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Smooth as silk: Scientists reveal Australian ant-killing spider hunting secrets | Spiders

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Mid-air cartwheels, judicious use of sticky silk, and rapid rappelling down trees are all done in the blink of an eye. Researchers have identified how an Australian ant-killing spider captures prey twice her size.

Acrobatic behavior of Australian ant-killing spiders, Euryopis umbilicatawas first recorded by scientists as it hunts and eats striped sugar ants.

During the day, ant killers hide under the bark of eucalyptus trees. At night, they perch on tree trunks and wait for the approach of unsuspecting ants. Small spiders have a size of up to 6 mm, and their prey is about twice as large.

Lead author of the study, Professor Mariella Herberstein of Macquarie University, said: .

“Then, while catching the ant, it circles and moves away from the ant. At that stage, [the prey’s] Fate is sealed. ”

All steps of the spider’s attack sequence occur within 1 second. Herberstein describes it as an “incredible” feat.

She likened Ant Killer to a climber rappelling down a rope. There is an ant-killer spider at the end of the rope.”

Once the sugar ant is anchored, the spider runs silk around the ant.

“When the ant gets stuck enough, she nibbles on the ant’s leg and the venom does its job,” Herberstein said.

After analyzing 60 hunts, we found that ant kills were successful in 85% of prey encounters. The only time the spider failed was when the ant fell off the tree trunk before the ant killer could tag it with silk.

Ant-killers belong to the family of spiders, Theridiidae, and are adapted to feed on six-legged insects. Many other species in this family, including the redback spider, also have sticky silks, but rely on webs to catch prey rather than direct contact.

The first to observe this behavior was Alfonso Aceves-Aparicio, a PhD student at Macquarie University and the University of Hamburg. He noticed little spiders sitting on tree trunks, waiting for ants.

Australian ant killers are found in the eastern states of the country, Queensland, New South Wales and Victoria.

More than 99% of the ant-kill prey was ants, and 90% of the diet consisted specifically of striped sugar cane ants. “We think of spiders as predators…but they’re generalists, which means they eat anything, more or less,” said Herberstein.

There are other spiders with specific appetites. For example, Bolas-her spiders only eat male moths and mimic the pheromones of female moths to attract prey.

More than 50,000 species of spiders have been described in the world so far, but only one species is known to be vegetarian. Bagheera KiplingiCentral American jumping spider.

The research was published in the Proceedings of the National Academy of Sciences.