Tangle-Web Spiders
Description
This family of spiders is large and diverse, and is also known by the common names “cobweb spiders” and “comb-footed spiders”. Only the latter accurately describes the entire family, due to a comb-like structure of bristles on their fourth leg. The other names refer to messy-looking space webs that most species create; however, members of this family actually create a variety of web forms.
The most famous members of this family are the so-called widow spiders of genus Latrodectus, specifically the black widows. Certain widow spiders are medically significant: their venom can significantly harm or even kill a human. Frustratingly, they also have an unusual affinity for human structures, giving us a true cause for wariness. Always use caution around any widow spider, and any bite by a widow spider should be seen by a trained medical professional.
That said, the widow spiders (especially of North America) are not aggressive and rarely bite humans. Even if one is bitten, serious damage is unlikely and medical treatment is rarely necessary. The primary treatment is pain relief.
Species
- Latrodectus geometricus (3 images)
- Theridion murarium (2 images)
Latrodectus geometricus
"Brown Widow Spider"
Description
This spider is reported to have highly variable coloration, but is typically yellow-brown or tan. The signature hourglass can range from yellow to red. Typical of a widow spider, this species is hairless and has long, delicate legs.
Notes
Native to Africa, this species has been introduced to Europe and North America by humans. This species may have painful venom, but its bite is not as dangerous as that of a black widow. Some research indicates that brown widows are displacing native western black widows in southern California, to the possible benefit of humans (see Journal of Medical Entomology).
Images of Brown Widow Spider
Theridion murarium
Description
Females have a very large, nearly spherical opisthosoma. First legs are longer than others. Prosoma is primarily tan to red. Legs are pale with tan or dark bands, with medium hairs. Opisthosoma is speckled brown with a wide, pale median band bordered by thick dark lines running the entire length on the anterior side.
Notes
This genus may be very difficult to confidently identify without microscopic examination of genitalia. In the particular specimen I've photographed, I got no clear shots of the prosoma, so identification can't be certain.
Images of Theridion murarium
