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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.

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 spindly, yellowish legs. The round, bulbous abdomen is creamy in color, with parallel purply-brown zigzag lines running front to back. This distinctive pattern sets it apart from other theridiids in its area.

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.Cobweb spiders typically live on windows or in dirt areas, they eat for a margin of their day and spend hours developing their web, it does not break if it is woven well.If you have a cobweb spider on your window or somewhere you may notice that there are many dead insects below or in the web, which range from stinkbugs to other spiders, even wasps. it is small with a circular bottom and a fractal similar pattern on it. Their web is very strong, in fact if you see ones web and pull it you may find it difficult to break, because it weaves a very strong material.

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.