For one tiny Australian spider, somersaulting is the key to taking over ants twice its measurement.
Ants — armed with highly effective jaws and typically chemical weapons — are so harmful to spiders that fewer than 1 p.c of arachnids try and hunt the bugs (SN: 9/8/21). High-speed footage now reveals that the Australian ant-slayer spider (Euryopis umbilicata) can deal with this dangerous prey by leaping over and lassoing its victims with silk.
The looking maneuver hasn’t been present in another spider species, researchers report September 19 within the Proceedings of the National Academy of Sciences.
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“This acrobatic behavior is just fascinating. I’ve personally never seen this kind of hunting,” says Paula Cushing, an evolutionary biologist and curator of invertebrate zoology on the Denver Museum of Nature & Science, who was not concerned within the examine.
Alfonso Aceves-Aparicio, a behavioral ecologist on the Max Plank Institute for Chemical Ecology in Jena, Germany, stumbled throughout the somersaulting spiders whereas strolling residence one night time. A graduate pupil at Macquarie University in Sydney on the time, Aceves-Aparicio was intrigued when he seen darkish dots darting throughout the pale bark of a eucalyptus tree.
The dots had been tiny spiders shifting amongst ants. Suddenly, one of many spiders jumped. “I thought it was trying to escape an ant,” Aceves-Aparicio remembers. “But then I saw the ant floating and I thought, woah, there’s something going on here.”
Aceves-Aparicio borrowed a high-speed digicam to see what the spiders had been doing in higher element. By slowing the motion down, he and his colleagues may see that the spiders had been in reality looking ants in a very unknown manner.
Most ant-hunting spiders use webs or sneak up on their prey from behind to attenuate threat. But regardless of being smaller than their prey, Aceves-Aparicio’s spiders had been dealing with banded sugar ants (Camponotus consobrinus) head on. Each spider positioned itself in order that it may watch ants as they moved up the tree. As one approached, the spider flipped above its prey. Once within the air, the spider latched a thread of silk onto the ant.
Ant-slayer spiders seize their prey by leaping over ants and tagging them with a thread of silk (proven right here in actual time, then sluggish movement) — a leap that lasts all of some milliseconds. The spiders then dart round ants to lure them in additional silk and sweep them off their ft.
This single tethering motion — carried out within the area of milliseconds — decided whether or not the hunt would succeed. If the tether caught, the spider then darted across the ant, deftly encircling them with extra silk and yanking them off their ft to be dragged off and consumed.
What stands out to Aceves-Aparicio and his colleagues was the approach’s effectiveness. Predators like lions and wolves are inclined to miss round 50 p.c of their meant targets. The success fee of the 60 spider hunts that the researchers filmed was a staggering 85 p.c.
To Aceves-Aparicio, the invention reveals that extraordinary behaviors can disguise in plain sight. “The message here is to have a little curiosity and to pay attention,” he says. “There are things going on everywhere. We just have to be there to find them.”