Irish Yellow Slug - Limacus maculatus


This medium to large (70 to130 mm long) slug is green to dull yellow with darker blotches. It has grey to blue-grey tentacles and colourless to yellow or orange slime. It may have a yellow stripe at the tail end but this doesn't extend more than half way along the body, and is usually much shorter.

Like many slugs it can be quite variable in colour and the spotting pattern is always unique. The mantle texture looks like a fingerprint when the light is at the right angel. Juveniles are very dark and can appear almost black with the spots hard to see.

Similar Species

Limacus flavus, the Yellow Slug, is very similar but is a brighter yellow with smaller spots and blotches. The tentacles are blue, rather than the blue-grey of L maculatus. L. flavus has a yellow line along the keel that extends from the tail to around half the body length or beyond, though it may become broken into dashes. It is likely that Limacus flavus is extinct in Leicestershire and Rutland, having been replaced by L. maculatus.

Both Yellow Slugs are variable species, but they normally lives in colonies so it is helpful to look at several individuals to see the overall traits, though beware that they can live together.

Identification difficulty
Recording advice

Unless identified by a recognised expert, a photo is required. If the photo doesn't show the key ID features then in the comments box describe the size and identifying characters you have observed.


Damp places, sometimes under stones and logs. It is closely associated with man-made habitats and is a common garden resident where it can often be found in compost bins. It is also commonly found in houses and slug trails on the kitchen floor are often this species.

When to see it

All year round

Life History

This species has been expanding its range across Britain and seemingly replacing Limacus flavus along the way.

UK Status

It is expanding its range and now common and widespread.

VC55 Status

Common in Leicestershire and Rutland.

be our species champion

Leicestershire & Rutland Map


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

UK Map