Garden insect is jump champion

By Jonathan Amos
BBC News Online

Move over the flea - the best jumper in the animal world is the froghopper.

To a predator, it must seem the froghopper just vanishes into thin air

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This unassuming six-millimetre-long bug which leaves "cuckoo spit" on garden foliage can spring 70 centimetres into the air.

Although the flea can do something similar, the froghopper is 60 times heavier.

"That makes froghoppers the true champions," said Professor Malcolm Burrows, head of zoology at Cambridge University, UK.

"It's not so much that they jump a little higher than fleas; it's the fact that because they're heavier, their jump performance is more impressive," he told BBC News Online.

Professor Burrows reports his investigation of insect jumping in the journal Nature.

Super acceleration

The froghopper (Philaenus spumarius) is well distributed across the world. It lives by sucking the juice out of plants.

The developing young will hide from predators inside a froth blown out of their back ends earning the insects the nickname spittlebug.

A camera operating at 2,000 frames per second can only just capture the leap

Adults leap from plant to plant. They have long been known to be good jumpers but Professor Burrows has now measured their performance.

The froghopper's secret is found in two hind legs that are so specialised to the high jump task that they are simply dragged along the ground when the insect is walking.

When the bug needs to leap, the legs form part of a very powerful catapult system. The limbs are lifted in a cocked position, held by ridges on the legs.

Two huge muscles, one controlling each leg, are contracted, and when they build up sufficient force, the legs break the lock and the insect springs forward.

"The legs snap open and all the force is applied at once," said Professor Burrows. "It accelerates in a millisecond up to a take-off velocity of four metres per second. That's phenomenal."

The scientist calculated the initial acceleration to be 4,000 metres per second per second.

Brain input

The G-force generated was more than 400 gravities in the best jumps monitored. In comparison, a human astronaut going into orbit on a rocket may experience no more than about 5 gravities.

We have always been led to believe that fleas are the jump champions of the animal world but Professor Burrows believes the record books should now be rewritten.

INSECT GOLD MEDAL Name: Philaenus spumarius Body mass: 12 milligrams Body length: 6 millimetres Froth hides young on plants

"The legitimate comparison is to look at how much force per body weight each animal can generate," he explained.

"A froghopper can exert more than 400 times its body weight; a flea can do 135 times its body weight; a grasshopper can do about eight times; and we can do about two to three times our body weight."

Professor Burrows studied the insect's athleticism as part of his research into how animals' nervous systems control body movement.

Insects are used in this type of study because their fewer brains cells are often larger than in more complex organisms, making it easier for scientists to see the processes involved.