MolluscIreland - land and freshwater
  • Deroceras (Deroceras) laeve (O. F. Müller 1774) Marsh slug
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Deroceras (Deroceras) laeve
© Dr Roy Anderson
Deroceras (Deroceras) laeve
© Dr Roy Anderson
Deroceras (Deroceras) laeve
© Dr Roy Anderson

Map hosted by the National Biodiversity Data Centre, Waterford
To view the species profile on Biodiversity Maps and access the live map, please click on the map.


A small brown to dark brown slug with a brown sole and inconspicuously marked breathing pore. Found on marshy streambanks, lakeshores, fens and wetlands of all kinds to moderate altitudes.

Key characteristics

  • A small, brown to dark brown slug often with scattered darker flecks; paler, greyish forms occur widely in horticulture (see main photo)
  • Mucus colourless
  • Sole brown
  • Keel short and truncate
  • Respiratory pore not pale-ringed
  • Respiratory pore towards the rear of the mantle


15-25 mm.

World Distribution

A very widely distributed mollusc. Found naturally across the whole of Europe into Siberia as far east as the pacific and into northern North America. Distribution type: Circumpolar Wide Temperate (66).

GBIF distribution map [open in new tab]

Irish Distribution

Ubiquitous in wet places but not in very acid bogs or at high altitude.


  • Found on wet ground of all kinds except the most acid or exposed
  • Amphibious, surviving well for periods under water, as during flood events
  • Occurs as a pest in heated greenhouses and horticulture generally

Red List status

  • Least concern (lc).

Wikipedia link

Wikipedia page for Deroceras laeve

 Anderson, R., (2016). Deroceras (Deroceras) laeve (O. F. Müller 1774). [In] MolluscIreland. Accessed on 2024-03-02.