Mechanical gears: insects got there first

When it comes to engineering, humans are an innovative bunch.

 

But sometimes, it turns out that the natural world got there first. Scientists have discovered that a certain type of plant-hopping insect boasts mechanical gears that are astonishingly similar to those in our bikes and car gearboxes.

Scanning electron micrograph image of the tiny insect gears (image credit: Malcolm Burrows)

 

 

Researchers in the UK made the discovery after filming high-speed videos of the Issus coleoptratus nymph as it jumped. They noticed that the young insects sported curved strips of gear teeth on their hind legs.

 

Before leaping forward, the baby planthoppers lock together these tiny gears. The researchers say that this ensures both legs move simultaneously - within a fraction of a second of each other - propelling the insect powerfully from leaf to leaf.

 

"We usually think of gears as something that we see in human-designed machinery," said Gregory Sutton at the University of Bristol, "but we've found that this is only because we didn't look hard enough."

The baby plant-hopping Issus coleoptratus (image credit: Malcolm Burrows)

 

 

Interestingly, the gears are only found in the nymph stage of the insect – they disappear when the insect undergoes its final moult to become an adult. It’s not known why they vanish, but it may be because any damage to the gear teeth during adulthood would reduce the mechanism's effectiveness.

 

These incredible gears are the very first example of a functional cog mechanism in nature – proof that evolution is perhaps the best engineer of all.

Source: Science Focus