Stranger Than Fiction #4: How Necrobotics is Breathing Life into Robotic Innovation Using Deceased Spiders 

In the mesmerising world of robotics, nature has always served as an abundant source of inspiration. The allure of creating machines that mimic the astonishing abilities of insects, like spiders, has intrigued researchers for years. 

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The challenge, however, has been monumental – designing robots with insect-like capabilities has proven to be extraordinarily complex. But in a surprising twist, the emerging field of necrobotics presents an alternative solution, harnessing the unique attributes of deceased insects, such as spiders, to create robotic wonders that bridge the gap between the living and the mechanical.

Spiders, often lauded for their incredible mobility and efficiency, possess an intricate hydraulic or pneumatic grip system that has long captivated roboticists. This system enables living spiders to control their limbs through precise adjustments in blood pressure, operating on a limb-by-limb basis through a remarkable internal valve system. When blood pressure is increased, the limbs extend, and when reduced, antagonistic flexor muscles curl the limbs. Curiously, this mechanism explains why the legs of deceased spiders curl after death – a result of the absence of the counteracting blood pressure.

Enter necrobotics, a field that leverages the inherent capabilities of deceased spiders to craft gripping devices that embody both the marvels of nature and the innovations of technology. The process is ingenious in its simplicity: by tapping into the internal valve system of a deceased spider, researchers can inject air, inflating and extending all eight limbs. This process turns the spider's legs into micro-hydraulic grippers, a feat that seems straight out of science fiction.

In contrast to conventional bio inspired designs that focus on replicating an insect's physical form, necrobotics takes a different approach. By repurposing deceased spiders, researchers from the Preston Innovation Lab at Rice University have successfully created a pneumatically actuated gripper. This gripper showcases impressive functionality following just one uncomplicated assembly step, obviating the need for intricate and time-consuming fabrication typically associated with fluid-driven actuators and grippers.

The implications of their work are showcased in a recent paper published in Advanced Science. The deceased-spider gripper's performance is nothing short of astonishing. It exhibits the ability to lift 1.3 times its own weight and exert a gripping force of 0.35 millinewton. Even after around 700 actuations, wear is minimal. Subsequent testing revealed that after 1,000 cycles, slight cracks appeared in the spider's joints due to dehydration. However, researchers postulate that coating the spider with substances like beeswax could potentially prolong its functionality significantly. The demised-spider gripper's versatility in picking up various objects is a result of both the inherent flexibility of the legs and microscopic hairlike structures that mimic directional adhesives.

While the innovative potential of necrobotics is undeniable, it also sparks ethical contemplation. Acquiring biotic material involves the euthanization of insects, raising questions about responsible practices. In the case of the wolf spider used in this study, euthanasia was accomplished by subjecting it to freezing temperatures for 5-7 days. The lack of established guidelines for ethical sourcing and euthanasia underscores the need for a comprehensive framework that considers the ethical implications of necrobotic research.

A particularly intriguing facet of necrobotics is its exploration of the gripping forces of spiders of varying sizes. This analysis reveals that the potential gripping force of smaller jumping spiders, weighing a mere 10 milligrams, could exceed 200% of their body weight. On the other end of the spectrum, larger 200-gram goliath spiders might manage only 10% of their weight. These findings fuel curiosity about the gripping capacities of different spider species and sizes, paving the way for innovative applications and avenues for further investigation.

Looking ahead, necrobotics holds vast potential. Insects, especially spiders, offer promising possibilities due to their biodegradability and minimal ecological footprint. As technology advances, autonomous sample collection and unconventional modes of locomotion become conceivable. Exploring a diverse range of spider species can unlock new dimensions of innovation within necrobotics.

In a world where the lines between imagination and reality continue to blur, necrobotics offers a tantalising glimpse into the future of robotics. It serves as a reminder that the boundary between life and technology is becoming increasingly nuanced. The fusion of mechanical ingenuity with biological attributes invites us to reimagine what's achievable, push the boundaries of ethical considerations, and celebrate the remarkable harmony between science and the natural world.