The Australian redback spider performs a fatal somersault to ensure successful mating

Nature · Published 3 October 2026 · Updated 25 October 2026 Swipe more like this →

In short: The male redback spider is a master of high-stakes courtship. To capture the female's attention and avoid being eaten, he performs a unique somersault, offering his abdomen to her mouthparts. While this risky maneuver facilitates mating, it often ends in the male's death, a sacrifice unique to this species.

The redback spider (Latrodectus hasselti) is a venomous arachnid native to Australia, where it thrives in both natural and urban environments. Often found in dry, sheltered locations like sheds, logs, and junk piles, these spiders have become increasingly common as human development provides them with ideal habitats. While they are close relatives of the famous North American black widow, DNA analysis confirms the redback is a distinct species.

The female redback is significantly larger than the male, possessing a spherical black body marked by a signature red longitudinal stripe and an hourglass-shaped spot on her underside. Her venom is a potent neurotoxin that can cause severe pain, nausea, and muscle weakness in humans. Although bites are frequent, particularly in summer, they are rarely fatal, and an effective antivenom has been available since 1956. Most bites occur when a person accidentally places a hand directly into the spider's web.

Reproduction is a complex and dangerous affair. After mating, the female can store sperm for up to two years, allowing her to produce multiple egg sacs. Each sac contains approximately 250 eggs. The male's survival strategy during mating is particularly striking; he somersaults to present his abdomen to the female, who may begin digesting him while the mating process is still underway. This behavior, which often leads to the male's death, is a rare example of sexual cannibalism within the genus.

Despite their reputation, redbacks are not aggressive. They rarely leave their webs, and their small jaws often make human bites ineffective. Their diet consists primarily of insects, though they are capable of capturing larger prey like small lizards or trapdoor spiders. Today, the redback is recognized as a unique, successful species that has adapted remarkably well to the proximity of human habitation.

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