False Widow (Steatoda nobilis)

The False Widow is a species of dark-colored spiders that gets its name because of its strange resemblance to the infamous and venomous black widow spider. However, instead of being nearly aggressive, the false widows are rather shy, choosing to flee if an intruder attacks their web, and might only sting when cornered.

Physical Description and Identification

Adults

Size: As a sexual dimorphism, the female of the species is larger than the male, with the former being around 15 mm, while the latter, up to 10 mm in length.

Color: The abdomen of these creatures is dark brown with cream-colored markings, while the eight legs are reddish orange.

Other Characteristic Features: Like other members of the genus Steatoda, these creatures have a bulbous abdomen, although the body of the male is somewhat thinner and more elongated than the females. Also, this species has very poor eyesight.

Eggs

The female false widow spiders can lay three or even more sacs of eggs or cocoons between May and July, with each sac contain more than 200 or more eggs. The eggs are pale yellow to cream in color.

Spiderlings

The baby spiders hatch out from the eggs within 2 to 4 months. Just like the adults, all the stages of metamorphosis of the juvenile spiders can be seen in different human-made structures, round the year.

The Web

False Black Widow Spider makes a cobweb which is rather irregular in shape and is made up of a tangle of sticky silk fibers. It mostly depends on the vibrations made by an approaching enemy, which reaches the spider through the webs.

Black Widow Spider Bite: How Poisonous are they

They do have venom, but it is not fatal like that of the black widow. And as mentioned before, they are more likely to run away than jump at you in case of a confrontation. However, the false widow can inflict an extremely painful bite if they are scared or disturbed.

When bitten, the victim usually does not feel it right at the moment, but within around 15-20 minutes, the affected part becomes warm, turns red, and swell locally, developing a weal, often with a tingling feeling.

A pair of puncture wounds can also be seen in the area, as it turns somewhat pale blue within a few hours. However, the symptoms then gradually begin to withdraw, usually with some minor medication.

Quick Facts

Lifespan	Females can reportedly live for up to six years, but mostly die after laying the first egg sac; Males can live for up to 18 months, but they usually die shortly after their first mating
Distribution	Originally from the Canary Islands and Madeira, but now extensively found (as an introduced species) in parts of USA, England, as well as in Ireland, France, Spain, Italy and Portugal
Habitat	Primarily around human-made structures in the bark of trees, walls, fences, gardens, under rocks and wood, but rarely indoors
Common predators	Birds, toads, lizards, shrews, centipedes, scorpions, etc.
Diet	Commonly insects, other species of invertebrates including other smaller spiders

Did You Know

• The bulbous abdomen of the arthropod is often compared to the shape of a skull.
• Scientists claim that the increase in the population of the false widow in the UK is a result of global warming.
• It is said to be one of the few spiders whose bite (and the resultant release of venom) is medically important for humans.
• The first sighting in the southern hemisphere was reported in Chile in January 2016.
• In the recent past, in October 2018, four schools in the east of London were shut down temporarily because of infestations by false widow spider.

Image Credits: Nhm.ac.uk, imgs.heart.co.uk, I2-prod.leicestermercury.co.uk, C1.staticflickr.com, Cdn.images.dailystar.co.uk, I2-prod.mirror.co.ukI