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False Black Widow (Steatoda grossa)

Like several spiders belonging to the genus Steatoda, the False Black Widow spider, too, is often mistaken for the rather deadly Black Widow Spider. This species is known in many a name like ‘cupboard spider’, the ‘dark comb-footed spider’, as well as the ‘brown house spider’ in Australia. In some parts within their range, they are considered as pests.

False Black Widow

Scientific Classification

Physical Description and Identification

Adults

Size: Females are typically larger than the males, measuring up to 15 mm, while the males usually do not exceed 10 mm.

Color: The entire body is purplish brown to black with pale markings in both the sexes.

Other Characteristic Features: While the females have round, bulbous abdomens, the males are rather thinner and more elongated, without a belly. They also bear fangs on their chelicerae (mouth part). They do not jump, but rather, build their own web and wait patiently for their prey to fall a trap in it.

False Black Widow Spider Size

Eggs

A healthy, adult female is capable of laying around three or even more egg sacs every year. A sac can contain anything between 40 and 100 eggs. The mother spider keeps guarding its eggs for many hours, or even several days at a stretch until they begin changing color and the time for them to hatch nears. The eggs hatch out in around a month from the time they are laid.

Spiderlings

Unlike the true black widow spiders, the baby false black widows have a dark coloration similar to their mothers when they emerge from the eggs. The mother guards the young ones until they are matured enough to separate.

How Poisonous is the False Black Widow Spider Bite

Despite their resemblance to the infamous black widow spider, this species has a rather harmless bite. They are not at all deadly, as they are mistaken to be. The fact is, these spiders do carry venom, but it is not particularly potent to humans, but are used only to capture their prey. Even if it bites a person, the only symptom that shows up is mild pain at the site that might radiate slightly in the surrounding areas, usually lasting for one to twelve hours. The bite is no worse than the sting of a wasp.

False Black Widow Spider Web
False Black Widow Spider

Quick Facts

Lifespan While the females can live for up to 6 years, the males can live for 1.5; however, they mostly die shortly after mating
Distribution North America, Australasia, and Europe
Habitat Cosmopolitan areas around or close to human habitats
Common predators Large lizards, invertebrates including spiders of other species, and birds of prey, depending on their range
Diet Insects, mostly the flying ones that usually get trapped in their cobweb
False Black Widow Male

Did You Know

  • Their resemblance to the dangerous black widow spider is but a mimicry that they use as a weapon to defend themselves from predators.
  • In the 2002 Sam Raimi-directed film Spider-Man, a specimen of the Steatoda grossa was used that bit the protagonist Peter Parker.
False Black Widow Female
The Dark Comb Footed Spider
Cupboard Spider

Image Credits: Animalcorner.co.uk, Haslemereherald.com, Falsewidowspider.org.uk, Nhm.ac.uk, lh5.ggpht.com, Bugguide.net,
Cdn-03.independent.ie, I.pinimg.com

Like several spiders belonging to the genus Steatoda, the False Black Widow spider, too, is often mistaken for the rather deadly Black Widow Spider. This species is known in many a name like ‘cupboard spider’, the ‘dark comb-footed spider’, as well as the ‘brown house spider’ in Australia. In some parts within their range, they are considered as pests.

False Black Widow

Physical Description and Identification

Adults

Size: Females are typically larger than the males, measuring up to 15 mm, while the males usually do not exceed 10 mm.

Color: The entire body is purplish brown to black with pale markings in both the sexes.

Other Characteristic Features: While the females have round, bulbous abdomens, the males are rather thinner and more elongated, without a belly. They also bear fangs on their chelicerae (mouth part). They do not jump, but rather, build their own web and wait patiently for their prey to fall a trap in it.

False Black Widow Spider Size

Eggs

A healthy, adult female is capable of laying around three or even more egg sacs every year. A sac can contain anything between 40 and 100 eggs. The mother spider keeps guarding its eggs for many hours, or even several days at a stretch until they begin changing color and the time for them to hatch nears. The eggs hatch out in around a month from the time they are laid.

Spiderlings

Unlike the true black widow spiders, the baby false black widows have a dark coloration similar to their mothers when they emerge from the eggs. The mother guards the young ones until they are matured enough to separate.

How Poisonous is the False Black Widow Spider Bite

Despite their resemblance to the infamous black widow spider, this species has a rather harmless bite. They are not at all deadly, as they are mistaken to be. The fact is, these spiders do carry venom, but it is not particularly potent to humans, but are used only to capture their prey. Even if it bites a person, the only symptom that shows up is mild pain at the site that might radiate slightly in the surrounding areas, usually lasting for one to twelve hours. The bite is no worse than the sting of a wasp.

False Black Widow Spider Web
False Black Widow Spider

Quick Facts

Lifespan While the females can live for up to 6 years, the males can live for 1.5; however, they mostly die shortly after mating
Distribution North America, Australasia, and Europe
Habitat Cosmopolitan areas around or close to human habitats
Common predators Large lizards, invertebrates including spiders of other species, and birds of prey, depending on their range
Diet Insects, mostly the flying ones that usually get trapped in their cobweb
False Black Widow Male

Did You Know

  • Their resemblance to the dangerous black widow spider is but a mimicry that they use as a weapon to defend themselves from predators.
  • In the 2002 Sam Raimi-directed film Spider-Man, a specimen of the Steatoda grossa was used that bit the protagonist Peter Parker.
False Black Widow Female
The Dark Comb Footed Spider
Cupboard Spider

Image Credits: Animalcorner.co.uk, Haslemereherald.com, Falsewidowspider.org.uk, Nhm.ac.uk, lh5.ggpht.com, Bugguide.net,
Cdn-03.independent.ie, I.pinimg.com

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