People who are terrified of spiders shouldn’t be particularly happy about this development. However, the scientists who have turned them into mechanical tweezers believe they could have tangible benefits. The invention has been baptized with the name of ” necrorobot” .
It all started when Faye Yap, one of the researchers and a mechanical engineering student, saw a dead spider curled up in the hallway and wondered if she could use it as a robot part. The paws of these animals can grasp large, delicate, and irregularly shaped objects firmly and smoothly without tearing them to pieces .
Yap and a team of researchers from Rice University set to work to do just that, make the legs of a dead wolf spider ( Lycosa tarantula ) unfurl and grab objects. This new type of robotics has been called “necrobotics”.
The legs of spiders do not have muscles to extend, but the movement is done by hydraulic pressure . The prosomatic chamber contracts and sends internal body fluid to the legs. In this way they spread.
The scientists inserted a needle with a sealed tip into the spider’s prosome chamber. A small puff of air through the syringe was enough to activate the spider’s legs, achieving a full range of motion in less than a second.
“We took the spider and put the needle in it without knowing what was going to happen,” Yap says in a video posted on the Rice University website. “We had an estimate of where we wanted to put the needle. And when we did it, it worked, first time, first time. I don’t even know how to describe it, that moment.”
The scientists got the dead arthropod to grab onto a small ball and used that experiment to determine a maximum gripping force of 0.35 millinewtons. He was also able to pick up delicate objects and electronics, even removing a jumper wire attached to an electrical plate and moving a block of polyurethane foam. They also showed that the spider could support the weight of another spider of the same size.
When a spider dies, the hydraulic system that allows it to extend its legs stops working. The flexor muscles go into rigor mortis, but since these only work in one direction, the spider coils.
As the researchers point out in their article published in Advanced Science , most robotic components are quite complicated to manufacture. Spiders are also complex and abound. “The necrobotics concept proposed in this work takes advantage of the unique designs created by nature that can be complicated or even impossible to reproduce artificially ,” say the researchers.
Furthermore, spiders are biodegradable , so their use as robotic parts would reduce the amount of waste generated in the robotics industry. “One of the applications we could see this for is micromanipulation, and that could include things like microelectronic devices,” Preston says in the video.
One of the drawbacks of the dead spider clamp is that it begins to experience some wear after two days or after 1,000 opening and closing cycles . “We think that’s related to joint dehydration issues. We think we can overcome that by applying polymer coatings,” explains Preston.
The researchers experimented with covering wolf spiders in beeswax. They found that its mass decline was 17 times less than that of the uncoated spider over 10 days, meaning it held more water and its hydraulics could work longer.
Referencia: Yap, F., Preston, D. et. al. 2022. Necrobotics: Biotic Materials as Ready-to-Use Actuators. Science Advanced. DOI: 10.1002/advs.202201174
