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Redback (Latrodectus hasseltii)

The nocturnal spider has an Australian origin. Male redback spiders live on the web made by the female spiders and also rely on stealing food from the web. Females spiders rarely come out of their web.

Scientific Classification

Redback Spider

Physical Description and Identification

Adults

Size: Female redback spiders are around 0.39 in (0.99 cm), and males are smaller with a range of 0.11-0.15 in (0.27-0.38 cm).

Color: Females have a black abdomen with red or orange vertical stripes from top to bottom. The underside of the abdomen has red streaks, resembling a silhouette of an hourglass. The cephalothorax is black. Male spiders have a pale brown body with white markings on the abdomen. The underside of the abdomen has the hourglass figure just like the female spiders.

Other Characteristic Features: The spiders have 8 eyes and small fangs, and their chelicerae have venom glands.

Redback Spider Size

Eggs

Female spiders make a round and white egg sac and lay around 250 eggs per clutch.

Redback Spider Egg

Spiderlings

The hatching takes around 8 days, but spiderlings stay within the sac for 7-11 days more. During this time they eat the yolks and go through the molting phase. They finally come out in spring or summer. They can attack each other for cannibalism. They live on their mother’s web for a while, and then they start building their own silken thread. Afterward, they are blown away by the wind, a process known as kiting or ballooning. They have a grey body with some dark spots.

Redback Spiderling

The Web

Female spiders make webs every night in no particular pattern with strong and fine silk. The front part of the web is for retreat, both for the spider and eggs in the future. The part that is used for catching preys has sticky silk entrapment. The spiders make the web in between two layers of a surface to secure it.

Redback Spider Web

Are Redback Spiders Venomous

These spiders are venomous, and their venom comes from the holocrine venom glands. Male spiders are less capable of injecting venom to humans than female spiders. The venom has enzymes, toxins, alpha-latrotoxin, and neurotoxin. Bite from the spider is extremely painful, and it needs medical supervision immediately. To treat such conditions, there is a certain antivenom. Symptoms of redback spider’s bite are vomiting, nausea, and sweating. The venom is toxic enough to kill humans.

Even for pets, like cats and dogs, the spider bite is dangerous. The venom affects cats more than dogs.

Female Redback Spider

Quick Facts

Other Names Australian black widow
Distribution Found throughout Australia, New Zealand, countries of South Asia, Belgium, England, Iran, and the United Arab Emirates
Habitat Shrubs, tree hollows, and logs
Web Type Irregular web
Venom Fact Highly venomous
Diet Insects, trapdoor spiders, and snakes
Predator Giant daddy-long-legs spiders, cellar spiders, black house spiders and wasps like redback spider-hunting wasps, and mantid lacewings
Lifespan Females: Around 3 years
Males: Around 3 months
Male Redback Spider

Did You Know

  • The Australian aboriginal used to make a mixture of snake venom, redback spider venom, and pine tree gum. It was applied on the spear tip.
  • The species has influenced the famous Australian band, The Angels, so much so, that the band has an album Red Back Fever.
  • The South Australia cricket team’s logo is the iconic two stripes of redback spiders.
  • The ultralight trike of Australia, known as the Airborne Redback, is also influenced by the spider.
  • The Australian singer Slim Newton has a song named after the spider, “The Redback on the Toilet Seat.” The song won the “Country Music Awards of Australia” in 1973.
  • In Queensland, there is a massive sculpture of the spider at Eight Mile Plains, as one of the recognizable things of the country.
  • There is also a boot company in Australia, Redback Boots, named after the species and the image of the spider is used as its logo.
  • There was a stamp dedicated to the spider.
  • One of the species Steatoda capensis is known as “false redback spider,” due to its physical similarities with the original redback spider.
Australian Black Widow

Image Credits: Media.australianmuseum.net.au, Biomedicalsciences.unimelb.edu.au, Media.apnarm.net.au, Images.theconversation.com, Ak0.picdn.net, I.pinimg.com, Thesun.co.uk, Nnimgt-a.akamaihd.net

The nocturnal spider has an Australian origin. Male redback spiders live on the web made by the female spiders and also rely on stealing food from the web. Females spiders rarely come out of their web.

