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If you’re one of those people who serve as a veritable mosquito buffet in the summer, it might seem like insects just bite through skin indiscriminately. However, for female sawflies, their cuts are incredibly specific. They cut into plants in very specific ways, with the insects knowing which materials to slice through, and which ones to avoid.
Scientists have now learned how they use an egg-laying organ called an oviposter to act like a saw that knows when to make a cut and when to push material to the side. The findings are detailed in a study recently published in the journal Bioinspiration & Biomimetics and could be used to create better surgical instruments that could reduce the amount of healthy tissues cut during operations. Meet the sawfly
In order to lay their eggs, female sawflies must cut into plants without killing their plant host. The plants then provide food for their developing larvae, so must be kept alive. The fly’s two-toothed blades slide against each other, but will only cut materials that are below a certain threshold. This biological sensitivity in their saw prevents damage to the plant’s vital structures, while making precise incisions for egg laying.
“We’ve discovered something remarkable–a cutting mechanism that essentially thinks for itself,” Dr. Martí Verdaguer Mallorquí, a study co-author and materials engineer at Heriot-Watt University in Scotland, said in a statement. “The sawfly’s egg-laying organ can cut through soft plant tissue but automatically avoids the plant’s tough internal ‘plumbing’ including the tubes that carry water and nutrients. This ensures the plant survives and serves as a food supply for the larvae coming from the eggs.”
According to the team, the geometry and physical composition of the tooth and how it interacts with the different materials in the plant makes this selective cutting possible.
“There are no sensors or computers but rather elegant engineering refined by millions of years of evolution,” said Verdaguer Mallorquí. Nature’s surgeons
In the new study, the team looked at two sawfly species–Rhogogaster scalaris and Hoplocampa brevis. They used electron microscopy and 3D imaging to decipher the precise geometry of their cutting teeth. Small serrations on the teeth appear to work together with larger protrusions to create this selective cutting action. They also found that different tooth designs are optimized for cutting into specific plant tissue layers.
To test its applicability to humans the team scaled up the sawfly’s cutting mechanism 400 times and tested it on fake human tissue in the lab. They saw that the cutting mechanism system operates on what’s called an ultimate stress threshold. If a material falls below this threshold, they are cut cleanly. If they are above it, they are moved out of the cutting zone without harm.
“This discovery has profound potential implications for surgical practice,” added study co-author and electrical engineer Marc Desmulliez. “Current surgical tools often struggle in complex operations. Surgeons frequently work in blood-flooded environments where visibility is poor and the risk of accidentally cutting vital structures is high.”
[ Related: This parasitic fly gives birth inside of crickets. ]
The team interviewed surgeons about the limitations of current surgical tools, and
86 percent reported that blood accumulation impairs their visibility and increases the likelihood of a mistake. Close to 80 percent expressed concerns about accidental tissue damage in surgery, while 57 percent called for better and more discriminate tool designs.
“A surgical instrument based on this natural mechanism could instinctively avoid critical tissues whilst cutting precisely where it is needed–essentially giving surgeons a tool that helps prevent mistakes,” Desmulliez added. “Further input is now needed from surgeons, but this newly discovered mechanism has tantalising prospects.”
The sawfly’s more passive cutting mechanism could become a bioinspired solution to this problem. Unlike complex robotic systems that need sensors and computational control, an approach inspired by the sawfly could be selective through pure mechanical design. According to the team, surgical saws and scalpels based on this principle could fuse the precision of scissors with the safety benefits of electrosurgical tools, without the thermal damage risks. Tip of the sawfly iceberg
The study examined only two species out of over 8,000 known sawfly species, so there is still a huge reservoir of untapped inspiration for engineering solutions. Different species have evolved distinct tooth shapes for different plant hosts, so there could be multiple surgical applications that benefit from studying sawflies.
“What’s particularly exciting is that this mechanism seems to work across multiple sawfly species, each adapted to different plant types,” said Verdaguer Mallorquí. “This suggests we could develop a range of surgical tools, each optimised for different tissue types or surgical procedures, all based on these natural cutting systems that have been perfected over millions of years.”
