Porcellio laevis Latreille, 1804


GB IUCN status: Least Concern
GB rarity status: Nationally Scarce

ID Difficulty



A large woodlouse (to 20 mm), but differs from other Porcellio spp. in having a smooth dorsal surface.  In the male the uropods are elongated and 'spear-shaped'.  The combination of two flagella segments and two pairs of pleopodal lungs (typical of all Porcellio spp) distinguishes it from Oniscus asellus.
It can be confused with Porcellio dilatatus or even the ball-rolling Cylisticus convexus.
Mark Telfer
Keith Lugg
Keith Lugg
R.E. Jones
Jim Flanagan
J.P. Richards

Distribution and Habitat

Although uncommon, it has been widely recorded across Britain and Ireland. However, there seem to be very few modern records, and although probably under-recorded it does seem to have undergone a dramtic decline throughout the 20th century (Harding, 2016). 

It is principally associated with synanthropic habitats, such as old mature gardens, stables or dairy farms.  It should be sought within well-rotted compost heaps and dung heaps or under pieces of manure, straw and other debris, wherever some moisture has been retained.  Typically, it is associated with Porcellionides pruinosus and Porcellio scaber (and P. dilatatus at some sites).

This summary is based on the detailed account in Gregory (2009).



Harding, P.T. (2016) Is Porcellio laevis (Latreille) declining in Britain and Ireland?  Bulletin of the British Myriapod & Isopod Group 29: 23-27.

Gregory, S. (2009) Woodlice and Waterlice (Isopoda: Oniscidea & Asellota) in Britain and Ireland.  Field Studies Council/Centre for Ecology & Hydrology.



BRC Code