Spiders of the genus Steatoda belong to the spider family Theridiidae, or the cobweb weavers. Also known as Combfooted Spiders, this family includes a number of well known arachnids, including the American house spider, Parasteatoda tepidariorum, and the redback and widow spiders, Latrodectus spp.. Steatoda spiders are found throughout the world, in both temperate and tropical climates.
They are small to moderately small (3-9 mm) spiders with oval abdomens; they may be reddish, brownish or black, with most species exhibiting a white band at the front of the dorsal abdomen which may resemble a collar. These spiders construct a strong, irregular web, somewhat resembling the webs of widow spiders; this web is very sticky, making it a highly effective snare for hobo spiders which they are very good at catching. Steatoda Grossa, the False Widow spider is the most well known of the Steatoda spiders.
Found in cosmopolitan areas around the world, and on both coasts of the United States, Steatoda Grossa is a larger (9 mm) Steatoda which, as its common name suggests, may resemble a black widow spider (with no hourglass). Specimens can be reddish to purplish brown in colour, with pale yellow markings on the dorsal abdomen, but many specimens are so dark that these pale markings cannot be distinguished. Steadota/Steatoda grossa is a common and well known “house spider” in many areas, constructing its webs in and around buildings, rock walls, and other structures. It has long been known that the “false widow” will ensnare, kill and prey upon actual black widow spiders in its natural habitat. The bite of the common comb footed spider causes mild local pain unlike the redback/widow spiders whose bites should be treated immediately with antivenom, especially in a young child.
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Steatoda Grossa – UK
The False Widow spiders, Steatoda Grossa, belong to the genus, or group, called Steatoda . There are six species of Steatoda found in the UK including one introduced species, Steatoda nobilis.This group of spiders get their name because they look similar to the true black widow group of spiders, genus Latrodectus. However Steatoda are significantly less harmful to humans. Steatoda are shaped similarly to widow spiders, with round, bulbous abdomens. However, not all Steatoda species resemble widows – many have distinct coloring, and are significantly smaller than Latrodectus specimens. Some species of Steatoda actually will prey on widows, as well as other spiders which are considered hazardous to humans.
In common with other members of the Theridiidae family, the Steatoda spiders construct a cobweb, i.e., an irregular tangle of sticky silken fibres. 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, and most injuries to humans are due to defensive bites delivered when a spider gets unintentionally squeezed or pinched somehow. It is possible that some bites may result when a spider mistakes a finger thrust into its web for its normal prey, but ordinarily intrusion by any large creature will cause these spiders to flee. Some members of this genus do have bites which are medically significant in humans (such as S. grossa and S. nobilis), however bites by Steatoda species generally do not have any long-lasting effects.
S. nobilis is native to the Canary Islands but arrived in England in around 1870 through bananas sent to Torquay. In England it has a reputation as one of the few local spider species which is capable of inflicting a painful bite to humans – although this is a comparatively rare occurrence.
Steatoda Grossa – USA
Steatoda Grossa – Other Places
Steatoda triangulosa
The triangulate cobweb spider, Steatoda Triangulosa, is a common spider in the genus Steatoda. It is well known for the triangle-shaped pattern on the dorsal side of its abdomen.
Steatoda Nobilis
S. nobilis is native to the Canary Islands but arrived in England in around 1870 through bananas sent to Torquay. In England it has a reputation as one of the few local spider species which is capable of inflicting a painful bite to humans – although this is a comparatively rare occurrence.
Steatoda Paykulliana and Steatoda Bipunctata
Steatoda paykulliana is a species of false black widow spider in the tangle-web spiders family, native to the Mediterranean countries, Southern Europe and Western Asia. The species is named in honor of the Swedish naturalist Gustaf von Paykul.
Steatoda bipunctata is a species of cob-web spider, of the genus Steatoda, in the family Theridiidae. With a holarctic distribution, it is common in North America and Europe. It may be found in proximity to human structures, such as basements or sheds.
Other Steatoda Species
These are photos of other spiders that belong to the Steatoda sp. I couldn’t find an exact match for them but they are typical in body shape and markings of the Steatoda family. If anyone can ID them, please email me.
