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False Black Widow (Steatoda grossa)

The False Black Widow spider is part of the Steatoda genus and is frequently confused with the more dangerous Black Widow Spider. Known by various names, including ‘cupboard spider’ and ‘brown house spider’ in Australia, this species sometimes earns the label of a pest in certain areas. Learn more interesting facts about this misunderstood spider here.

Scientific Classification

False Black Widow

Physical Description and Identification

Adults

  • Size: Females are typically larger than 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 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 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 mature enough to separate.

Are False Black Widow Spiders Venomous?

Yes, False Black Widow spiders are venomous, but their venom is less potent than that of the true Black Widow spiders.

Can False Black Widow Spiders Bite?

Yes, False Black Widow spiders can bite humans, but their bites are usually less severe than those of the true Black Widow spiders. While they do have venom, it’s not highly potent to humans. If bitten, a person might experience mild pain, similar to a wasp sting, lasting for up to twelve hours.

False Black Widow Spider Web
False Black Widow Spider

Ecological Importance and Behavior of False Black Widow

The False Black Widow spider plays a pivotal role in controlling pest populations, helping to maintain ecological balance. Their webs capture and reduce the number of flying insects, which could otherwise become nuisances or spread diseases. Their nocturnal nature and penchant for secluded spaces mean they are seldom seen, though they are hard at work behind the scenes.

Natural Predator: Their list of natural predators is diverse, ranging from large lizards and birds of prey to other spider species. These predators help keep the False Black Widow’s population in check, preventing overpopulation and ensuring a balanced ecosystem.

Prey-Predator Dynamics: The dynamics between the False Black Widow and its predators are complex and integral to the stability of their shared habitats. Their venom, while not highly potent to humans, serves as a vital defense mechanism against potential threats, aiding in their survival.

Relationship with Humans: While their venom is not highly potent to humans, bites can occur, typically resulting in mild pain similar to a wasp sting. However, their role in controlling insect populations is beneficial to humans, showcasing the importance of coexistence and understanding these creatures better. Educating the public about the False Black Widow spider, differentiating it from its more dangerous relative, and highlighting its ecological benefits can foster a harmonious relationship between humans and these arachnids.

Quick Facts

LifespanWhile the females can live for up to 6 years, the males can live for 1.5; however, they mostly die shortly after mating
DistributionNorth America, Australasia, and Europe
HabitatCosmopolitan areas around or close to human habitats
Common predatorsLarge lizards, invertebrates including spiders of other species, and birds of prey, depending on their range
DietInsects, 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 bite the protagonist Peter Parker.

In conclusion, the False Black Widow spider, despite its menacing name, is a crucial player in its ecosystem, aiding in pest control and maintaining balance.

The Dark Comb Footed Spider

The False Black Widow spider is part of the Steatoda genus and is frequently confused with the more dangerous Black Widow Spider. Known by various names, including ‘cupboard spider’ and ‘brown house spider’ in Australia, this species sometimes earns the label of a pest in certain areas. Learn more interesting facts about this misunderstood spider here.

False Black Widow

Physical Description and Identification

Adults

  • Size: Females are typically larger than 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 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 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 mature enough to separate.

Are False Black Widow Spiders Venomous?

Yes, False Black Widow spiders are venomous, but their venom is less potent than that of the true Black Widow spiders.

Can False Black Widow Spiders Bite?

Yes, False Black Widow spiders can bite humans, but their bites are usually less severe than those of the true Black Widow spiders. While they do have venom, it’s not highly potent to humans. If bitten, a person might experience mild pain, similar to a wasp sting, lasting for up to twelve hours.

False Black Widow Spider Web
False Black Widow Spider

Ecological Importance and Behavior of False Black Widow

The False Black Widow spider plays a pivotal role in controlling pest populations, helping to maintain ecological balance. Their webs capture and reduce the number of flying insects, which could otherwise become nuisances or spread diseases. Their nocturnal nature and penchant for secluded spaces mean they are seldom seen, though they are hard at work behind the scenes.

Natural Predator: Their list of natural predators is diverse, ranging from large lizards and birds of prey to other spider species. These predators help keep the False Black Widow’s population in check, preventing overpopulation and ensuring a balanced ecosystem.

Prey-Predator Dynamics: The dynamics between the False Black Widow and its predators are complex and integral to the stability of their shared habitats. Their venom, while not highly potent to humans, serves as a vital defense mechanism against potential threats, aiding in their survival.

Relationship with Humans: While their venom is not highly potent to humans, bites can occur, typically resulting in mild pain similar to a wasp sting. However, their role in controlling insect populations is beneficial to humans, showcasing the importance of coexistence and understanding these creatures better. Educating the public about the False Black Widow spider, differentiating it from its more dangerous relative, and highlighting its ecological benefits can foster a harmonious relationship between humans and these arachnids.

Quick Facts

LifespanWhile the females can live for up to 6 years, the males can live for 1.5; however, they mostly die shortly after mating
DistributionNorth America, Australasia, and Europe
HabitatCosmopolitan areas around or close to human habitats
Common predatorsLarge lizards, invertebrates including spiders of other species, and birds of prey, depending on their range
DietInsects, 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 bite the protagonist Peter Parker.

In conclusion, the False Black Widow spider, despite its menacing name, is a crucial player in its ecosystem, aiding in pest control and maintaining balance.

The Dark Comb Footed Spider