Necrobotics: Scientists create robots from dead spiders

Necrobotics: Scientists create robots from dead spiders

Scientists in the USA have made a breakthrough: They have developed a robot from a dead spider. With their work they want to have established a new field of research, “necrobotics”.

Animals have always been role models for robotics, which studies their evolutionary morphology and the mechanics of their movement and transfers the findings to mechanical constructions. Now scientists in the USA have gone a step further than “just” imitating organic nature with inorganic materials. They have created a construction in which a dead animal body is a component in a technical system. Specifically, they developed a powerful mechanical gripping machine from a spider carcass.

The scientists at Rice University in Houston, Texas, describe the results of their study, which they published on the Wiley Online Library website, as “necrobotic grippers”. In the construction, nature is a role model and at the same time an integral part. Spiders are therefore particularly well suited for a mechanical gripper, the researchers believe, as they have a “unique movement mechanism”. Unlike mammals, which move by tensing and relaxing opposing muscles, spiders do so using hydraulics.

Move and grip by hydraulics

The movement of the spider’s legs is generated by pumping blood in and out of the animal’s forebody, to which its eyes and mouthparts are attached in addition to its eight legs. When the abdomen – the technical term is prosoma – contracts, the blood flows into the flexor muscles of the legs, which in turn stretch due to the resulting hydraulic pressure. If the abdomen expands, the blood flows out of the flexor muscle and the legs contract.

The scientists working with engineer Daniel J. Preston made use of this mechanism. Their “necrobotic grasper” was a dead wolf spider, into whose abdomen they inserted a needle. They then pumped air into the animal through this needle sealed with glue. This stretched his legs. If they removed the air again, the legs drew in. This in turn allowed them to grab an object like the legs of a living spider.

Powerful robotic spider

Similar to a living spider, the “necrobotic gripper” succeeds particularly efficiently. According to the researchers, the construction can grip objects that are both “sensitive” and “irregular” in shape and of “a greater mass”. As for the latter, they give a specific number. The spider could therefore lift 130 times its own weight. Another advantage of the mechanism: it can maintain the performance for a long time. It is only after 1,000 cycles that the strength of the spider legs would have started to weaken, it is said.

With their work, Preston and colleagues want to have taken the “first step” in a new field of research, which they call “necrobotics”. Hence the name of their mechanism’. The term is a portmanteau of the words “necro” – that’s Greek and means “dead body” or “corpse” – and “robotics”. The scientists are confident that their work will continue to bear fruit. In further studies, the “independent operation of the individual spider legs” could be explored. But the “biotic material” of other creatures “with similar hydraulic properties” could also become the subject of “necrobotics”.