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Brown Widow (Latrodectus geometricus)


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

 Updated: 2/13/2018; Authored By Staff Writer; Content ¬©www.InsectIdentification.org




The Brown Widow is a more timid relative to the well-known and dangerous Black Widow, and though it is less toxic, its bite can pack a punch.



The moment the bright orange hourglass on her belly is visible, most people recognize this spider as a type of Widow. The overall brown/gray color and smaller size is standard for a Brown Widow. A black and white (or ivory) geometric pattern is visible on the dorsal (back) side of the abdomen. Legs are two-toned with wide bands of black and brown along the length of each one. It is likely that an observer will see her egg sac before seeing the female that made it. Egg sacs look like small, spiky golf balls. Other Widow spiders have smooth egg sacs.

Brown Widow spiders are native to Africa and have made a home in North America, most recently in California since 2003. The number of Brown Widow sightings in that state have led to research on the effect their presence is having on the native Black Widow population. They successfully compete for space and resources and seem to be outnumbering them in many areas.

While Brown Widows are venomous (as almost every spider is), their venom is not as toxic as the Black Widow because they are smaller-sized and transmit much smaller doses. The good news is that Brown Widows are extremely shy and prefer to flee from danger, rather than strike at the threat. Females protecting silky white egg sacs are most likely to bite since a retreat may cost them their eggs. Cornered or trapped spiders are also more apt to bite as a means of potential escape. Bites, though rare, are painful and victims would be wise to visit a medical professional in the uncommon case of a potential sensitivity to the venom.

Compared to other spiders in the Widow family, this is the least dangerous and most docile. They are becoming more abundant in places where humans tread. Silk webs can be built near houses, garages, sheds, parking lots and even gas stations. Despite the diminished risk of a bite, it is still wise to keep clear of the Brown Widow and leave it undisturbed. The Brown Widow bears a classic warning mark; it is best that we take heed.




Taxonomic Hierarchy
Kingdom: Animalia
  Phylum: Arthropoda
    Class: Arachnida
      Order: Araneae
        Family: Theridiidae
          Genus: Latrodectus
            Species: geometricus
Identifying Information
Scientific Name: Latrodectus geometricus
Other Name(s): Grey Widow, Brown Black Widow, House Button Spider, Geometric Button Spider
Category: Spider
Size (Adult; Length): 3mm to 17mm (0.12in to 0.66in)
Colorwheel Graphic Colors: brown, black, orange, , yellow, ivory, gray
Descriptors: hourglass, spot, biting, venomous, banded, striped
Territorial Map
Alaska  
Hawaii  
Prince Edward Is.  
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Territorial Reach (A-to-Z)
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delware
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
Canadian National Flag Graphic
Alberta
British Columbia
Manitoba
New Brunswick
Newfoundland and Labrador
Nova Scotia
Ontario
Prince Edward Island
Quebec
Saskatchewan
Mexican National Flag Graphic
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.




Spider Anatomy
Graphic showing basic parts of spider anatomy
1
Legs: Spiders have four pairs of legs and these are attached to the cephalothorax.
2
Pedipalps: Small appendages near the mouth used as taste and smell organs.
3
Cephalothorax: Contains eyes, head, mouthparts, and legs.
4
Abdomen: Contains various organs related to digestion, reproduction, and web-making.
5
Spinnerets: Used in the production of spider silk for fashioning webs or catching prey.
NOTE: Unlike insects, spiders have both an endoskeleton (internal) and exoskeleton (external).