Functioning ’mechanical gears’ seen in nature for the first time

Previously believed to be only man-made, a natural example of a functioning gear mechanism has been discovered in a common insect - showing that evolution developed interlocking cogs long before we did.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 intermesh, rotating like mechanical gears to synchronise the animal's legs when it launches into a jump. The finding demonstrates that gear mechanisms previously thought to be solely man-made have an evolutionary precedent. Scientists say this is the "first observation of mechanical gearing in a biological structure". Through a combination of anatomical analysis and high-speed video capture of normal  Issus  movements, scientists from the University of Cambridge have been able to reveal these functioning natural gears for the first time. The findings are reported in the latest issue of the journal  Science . The gears in the  Issus  hind-leg bear remarkable engineering resemblance to those found on every bicycle and inside every car gear-box. Each gear tooth has a rounded corner at the point it connects to the gear strip; a feature identical to man-made gears such as bike gears - essentially a shock-absorbing mechanism to stop teeth from shearing off.