A gear system similar to those used on bicycles has been found in insects - showing that nature developed cogs long before humans.
The juvenile Issus - a plant-hopping insect found in gardens across Europe - has hind leg joints with curved cog-like strips of opposing "teeth" that inter-mesh, rotating like mechanical gears to synchronise the animal's legs when it launches into a jump, University of Cambridge researchers said.
The find demonstrates that gear mechanisms previously thought to be man-made have an evolutionary precedent.
Above: The gears in the Issus leg work in a similar way to those found on bicycles and inside car gear-boxes.
The gear teeth on the opposing hind legs lock together like those in a car gear-box, ensuring almost complete synchronicity in leg movement.
This helps with the powerful jumps the insects use to get around.
Professor Malcolm Burrows, from Cambridge's Department of Zoology, said: "This precise synchronisation would be impossible to achieve through a nervous system, as neural impulses would take far too long for the extraordinarily tight co-ordination required.
"By developing mechanical gears, the Issus can just send nerve signals to its muscles to produce roughly the same amount of force - then if one leg starts to propel the jump the gears will interlock, creating absolute synchronicity.
Co-author Gregory Sutton, now at the University of Bristol, said: "We usually think of gears as something that we see in human-designed machinery, but we've found that that is only because we didn't look hard enough.
"These gears are not designed, they are evolved - representing high speed and precision machinery evolved for synchronisation in the animal world."
Above: The gears are only found in juvenile insects and are lost as they pass into adulthood.
Suggested For You
The Morning Email helps you start your workday with everything you need to know: breaking news, entertainment and a dash of fun. Learn more