Researchers at the University of Manchester have managed to successfully train a regal jumping spider to leap at command.
It’s the first time scientists have been able to train an arachnid in such a way.
The new study, which was published in Nature Scientific Reports this week, might help unlock the secrets behind the hunting habits of these predators. It could also give engineers new information to apply to micro-robotics.
The study is the most advanced of its kind and the very first to use 3D CT scanning and high-speed cameras to record and analyse the spider’s behaviour and movements.
Other animals like dogs or pigs can be trained easily because they can be conditioned with food. But spiders typically don’t eat more than once every week, making the animal extremely difficult to incentivise.
“She would eat a cricket per week, so we couldn’t use a rewards system (to train her),” says study author Mostafa R.A. Nabawy. “And if we just gave her prey, then she would only jump motivated by the food. Then we would have to wait a week between jumps.”
The research team managed to train Kim – yeah, they called it Kim – to jump different heights and distances on a man-made platform in their laboratory. They pulled it off by manually moving her from one platform to the other until she started making the jumps on her own.
We humans can only jump one and a half times the length of our body from a stationary position. Researchers found out that Kim’s legs have the astonishing force of five times her weight at take-off, allowing her to jump more than six times the length of her own body.
“She never missed,” says Mostafa R.A. Nabawy. “She didn’t jump unless she was confident she could make the jump.”
For more than 50 years, scientists have known that spiders use internal hydraulic pressure to extend their legs, but this study confirms that hydraulic pressure is used actively to boost the spider’s muscle force in a jump.
Dr Bill Crowther, co-author of the study, elaborates, “Our results suggest that whilst Kim can move her legs hydraulically, she does not need the additional power from hydraulics to achieve her extraordinary jumping performance.
“Thus, the role of hydraulic movement in spiders remains an open question.”
Thanks to Kim, scientists are getting a better understanding of the biomechanics behind spider jumps, enabling engineers to apply the findings to other areas.
“We are familiar with robots that are aimed at taking over human functions, but there are millions of insects in the world that perform specific functions that we have interest in adapting to robotics,” says Nabawy.