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Redback (Latrodectus hasseltii)

Redback spider, alternately known as the Australian black widow, originated in the Southern or Western parts of Australia. Though, at present, it is found throughout Australia and even in New Zealand. It is considered one of the most venomous spiders, with its bites resulting in severe consequences, including fatality.

Redback Spider

Physical Description and Identification

Adults

Size: Female redback spiders are around 0.39 inches (0.99 cm), and males are smaller, measuring 0.11-0.15 inches (0.27-0.38 cm).

Scientific Classification

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 and an hourglass-like pattern on the undersides.

Other Characteristic Features: The spiders have eight eyes and small fangs. Their chelicerae have venom glands attached to them.

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 eight 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 in their mother’s web for a while and then start building their 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 prey 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 into humans than females. The venom has enzymes, toxins, alpha-latrotoxin, and neurotoxin. Bite from the spider is extremely painful, and it needs medical supervision immediately, lest it could be fatal. To treat such conditions, there is a certain antivenom. Symptoms of a redback spider’s bite are vomiting, nausea, and sweating.

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, which they applied on the tip of their spears.
  • The species has influenced the famous Australian band, The Angels, so much so, that their 1991 album Red Back Fever was named after them.
  • 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 a “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

Redback spider, alternately known as the Australian black widow, originated in the Southern or Western parts of Australia. Though, at present, it is found throughout Australia and even in New Zealand. It is considered one of the most venomous spiders, with its bites resulting in severe consequences, including fatality.

Redback Spider

Physical Description and Identification

Adults

Size: Female redback spiders are around 0.39 inches (0.99 cm), and males are smaller, measuring 0.11-0.15 inches (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 and an hourglass-like pattern on the undersides.

Other Characteristic Features: The spiders have eight eyes and small fangs. Their chelicerae have venom glands attached to them.

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 eight 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 in their mother’s web for a while and then start building their 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 prey 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 into humans than females. The venom has enzymes, toxins, alpha-latrotoxin, and neurotoxin. Bite from the spider is extremely painful, and it needs medical supervision immediately, lest it could be fatal. To treat such conditions, there is a certain antivenom. Symptoms of a redback spider’s bite are vomiting, nausea, and sweating.

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, which they applied on the tip of their spears.
  • The species has influenced the famous Australian band, The Angels, so much so, that their 1991 album Red Back Fever was named after them.
  • 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 a “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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