The Redback spider, often called the Australian black widow, comes from places in Australia. Nowadays, you can find it all over Australia and even in New Zealand. It is considered one of the most venomous spiders. Keep reading, and we’ll share amazing facts about this spider!
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.
Eggs
Female spiders make a round and white egg sac and lay around 250 eggs per clutch.
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.
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.
Are Redback Spiders Venomous?
Yes, Redback spiders are venomous. They have strong venom that can be harmful to humans. Redback spiders have venom from holocrine glands. Males are less likely to inject venom than females. The venom contains enzymes, toxins, and neurotoxins. A bite is very painful and can be fatal, requiring immediate medical attention and antivenom. Symptoms include vomiting and sweating.
Can Redback Spiders Bite?
Redback spiders can bite, especially if they’re disturbed. Their bite can be painful, and it’s important to be cautious around them. The bite is also harmful to pets, especially cats.
Ecological Importance and Behavior of Redback Spider
The Redback spider plays a vital role in controlling insect populations, contributing to the ecological balance. Females are known for their web-spinning prowess, creating intricate traps for their prey. The venom, while dangerous to humans and pets, is an essential tool for subduing prey, securing the spider’s place in the food chain.
Natural Predators and Prey-Predator Dynamics: The Redback spider’s natural predators include various species of spiders, such as giant daddy-long-legs, cellar spiders, black house spiders, as well as wasps and mantid lacewings. These predators help maintain a balanced ecosystem, keeping Redback populations in check.
Relationship with Humans: Despite their venomous nature, interactions between humans and Redback spiders that result in bites are relatively rare. With proper education, awareness, and caution, humans can coexist with these spiders, appreciating their role in the ecosystem while mitigating the risks associated with their venom.
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
Did You Know
The Australian Aboriginals 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 most recognizable things in 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.
In summary, the Redback spider, with its striking appearance, potent venom, and complex behavior, stands as a fascinating subject of study and admiration.
A female redback spider has a distinct spherical black abdomen with a prominent red or orange vertical stripe on its upper side. The underside features a red, hourglass-shaped marking. Adult females are approximately 0.39 inches in body length, making them significantly larger than their male counterparts.
A male redback spider is identified by its pale brown body, which features white markings on the upper abdomen. While it also has an hourglass-like pattern on its underside, it is typically less distinct than the female’s. Males are much smaller, measuring only about 0.11 to 0.15 inches.
Yes, redback spiders show significant size differences between sexes. An adult female’s body is around 0.39 inches (1 cm), while the much smaller male measures only 0.11-0.15 inches (3-4 mm). This makes the female substantially larger and more robust than the male, which is common in many spider species.
A female redback spider lays around 250 eggs per clutch inside a round, white, silken egg sac. She can produce several of these sacs throughout her life. The eggs typically hatch in about eight days, but the spiderlings will remain within the protective sac for another one to two weeks.
Baby redback spiders travel to new areas using a dispersal method called ballooning or kiting. After leaving their mother’s web, the spiderlings climb to a high point and release a silken thread into the air. The wind catches this thread, carrying the spiderling to a new location to establish itself.
A redback spider builds a web with no particular pattern, consisting of strong, fine silk often situated between two surfaces. The web has a retreat area for the spider and its eggs in the upper part, while the lower section contains sticky entrapment threads designed to catch crawling prey.
Yes, the redback spider is highly venomous, and its bite is considered medically significant for humans. The female spider delivers a potent neurotoxic venom through its fangs. If you suspect a redback spider bite, it is critical to seek immediate professional medical attention for proper evaluation and treatment.
Dr. James Watuwa on September 26, 2019.
Spider Team
