Noble false widow

Description

Steatoda nobilis is a spider in the genus Steatoda, known in the United Kingdom as the noble false widow and is often referred to as the false widow.As the common name indicates, the spider superficially resembles and is frequently confused for the black widow and other spiders in the genus Latrodectus. It is a medically significant spider, where in England it has a reputation as one of the few local spider species that is capable of inflicting a painful bite to humans,with most bites resulting in symptoms similar to a bee or wasp sting. S. nobilis is spotted all year round, both indoors and outdoors in a variety of habitats including cacti, roadside cuttings, and demolished buildings.They prey on both vertebrates and invertebrates using an "attack wrap" strategy where silk is wrapped around the victim. Steatoda nobilis is native to Madeira and the Canary Islands from where it allegedly spread to Europe,and continued to spread to other parts of the world including the United States, Chile, Colombia and other countries. They are one of the world's most invasive species of spider. Steatoda nobilis has a brown bulbous abdomen with cream coloured markings that are often likened to the shape of a skull.Their legs are reddish-orange.Both female and male S. nobilis can be distinguished from other spiders of the same genus by their large size and typical colouration. Females range in size from about 9.5 to 14 mm in size, while males are 7 to 11 mm.The largest females are 13.7 mm in size, while the largest males can be 11.66mm in size. The males can be distinguished by their conformation of the palp and by their ventral abdominal markings. The females can be distinguished by their epigyne.The variation in size, shape and markings that have been observed is not thought to be due to location. Spiders found centimeters apart and siblings born from the same egg sac can look very different. Male and female juvenile spiders are indistinguishable from each other.