Triangulate cobweb spider
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| Steatoda triangulosa C. A. Walckenaer, 1802 |
The Triangulate cobweb spider (scientific name: Steatoda triangulosa; also called the triangulate bud spider) is a common house spider in the genus Steatoda. As the name indicates, it is well-known for the triangle-shaped pattern on the dorsal side of its abdomen.
[edit] Description
The adult female triangulate cobweb spider is 1/8 to 1/4 inch long (3 mm to 6 mm), with a brownish-orange cephalothorax and yellowish legs. The round, bulbous abdomen is brown in color, with a series of white or yellow triangle-shaped spots found on the dorsal (back) side of the abdomen, and other markings on the sides. .
The triangulate cobweb spider is known to prey on many other types of arthropods, including ants (including fire ants, other spiders, pillbugs, and ticks. It preys on several other spiders believed to be harmful to humans, including the hobo spider and the brown recluse.
The egg sac of the triangulated cobweb spider is made from loosely woven silk, and is about the same size as the spider itself. Each egg sac contains approximately 30 eggs.
[edit] Habitat and range
In common with other members of the Theridiidae family, S. triangulosa constructs a cobweb, i.e., an irregular tangle of sticky silken fibers. As with other web-weavers, these spiders have very poor eyesight and depend mostly on vibrations reaching them through their webs to orient themselves to prey or warn them of larger animals that could injure or kill them. They are not aggressive. Other, larger members of the Steatoda genus do have medically significant bites, but there are no recorded bites or envenomations by this spider.
S. triangulosa is a cosmopolitan species, and is found in many parts of the world, including all three coasts in North America, in southern Russia and New Zealand, and in Europe. The spider is believed to be native to Eurasia. This species is primarily a house spider, and builds webs in dark corners of buildings and other man-made structures.
[edit] External links
- The World Spider Catalog
- University of Arkansas Arthropod Museum Notes: Triangulate cobweb spider
- http://www.puyallup.wsu.edu/plantclinic/resources/pdf/pls107steatodaspider.pdf
- Penn State University Dept. of Entomology: Commonly Encountered Pennsylvania Spiders
- Levi, H.W. 1957. The spider genera Crustulina and Steatoda in North America, Central America, and the West Indies (Araneae, Theridiidae). Bull. Mus. Comp. Zool. 117(3):367-424
- Descriptions of four Steatoda species found in New Zealand
- pictures
- Hobospider.com: Steatoda spiders as competitors/predators of the hobo spider
