Blue-Black Garden Slug - Arion hortensis


25 - 35mm. This slug belongs to a species-complex called the Arion hortensis group, which is comprised of Arion hortensis, A. owenii and A. distinctus. All have a yellow/orange sole. Though similar, most specimens can be identified to species with care. Arion hortensis is generally black with contrasting paler sides near to the sole and with few gold speckles on its tubercles. The tentacles are dark grey and translucent.

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.

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.

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

Most common on cultivated land, but also found in woods and gardens.

Life History

Eats any plants near the ground, and is a serious pest of strawberries, lettuces and seedlings.

UK Status

Common and widespread in Britain.

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