm. This slug belongs to a species-complex called the Arion hortensis group, which is comprised of Arion hortensis, A. owenii and A. distinctus. Arion distinctus is usually dark brown with numerous tiny gold speckles on its tubercles - best seen through a lens. All the species in this group have a pale yellow or orange sole and characteristic yellow-orange mucus. The animals have no keel. Contracted specimens are rounded in cross-section.

Similar Species

Arion distinctus - brown to grey, sometimes with a greenish tint and usually with many gold speckles on its tubercles. Tentacles dark grey and not translucent. The mantle stripe partly surrounds the breathing pore.

Arion hortensis - more contrasting black back and paler sides with fewer gold speckles on its tubercles. Tentacles dark grey but translucent, with a warm glow. The mantle stripe arches over the breathing pore.

Arion owenii  - tawny brown with contrasting dark lateral stripes and diffuse pigment along the back. Head and tentacles are black to purplish brown or warm red-black.

Identification difficulty
Habitat

This slug often inhabits disturbed sites (e.g., gardens, roadsides).

When to see it

All year round.

Life History

The common garden slug breeds throughout much of the year and can be a serious pest of gardens as they attack cultivated plants, fruit, tubers and bulbs. Slugs are hermaphrodites, meaning that individuals possess both male and female reproductive organs, but self-fertilisation does not occur. During courtship, members of a pair follow each other in circles, whilst feeding on their partner's mucus trail.

UK Status

Widespread and common in Britain.

VC55 Status

Common in Leicestershire and Rutland.

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Leicestershire & Rutland Map

MAP KEY:

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

UK Map