brickwork woodlouse

(Porcellio spinicornis)

Conservation Status
brickwork woodlouse
Photo by Greg Watson
  IUCN Red List

not listed


not listed


not listed


Brickwork woodlouse is a large, exotic woodlouse. It is native to Europe, where it is widespread and common. It was introduced into North America, where it is now naturalized. It occurs across southern Canada. In the United States it occurs from Maine to New Jersey, west to North Dakota and South Dakota, with a few scattered occurrences in the west. It is not uncommon in Minnesota. It favors dry areas with limey (calcareous) surfaces. It is found in limestone quarries, on limestone pavement, in loosely mortared walls, and often in human houses. It is sometimes found on the bark of apple, lime, and basswood trees, all of which have calcareous bark. It is active at night, when it can be found on the surface. During the day it remains concealed, often under a rock or log.

Adults are to (10 to 15 mm) in length. The body is oval in outline and more or less compressed above. It is rough or granular due to the presence of numerous rounded bumps (tubercles). It is yellowish with dark brown to almost black mottling, and a dark brown to almost black stripe in the middle (middorsal) bordered on each side by bright yellow markings. One imaginative describer likened the pattern to brickwork, and this is the source of this species’ common name.

The head is about twice as wide as long. It is fused to but not hidden under the first segment of the thorax. It has three lobes in front: a broadly rounded lobe in the center, and a longer, narrower, rounded lobe on each side. There are two widely spaced eyes. Each eye is a tight grouping of up to 30 dark-colored simple eyes (ocelli). The antennae are long. The end section of each antenna has two distinct segments. The first segment is a little longer than the second.

The thorax (pereon) is large and has seven segments of slightly unequal length. There is a single jointed leg on each side of each segment. The upper exoskeletal plate (tergite) on each thoracic segment and the first five abdominal segments is expanded on each side into a thin, flat, lateral extension (epimeron). The rear angle on each epimeron extends rearward. On the first thoracic tergite, the front angle on each side extends forward.

The abdomen (pleon) is much smaller and has six segments, all of which are distinct. The junction between the pereon and the pleon is smooth, not stepped. The lateral portions of the first two abdominal segment are concealed beneath the seventh thoracic segment. The third, fourth, and fifth segments have prominent, well developed, epimera. The last segment, the sixth, is called the telson. The telson is triangular and does not extend beyond the epimera of the fifth segment. On each side of the telson there is an elongated appendage, called a uropod. The uropods are lance-shaped and project well beyond the end of the body. On the under side of the abdomen there are just 2 pairs of pleopodial lungs. They appear as white dots on the first and second abdominal segments.

The legs are long relative to other families of woodlice.




Total length: to (10 to 15 mm)


Similar Species


Dry areas with limey (calcareous) surfaces; limestone quarries, limestone pavement, mortared walls, human houses, and the bark of apple, lime, and basswood trees.








Unlike pill woodlice (Family Armadillidae), brickwork woodlouse cannot roll into a ball.






Life Cycle




Juvenile Food




Adult Food




Distribution Map



24, 29, 30, 82.




Native to Europe





  Subphylum Crustacea (crustaceans)  
  Superclass Multicrustacea (typical crustaceans)  
  Class Malacostraca (malacostracans)  
  Subclass Eumalacostraca (decapods, isopods, and allies)  
  Superorder Peracarida (amphipods, isopods, and allies)  


Isopoda (Isopods)  


Oniscidea (woodlice, pillbugs, and rock slaters)  


Holoverticata (woodlice and pillbugs)  











Common Names


brickwork woodlouse

painted woodlouse










Alkaline; rich in limestone; containing a high proportion of calcium carbonate.



Simple eye; an eye with a single lens. Plural: ocelli.


Tergum; tergite

The upper (dorsal), hardened plate on a segment of the thorax or abdomen of an arthropod or myriapod. Plural: terga.



On plants and animals: a small, rounded, raised projection on the surface. On insects and spiders: a low, small, usually rounded, knob-like projection. On slugs: raised areas of skin between grooves covering the body.



On some crustaceans, a pair of appendages on the sixth and final abdominal segment. On lobsters and similar species, it forms part of the tail fan.






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I see this one before but the are usually Deceased this one was on the move. What is it?

    brickwork woodlouse   brickwork woodlouse  
    brickwork woodlouse   brickwork woodlouse  

Greg Watson

    brickwork woodlouse   brickwork woodlouse  





Andree Reno Sanborn
Porcellio spinicornis
Lloyd Davies
  Porcellio spinicornis  

Porcellio spinicornis Painted Woodlouse




Visitor Videos

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Other Videos
  Watching Brickwork'ers (Porcellio Spinicornis). I spy on isopods!
Isopod Corner

Oct 4, 2021

In this video we observe a colony of Porcellio Spinicornis "hard at work". Take a few minutes to watch these cute little isopods with some of my isopods.


  Dornfühlerassel (Porcellio spinicornis)

Jan 2, 2012

A special snowbug comes accross. Filmed at the 02.01.2012 in Brandenburg.

Eine Dornfühlerassel läuft über den Weg. Gefilmt am 02.01.2012 in Brandenburg

  Porcellio Spinicornis Stínka skvrnitá

Jun 22, 2015




Visitor Sightings

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Location: Central Minnesota

I see this one before but the are usually Deceased this one was on the move. What is it?

brickwork woodlouse  
  Greg Watson

Location: Reno Quarry Trail, Reno North Recreational Area

brickwork woodlouse  






Created: 7/6/2022

Last Updated:

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