Scientists have now learned how they use an egg-laying organ called an oviposter to act like a saw that knows when to make a cut and when to push material to the side. The findings are detailed in a study recently published in the journal Bioinspiration & Biomimetics and could be used to create better surgical instruments that could reduce the amount of healthy tissues cut during operations. Meet the sawfly
In order to lay their eggs, female sawflies must cut into plants without killing their plant host. The plants then provide food for their developing larvae, so must be kept alive. The fly’s two-toothed blades slide against each other, but will only cut materials that are below a certain threshold. This biological sensitivity in their saw prevents damage to the plant’s vital structures, while making precise incisions for egg laying.
“We’ve discovered something remarkable–a cutting mechanism that essentially thinks for itself,” Dr. Martí Verdaguer Mallorquí, a study co-author and materials engineer at Heriot-Watt University in Scotland, said in a statement. “The sawfly’s egg-laying organ can cut through soft plant tissue but automatically avoids the plant’s tough internal ‘plumbing’ including the tubes that carry water and nutrients. This ensures the plant survives and serves as a food supply for the larvae coming from the eggs.”
According to the team, the geometry and physical composition of the tooth and how it interacts with the different materials in the plant makes this selective cutting possible.
“There are no sensors or computers but rather elegant engineering refined by millions of years of evolution,” said Verdaguer Mallorquí. Nature’s surgeons
In the new study, the team looked at two sawfly species–Rhogogaster scalaris and Hoplocampa brevis. They used electron microscopy and 3D imaging to decipher the precise geometry of their cutting teeth. Small serrations on the teeth appear to work together with larger protrusions to create this selective cutting action. They also found that different tooth designs are optimized for cutting into specific plant tissue layers.
To test its applicability to humans the team scaled up the sawfly’s cutting mechanism 400 times and tested it on fake human tissue in the lab. They saw that the cutting mechanism system operates on what’s called an ultimate stress threshold. If a material falls below this threshold, they are cut cleanly. If they are above it, they are moved out of the cutting zone without harm.
“This discovery has profound potential implications for surgical practice,” added study co-author and electrical engineer Marc Desmulliez. “Current surgical tools often struggle in complex operations. Surgeons frequently work in blood-flooded environments where visibility is poor and the risk of accidentally cutting vital structures is high.”
[ Related: This parasitic fly gives birth inside of crickets. ]
The team interviewed surgeons about the limitations of current surgical tools, and
86 percent reported that blood accumulation impairs their visibility and increases the likelihood of a mistake. Close to 80 percent expressed concerns about accidental tissue damage in surgery, while 57 percent called for better and more discriminate tool designs.
“A surgical instrument based on this natural mechanism could instinctively avoid critical tissues whilst cutting precisely where it is needed–essentially giving surgeons a tool that helps prevent mistakes,” Desmulliez added. “Further input is now needed from surgeons, but this newly discovered mechanism has tantalising prospects.”
The sawfly’s more passive cutting mechanism could become a bioinspired solution to this problem. Unlike complex robotic systems that need sensors and computational control, an approach inspired by the sawfly could be selective through pure mechanical design. According to the team, surgical saws and scalpels based on this principle could fuse the precision of scissors with the safety benefits of electrosurgical tools, without the thermal damage risks. Tip of the sawfly iceberg
The study examined only two species out of over 8,000 known sawfly species, so there is still a huge reservoir of untapped inspiration for engineering solutions. Different species have evolved distinct tooth shapes for different plant hosts, so there could be multiple surgical applications that benefit from studying sawflies.
“What’s particularly exciting is that this mechanism seems to work across multiple sawfly species, each adapted to different plant types,” said Verdaguer Mallorquí. “This suggests we could develop a range of surgical tools, each optimised for different tissue types or surgical procedures, all based on these natural cutting systems that have been perfected over millions of years.”
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