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Western Black Widow (Latrodectus hesperus)

Have you ever heard about the Western Black Widow spider? It’s a special spider found mostly in the western areas of North America. They are closely related to the northern black widow. Stick around, and we’ll share some fun facts about this interesting creature!

Scientific Classification

Western Black Widow

Physical Description and Identification

Adults

  • Size: Females are 0.5 inches (15 mm) in length with a leg span between 1.5 and 2 inches (38.1 to 50.8 mm). Males are however smaller about 1/3rd the size of their female counterparts.
  • Color: They have a glossy black body(mostly the females)with red hourglass markings on the undersides of their abdomen, which can also be yellow or even white (which is rare though). The male spiders are not completely black but have shades of gray or light brown on their body. The hourglass pattern is present in the males too, though it is more orange than red and at times even yellow.
  • Other characteristics: The bottom half of the hourglass pattern is slimmer, while the top part is wide.
Western Black Widow Spider Size

Eggs

The eggs attached to the mother’s web are pear-shaped with their color being whitish-yellow or pear-shaped. In a particular sac, there are about 200 eggs that hatch within two weeks of being laid.

Western Black Widow Egg Sac

Spiderlings

Both the males and females have the same color, with the topside being gray or olive, striped in yellow or white. In the undersides of the spiderling’s abdomen, an hourglass pattern or two triangles facing opposite to each other may be seen.

The Web

The web resembles a cobweb made of strong, white silk, found under logs, rocks, big crevices, or cracks.

Western Black Widow Web

Are Western Black Widow Spiders Venomous?

Yes, Western Black Widow Spiders are venomous. Their venom is strong and helps them catch food.

Can Western Black Widow Spiders Bite?

Yes, Western Black Widow Spiders can bite. They might bite if they feel threatened. Their bite might result in sharp pain just like the pricking of a pin, while some can experience mild symptoms like swelling or redness.

Male Western Black Widow

Ecological Importance and Behavior of Western Black Widow Spider

These spiders are vital for controlling insect populations, preventing outbreaks of pest species. They exhibit unique behaviors, such as the males’ abdominal ‘drumming’ on females’ webs as a mating ritual. They’re known for their shy and reclusive nature, staying out of sight and rarely venturing from their webs.

Natural Predators: Despite their venomous defense, Western Black Widows have several natural predators, including birds, wasps, flies, and other spider species. These predators help maintain the ecological balance by keeping the spider population in check.

Prey-Predator Dynamics: The Western Black Widow’s role in the food web as a predator of insects and as prey for other species is a fundamental aspect of their ecological significance. They contribute to the biodiversity and health of their habitats through these dynamic interactions.

Relationship with Humans: While their venom is potent, Western Black Widows are generally not aggressive towards humans and will bite only if threatened. Their presence in undisturbed, dark areas of human dwellings is often due to the availability of prey rather than a preference for cohabitation. 

Female Western Black Widow

Quick Facts

Other namesWestern widow
Lifespan1 to 2 years
DistributionWestern belt of North America, southern Great Plains, Mexico, and southwestern Canada (British Colombia to Manitoba)
HabitatWhen outdoors they are known to be terrestrial; if living indoors, they are said to thrive in dwellings of humans which are dark, dingy, and not frequently accessed
Common predatorsBirds, wasps, flies as well and other spider species
DietMostly insects that get trapped in their web
Western Black Widow Spider

Did You Know

  • When the male succeeds in finding a female for mating, he often drums the web of his partner using his abdomen to seek her approval.
  • The species of widow spiders are reputed for killing their mates, but the Western black widow is an exception in this regard.
  • Research conducted at the San Diego State University and Northwestern University has shown that silk produced by them is so strong that it may be used in making textiles for athletes and the military.

In conclusion, the Western Black Widow spider is an important organism within its ecosystem, performing essential pest control functions.

Western Widow

Have you ever heard about the Western Black Widow spider? It’s a special spider found mostly in the western areas of North America. They are closely related to the northern black widow. Stick around, and we’ll share some fun facts about this interesting creature!

Western Black Widow

Physical Description and Identification

Adults

  • Size: Females are 0.5 inches (15 mm) in length with a leg span between 1.5 and 2 inches (38.1 to 50.8 mm). Males are however smaller about 1/3rd the size of their female counterparts.
  • Color: They have a glossy black body(mostly the females)with red hourglass markings on the undersides of their abdomen, which can also be yellow or even white (which is rare though). The male spiders are not completely black but have shades of gray or light brown on their body. The hourglass pattern is present in the males too, though it is more orange than red and at times even yellow.
  • Other characteristics: The bottom half of the hourglass pattern is slimmer, while the top part is wide.
Western Black Widow Spider Size

Eggs

The eggs attached to the mother’s web are pear-shaped with their color being whitish-yellow or pear-shaped. In a particular sac, there are about 200 eggs that hatch within two weeks of being laid.

Western Black Widow Egg Sac

Spiderlings

Both the males and females have the same color, with the topside being gray or olive, striped in yellow or white. In the undersides of the spiderling’s abdomen, an hourglass pattern or two triangles facing opposite to each other may be seen.

The Web

The web resembles a cobweb made of strong, white silk, found under logs, rocks, big crevices, or cracks.

Western Black Widow Web

Are Western Black Widow Spiders Venomous?

Yes, Western Black Widow Spiders are venomous. Their venom is strong and helps them catch food.

Can Western Black Widow Spiders Bite?

Yes, Western Black Widow Spiders can bite. They might bite if they feel threatened. Their bite might result in sharp pain just like the pricking of a pin, while some can experience mild symptoms like swelling or redness.

Male Western Black Widow

Ecological Importance and Behavior of Western Black Widow Spider

These spiders are vital for controlling insect populations, preventing outbreaks of pest species. They exhibit unique behaviors, such as the males’ abdominal ‘drumming’ on females’ webs as a mating ritual. They’re known for their shy and reclusive nature, staying out of sight and rarely venturing from their webs.

Natural Predators: Despite their venomous defense, Western Black Widows have several natural predators, including birds, wasps, flies, and other spider species. These predators help maintain the ecological balance by keeping the spider population in check.

Prey-Predator Dynamics: The Western Black Widow’s role in the food web as a predator of insects and as prey for other species is a fundamental aspect of their ecological significance. They contribute to the biodiversity and health of their habitats through these dynamic interactions.

Relationship with Humans: While their venom is potent, Western Black Widows are generally not aggressive towards humans and will bite only if threatened. Their presence in undisturbed, dark areas of human dwellings is often due to the availability of prey rather than a preference for cohabitation. 

Female Western Black Widow

Quick Facts

Other namesWestern widow
Lifespan1 to 2 years
DistributionWestern belt of North America, southern Great Plains, Mexico, and southwestern Canada (British Colombia to Manitoba)
HabitatWhen outdoors they are known to be terrestrial; if living indoors, they are said to thrive in dwellings of humans which are dark, dingy, and not frequently accessed
Common predatorsBirds, wasps, flies as well and other spider species
DietMostly insects that get trapped in their web
Western Black Widow Spider

Did You Know

  • When the male succeeds in finding a female for mating, he often drums the web of his partner using his abdomen to seek her approval.
  • The species of widow spiders are reputed for killing their mates, but the Western black widow is an exception in this regard.
  • Research conducted at the San Diego State University and Northwestern University has shown that silk produced by them is so strong that it may be used in making textiles for athletes and the military.

In conclusion, the Western Black Widow spider is an important organism within its ecosystem, performing essential pest control functions.

Western Widow