Cobweb Spiders: Theridiidae
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The Theridiidae, generally known as cobweb spiders or comb-footed spiders, are a large family of spiders covering approximately two dozen genera and a couple hundred species in the United States.
Most people would not give Theridiidae a second thought were it not for the presence of the widow spiders (Latrodectus genus) and their poisonous bites.
Many Steatoda species go by the name, false widow. Often the name refers to the spider's looks. From a distance, the body often appears dark, like the black widow spider.
Of course, just the name of the widow spider means that most people avoid all small dark spiders.
Picture two provides a close up view of a male false widow spider (Steatoda Grossa). The long front pair of legs have been cropped. With the legs extended, it measures approximately and inch and one-quarter in length.
Their bites are known to cause pain and discomfort for a small portion of the population, however for most people, their bite produces no side effects.
Picture three shows Steatoda nobilis, a native of the Canary Islands that has since been introduced to the southwest coastal region of Europe, including the southern areas of the UK. Because the British have little experience with biting spiders, its northern migration is causing a bit of a row in the local papers.
Thanks to AP in Essex for the picture and story. The picture is enlarged to show the spider's abdominal pattern, and it highlights the spider's long front legs.
The bites of other Theridiidae species are not categorized as poisonous, and apart from their medical prominence, the Theridiidae also consists of additional spiders of interest.
A social spider genus, Anelosimus, especially Anelosimus studiosus, a common species along the Southeast and Gulf Coast areas produce females who congregate in webs of local trees and shrubs, collectively protecting their egg sacs and rearing young spiderlings.
Marvel comics relates the tale of another Theriddidae claim to fame for the Achaeranea genus by confirming the fact that the common house spider (Achaearanea tepidariorum) bit Peter Parker, leading to his second career as Spiderman.
The top picture shows a species in the Enoplognatha genus. Outside the web, Theridiidae species can be initially identified by their round abdomens and long pair of front legs.
© 2008-2011 Patricia A. Michaels