Redback Spider

Physical Description and Identification

Adults

Size: Female redback spiders are around 0.39 in (0.99 cm), and males are smaller with a range of 0.11-0.15 in (0.27-0.38 cm).

Color: Females have a black abdomen with red or orange vertical stripes from top to bottom. The underside of the abdomen has red streaks, resembling a silhouette of an hourglass. The cephalothorax is black. Male spiders have a pale brown body with white markings on the abdomen. The underside of the abdomen has the hourglass figure just like the female spiders.

Other Characteristic Features: The spiders have 8 eyes and small fangs, and their chelicerae have venom glands.

Redback Spider Size

Eggs

Female spiders make a round and white egg sac and lay around 250 eggs per clutch.

Redback Spider Egg

Spiderlings

The hatching takes around 8 days, but spiderlings stay within the sac for 7-11 days more. During this time they eat the yolks and go through the molting phase. They finally come out in spring or summer. They can attack each other for cannibalism. They live on their mother’s web for a while, and then they start building their own silken thread. Afterward, they are blown away by the wind, a process known as kiting or ballooning. They have a grey body with some dark spots.

Redback Spiderling

The Web

Female spiders make webs every night in no particular pattern with strong and fine silk. The front part of the web is for retreat, both for the spider and eggs in the future. The part that is used for catching preys has sticky silk entrapment. The spiders make the web in between two layers of a surface to secure it.

Redback Spider Web

Are Redback Spiders Venomous

These spiders are venomous, and their venom comes from the holocrine venom glands. Male spiders are less capable of injecting venom to humans than female spiders. The venom has enzymes, toxins, alpha-latrotoxin, and neurotoxin. Bite from the spider is extremely painful, and it needs medical supervision immediately. To treat such conditions, there is a certain antivenom. Symptoms of redback spider’s bite are vomiting, nausea, and sweating. The venom is toxic enough to kill humans.

Even for pets, like cats and dogs, the spider bite is dangerous. The venom affects cats more than dogs.

Female Redback Spider

Quick Facts

Other Names Australian black widow
Distribution Found throughout Australia, New Zealand, countries of South Asia, Belgium, England, Iran, and the United Arab Emirates
Habitat Shrubs, tree hollows, and logs
Web Type Irregular web
Venom Fact Highly venomous
Diet Insects, trapdoor spiders, and snakes
Predator Giant daddy-long-legs spiders, cellar spiders, black house spiders and wasps like redback spider-hunting wasps, and mantid lacewings
Lifespan Females: Around 3 years
Males: Around 3 months
Male Redback Spider

Did You Know

  • The Australian aboriginal used to make a mixture of snake venom, redback spider venom, and pine tree gum. It was applied on the spear tip.
  • The species has influenced the famous Australian band, The Angels, so much so, that the band has an album Red Back Fever.
  • The South Australia cricket team’s logo is the iconic two stripes of redback spiders.
  • The ultralight trike of Australia, known as the Airborne Redback, is also influenced by the spider.
  • The Australian singer Slim Newton has a song named after the spider, “The Redback on the Toilet Seat.” The song won the “Country Music Awards of Australia” in 1973.
  • In Queensland, there is a massive sculpture of the spider at Eight Mile Plains, as one of the recognizable things of the country.
  • There is also a boot company in Australia, Redback Boots, named after the species and the image of the spider is used as its logo.
  • There was a stamp dedicated to the spider.
  • One of the species Steatoda capensis is known as “false redback spider,” due to its physical similarities with the original redback spider.
Australian Black Widow

Image Credits: Media.australianmuseum.net.au, Biomedicalsciences.unimelb.edu.au, Media.apnarm.net.au, Images.theconversation.com, Ak0.picdn.net, I.pinimg.com, Thesun.co.uk, Nnimgt-a.akamaihd.net

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