0 comments on “Design, Naturally: Wasps take the sting out of brain surgery”

Design, Naturally: Wasps take the sting out of brain surgery

By Anwen Bowers

“I cannot persuade myself that a beneficent & omnipotent God would have designedly created the Ichneumonidæ with the express intention of their feeding within the living bodies of caterpillars …”

This statement from Darwin is often quoted in discussions about his changing relationship with religion as he developed his theory of evolution. 150 years later, the ichneumonidae in question are taking a step towards shedding their demonic reputation by inspiring a new approach to neurosurgery.

| Image: Sean McCann
Pretty deadly. We could look at ichneumonidae ALL DAY.| Image: Sean McCann

The ichneumonidae are a subfamily in possibly the largest group of animals in the world – the parasitoid wasps. Estimates of the total number of ichneumonidae species alone reach up to 100,000 – more than all the vertebrate species in the world. The wasps gain their name because they brutally kill their host species, as opposed to parasites which drain the resources of an organism without causing significant harm. Indeed, life histories of the parasitoid wasps are close to the stuff of nightmares.

The extremely high diversity of ichneumonidae has arisen because each species of wasp has evolved to target just a single type of prey, and to do it as efficiently as possible. Each species is distinguished by its specialised weaponry or tactics that allow them to tackle their prey in their niche habitat or lifestyle. For example, Lasiochalcidia igiliensis’ chosen host is the antlion larva, a ferocious predator in its own right with vicious jaws that it uses against a range of arthropod prey, even spiders.

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A badass Antlion larva clearly has only one thing to fear. Fear of L. igiliensis itself. | Image: Larah McElroy

The seemingly fearless L. igiliensis has been observed to bait the antlion larva, encouraging it to attack the wasps itself. At the point of attack, the wasp will use its powerful legs to prise the jaws of the antlion open, whilst simultaneously depositing an egg into the antlion larvae’s throat. There the egg will incubate, feeding on the antlion from the inside, until the time for metamorphosis comes. At this point the wasp will burst out from the antlion, not unlike the infamous scene from Alien.

Strategies in other species include a fibrous mesh that traps air allowing the wasps to dive down and reach caddis fly in their underwater habitat, and a hormone invisibility cloak that allows the wasps to live within an ants nest, even up to adulthood, without detection. These guys are the Q Branch of the insect world.

M. macrurus prepares to drill. | Image: Evan Kean
M. macrurus prepares to drill. Just look at that ovipositor. Stunning, and inspiring… | Image: Evan Kean

Here at Rising Ape we can vouch from experience that great ideas happen when you put a bunch of scientists from different backgrounds in a room, and maybe give them a bottle of wine. This seems to be what happened in the case of Dr Ferdinando Rodriguez y Baena, a medical engineer who found himself inspired by a serendipitous dinner party conversation with zoologist and biomimetics expert Julian Vincent.

Vincent described how the parasitoid wasp species Megarhyssa macrurus, is able to use her egg laying tube to drill down into tree bark, where she deposits her eggs onto the larvae of the pidgeon tremaz horntail (how did this come up as a topic?! Over dessert?). This is possible thanks to a complex structure of three tubes that can bend and flex as the wasp drills, allowing her to position her eggs with pinpoint precision.

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The three parts of this needle echo the ovipositor of the drilling wasp and give it unparalleled flexibility. | Image: UCL

This elegantly specialised structure gave Baena the idea for a new style of needle that mimics the ovipositor. The design allows surgeons to control and manoeuvre the needle inside the patient, navigating around sensitive and fragile parts of the brain. This minimally invasive surgical procedure could even allow surgeons to deliver drugs to very specific areas in the brain, potentially treating diseases such as brain tumours and Parkinson’s. By saving lives for a change, the ingenious ichneumonidae wasps could be about to improve their reputation.  Who knows, even Darwin may have approved.

0 comments on “Design, Naturally: Sharkskin V Superbugs”

Design, Naturally: Sharkskin V Superbugs

By Anwen Bowers

Antimicrobial resistance is one of the biggest challenges faced by the healthcare industry. The evolution of superbugs such as MRSA is evidence that the arms race between antibiotics and bacteria is not a sustainable strategy for preventing infection and keeping patients healthy. Bacteria are able to make infinite changes to their DNA, but there isn’t an infinite supply of new drugs available to target them. Scientists looking for alternative methods to tackle the spread of disease causing bacteria have turned to the natural world for inspiration.

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Opens doors, spreads diseases, can be opened by velociraptors. | Image: Public domain

Bacteria in hospitals spread through contact. If a person touches a surface that hosts bacteria, they can pass it along next time they touch a piece of equipment, or a patient. So could making surfaces inherently resistant to bacteria be an effective way of stopping the transfer and spreading of disease?

Traditional approaches to keeping surfaces sterile involve using some sort chemical agent, for example treating socks with silver to keep smelly feet at bay (equally effective against vampires). The disadvantage of chemical treatment is that protection is short lived, and needs constant renewal. Research suggests that silver nanoparticles in socks last not much longer than a few washes, as the silver is rinsed out into the environment where it becomes a poisonous threat to wildlife.

In a paradigm shift in strategy, scientists have proposed a new mechanical approach to keeping surfaces clean. Taking inspiration from the sea, they want to develop a texture that prevents bacteria from spreading by discouraging microbes from settling in the first place.

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Hull is filthy. The boat’s hull that is. | Image: Glenn Batuyong

Place almost anything underwater and it won’t be long before a thin film of green slimy phytoplankton will start to settle. This plankton is the trigger for a chain reaction of settlement, as larvae of adhesive animals such as anemones and barnacles will soon follow. This has long been a problem for the shipping industry as fouling like this on ship’s hulls creates a huge amount of drag, slowing down the vessel and adding fuel costs. Even whales, despite their constant movement, will succumb to the nuisance of barnacles and parasites.

But scientists observed that sharks remain clean and crust free, even into old age. For a long time it was thought that sharks move too quickly through the water to give anything any time to settle. Closer inspection of the surface of their skin provided an alternative answer. Sharks are covered in specialised scales called dermal dentacles.

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Sharks: Creating the worst place for bacteria to hang out for 100 million years | Image: Pascal Deynat/Odontobase

Dentacle means “small tooth”, a name derived the dentine tissue from which they’re made and the same found in your teeth. Dermal dentacles are highly textured, and when meshed together they form an extremely complex surface, full of micro mountains and canyons. This surface appears to be too unstable for any bacteria to settle and establish a community effectively.

Without the base layer of microscopic organisms, the bigger problem of larger, fouler organisms cannot develop, and the shark remains clean and smooth. This evolutionary advantage then helps the seas’ top predators move swiftly through the water in pursuit of their prey.

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‘Phelps who? Bet I’m cleaner and faster.’ | Image: Mark Conlin

Shark skin is already well studied, and has inspired a range of products, famously the Olympic grade swimwear that can reduce drag and shave milliseconds of a swimmer’s time. To use it as a surface for hospitals was the idea of Anthony Brennan, founder of the company Sharklettm , who have trademarked a textured pattern based on the structure of sharkskin. The company claims that Sharklettm surfaces harbour 94% less bacteria than standard worktops and equipment.

Installed in places such as drawer handles and even surgical equipment, Sharklettm could be a cost effective way of reducing the spread of bacteria, as well as use of antiseptic and not to mention the time staff spend cleaning surfaces. What has evolved over millions of years could be a solution to a very pressing 21st century issue.