How long do insects last?

May 09, 2013

Researchers from Trinity College Dublin have shown that although insects are made from one of the toughest natural materials, their legs and wings can wear out over time. The findings have been just published in the Journal of Experimental Biology.

"The single biggest cause of failure in cars, airplanes and other mechanical structures is material fatigue," said Dr. Jan-Henning Dirks, who studied the biomechanics of insects together with Eoin Parle and Professor David Taylor at Trinity's Department of Mechanical and Manufacturing Engineering. "For quite some time it has been known that this kind of fatigue behaviour easily happens in some materials, but far less in others. That's why engineers are constantly looking for ideas to design safer, more durable types of materials."

But until now nothing was known about the fatigue properties of the second-most common in the world: insect cuticle.

Insects are regarded as one of the most diverse groups of animals in the world, yet they have one thing in common: they all are made from a material called cuticle. "The insects' exoskeleton supports them in a way our bones support our body," said Dirks. "At the same time the cuticle also acts as a kind of protective skin. Cuticle is an extremely versatile . If we understood how it acts under repeated loads, we might be able to design more durable for many kinds of applications."

As a first step, the team looked at the cuticle of the desert locust. "These locusts are capable of flying across oceans and deserts, often for days or weeks at a time," said Parle, who is writing his PhD thesis about the mechanical properties of insect cuticle. "Their wings beat hundreds of thousands of times, and with their they perform thousands of jumps."

To measure the fatigue properties of the cuticle, the team took samples of the legs and wings and mechanically simulated the repeated loading that occurs in wing beats and during jumping. The researchers were able to show that both structures can withstand hundreds of thousands of cycles, with the legs being notably more resistant to fatigue. "Our results also show that due to their shape and fibrous material the legs are very well adapted to withstand the types of failure that might occur in jumping and kicking," said Parle.

"For the first time, we now actually know that insect cuticle shows after repeated loading." said Taylor. "These results are obviously just a first step. Studying insect cuticle is not only thought-provoking from the engineering point of view, where our findings might help us to develop more durable composite . Our results are also interesting from the biological perspective, where we can learn more about how insects evolved to become one of the most successful groups of animals."

Explore further: Rising temperatures can be hard on dogs

More information: Dirks, J., Parle, E. and, Taylor, D. Fatigue of insect cuticle, The Journal of Experimental Biology (10) 2013.

add to favorites email to friend print save as pdf

Related Stories

Researchers establish how super strong insect legs are

May 18, 2012

(Phys.org) -- Researchers from Trinity College Dublin have shown that insects are made from one of the toughest natural materials in the world. The study’s findings have been recently published in the ...

Why don't insect wings break?

Aug 23, 2012

Researchers from Trinity College Dublin have shown that the wings of insects are not as fragile as they might look. A study just published in the scientific journal PLOS ONE now shows that the characteristic networ ...

From protein to planes and pigskin

Sep 21, 2011

Scientists may soon be able to make pest insects buzz off for good or even turn them into models for new technologies, all thanks to a tiny finding with enormous potential.

New fatigue model leads to more durable ships

Apr 23, 2013

Heikki Remes at the Aalto University School of Engineering, Department of Applied Mechanics, has developed a model making it possible to determine how fatigue sets in with various welded steel materials. ...

Recommended for you

Rising temperatures can be hard on dogs

Jul 25, 2014

The "dog days of summer" are here, but don't let the phrase fool you. This hot time of year can be dangerous for your pup, says a Kansas State University veterinarian.

Monkeys fear big cats less, eat more, with humans around

Jul 25, 2014

Some Monkeys in South Africa have been found to regard field scientists as human shields against predators and why not if the alternative is death by leopard? The researchers found the monkeys felt far safer ...

User comments : 0