Surgical Lessons from Sawflies

Most of us detest insects. Despite years of being told they are more afraid of me than I am of them, I still flinch and bolt when I see them, hoping someone else is brave enough to handle them. It is practically muscle memory at this point. However, for many of us, this inbuilt fear of insects makes it easy to overlook their immense value, especially in advancing cutting-edge surgical innovation. Medical technology is progressing rapidly, and sawflies are the new contenders inspiring these developments.

Sawflies are wasp-like insects found across the Northern Hemisphere, typically residing in woodland and forest habitats. Breakthrough research at Heriot-Watt University in Edinburgh discovered how female sawflies make ultraprecise cuts on their plant hosts when laying their eggs. Sawflies must cut into plants to lay their eggs without damaging the plant host, as it supplies vital water and nutrient stores to the larvae. The egg-laying organ, the ovipositor, interacts with the internal structure of the plant, knowing when to cut and when to preserve the tougher tissue. This practice, refined by millions of years of evolution, means sawflies can naturally construct safe breeding grounds to lay their eggs entirely through biological instinct. Scientists are hoping that this technique, if replicated, can strengthen the accuracy of surgical instruments used to operate on human beings.

“We have discovered something remarkable — a cutting mechanism that essentially thinks for itself.” This statement is by Dr Martí Verdaguer Mallorquí, lead scientist at Heriot-Watt University in partnership with scientific experts from the Senckenberg German Entomological Institute in Müncheberg and National Museums Scotland. The team utilised both 3D imaging and advanced electron microscopy to break down the internal architecture of the sawfly’s teeth-cutting mechanisms. They identified that particular tooth patterns are optimised to cut specific layers of the plant’s tissue, creating a highly sophisticated and efficient egg deposition process. Following this, the research team scaled up the sawfly cutting technique and tested it on a laboratory surface that replicates internal human tissue structures. They discovered that the system relies on a pressure limit; below a certain limit, tissue materials are cut, but above it, they are moved aside, creating a selective cutting technique.

So how exactly can this sawfly discovery improve modern surgical practices? When the Herriot-Watt scientists spoke with surgeons, nearly 80%voiced concern about accidentally harming healthy tissues whilst operating. Surgeons often operate in blood-heavy, high-stress settings with limited visibility, increasing the likelihood of surgical error. If scientists can replicate the sawfly’s cutting technique with modern surgical tools, like scalpels, it can enhance accuracy and reduce fatal risks in the operating room. The Heriot-Watt team has already developed a large-scale analytical model that breaks down the steps of how the cutting works. The next step requires collaboration with surgical tool manufacturers to develop prototypes based on the insect’s technique to design and test these innovative, lifesaving instruments.

‘‘Nature’s engineering, honed over millions of years, still has much to teach us,’’ said Dr Vladimir Blagoderov, curator of invertebrates at National Museums Scotland. This scientific field is called Biomimetics, a practice that uses nature and natural systems to develop technologies that address complex human problems. This research highlights biomimetics' potential to revolutionise modern medical technology through understanding and applying natural biological solutions. So next time an insect shows up uninvited, think twice — it could be holding the blueprint for the next big breakthrough for the future of surgery.

Image from Wikimedia Commons