Limax maculatus (Kaleniczenko, 1851) (Mollusca, Limacidae) New to Worcestershire

By P.F.Whitehead

At the end of May 2000, Mrs S. Ravenscroft of Little Comberton (SO94) found three "very large" slugs eating vegetables placed in a bowl for a pet rabbit. The slugs, which were some 14 cms long when extended, were duly photographed and these were passed to me for comment. It was immediately apparent that the animals in question were the limacid (keeled with a characteristically-patterned internal shell) slugs Limax maculatus (Kaleniczenko, 1851), a species for which, hitherto, there were scarcely any inland records in central and southern Britain. The occurrence of this species in Worcestershire is therefore of some significance (or rather was, since a Blackbird rapidly despatched two of the photographed specimens).

On 2 September 2001 a second site for L. maculatus was confirmed when a smaller specimen was found amongst tipped rubble, wood and fabric at the back of a town garden in Pershore town (SO94). It would appear, therefore, that like numerous other terrestrial mollusc species before it, L. maculatus is beginning to expand its range following in modern "white man's footsteps." Indeed it may now be doing so via the direct agency of humankind.

Limax maculatus does not require to be dissected for its identity to be confirmed. The principal confusion species is Limax flavus Linnaeus, 1758. This slug is positively culture-favoured to the extent that it is closely associated with human habitation sites, may occur inside houses, and is frequently found in drains. However, populations of L. flavus may also rarely occur in open country, most usually in association with dead fungoid trees. L. flavus is essentially bright olive-green, generously flecked with yellow, although it can occur in darker forms. L. maculatus is generally dull brownish green, usually with a network of large pale coffee-coloured blotches over the dorsal surface, most especially on the mantle. L. flavus may appear more glistening than L. maculatus, especially when irritated, due to its more transparent body-mucous.

Since L. maculatus now occurs throughout Ireland, where L. flavus is very rare, it will be interesting to observe the mutual fortunes of the two species in England if L. maculatus continues to expand its range. Details of these records have been lodged with the National Recorder for the group.

Limax maculates at Little Comberton. Photo S & J Ravenscroft


On 7 November 2001 a specimen of Limax maculatus was found in a rural garden at Barton, Warwickshire, SP15, VC38, to which vice-county it is new. The background colour of this specimen was somewhat more grey than others seen, on which a network of dark olive-green mottling was super-imposed.

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