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Sowbug (Oniscus spp.)


Detailing the physical features, habits, territorial reach and other identifying qualities of the Sowbug.

 Updated: 3/12/2019; Authored By Staff Writer; Content ¬©www.InsectIdentification.org




Small, armored Sowbugs may go by many other names, but Pillbug and Roly Poly are not one of them.



Sowbugs are small, crawling Isopods, not insects. They cannot fly and do not sting. They are shaped like a bean and have many small legs hidden under their gray segmented armor plates. They are sometimes likened to a mini-armadillo. Sowbugs, however, do not roll up to protect themselves, like their similar-looking relatives, Pillbugs. To differentiate between these two types of Isodpods, look for two small tail-like appendages at the rear end. Sowbugs have them; Pillbugs do not. Sowbugs also have two pairs of antennae, though the second set is not easily visible.

Like Pillbugs, however, they can be found under stones, large rocks, logs, leaf litter, compost, mulch, and wood stacks. In fact, another name for a Sowbug is Woodlouse. They scavenge for decomposing organic debris in these areas. It is not unusual to see a few under the same stone or log, all searching for food. They prefer moist areas and head toward darker, more humid areas if displaced. Infestations are not likely and they are not considered a nuisance. If any find do their way indoors, they are unlikely to live long unless they find a damp, cool place. Removing debris and maintaining a dry interior will reduce the likelihood of seeing them inside.




Taxonomic Hierarchy
Kingdom: Animalia
  Phylum: Arthropoda
    Class: Malacostraca
      Order: Isopoda
        Family: Oniscidae
          Genus: Oniscus
            Species: spp.
Identifying Information
Scientific Name: Oniscus spp.
Other Name(s): Woodlouse, Woodlice
Category: Isopod
Size (Adult; Length): 6mm to 12mm (0.23in to 0.47in)
Colorwheel Graphic Colors: gray
Descriptors: armor, plates, armadillo, legs, shell, crawling
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Territorial Reach (A-to-Z)
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
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Alberta
British Columbia
Manitoba
New Brunswick
Newfoundland and Labrador
Nova Scotia
Ontario
Prince Edward Island
Quebec
Saskatchewan
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Mexico
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.