Why do locusts swarm

A.� Locusts are normally shy, solitary creatures. But in a swarm they become a destructive pest capable of stripping fields of crops in hours. Scientists claim that this dramatic transformation is caused by a biological trigger.

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The insects have touch sensitive hairs on their hind legs. When they group together the hairs are stimulated and the locusts swarm.

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Q.� Who has made this discovery

A.� A team of zoologists, lead by Professor Simpson, at the University of Oxford, UK.

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Q.� How did scientists discover this biological trigger in locusts

A.� By tickling locusts in labs with a paintbrush. When�certain parts of the locust's body was tickled. like the abdomen, the insect was unaffected. However, when a specific region of the insect's back leg was stimulated, it caused a shift from solitary to gregarious behaviour.

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Q.� Why are locusts' swarms so dreaded

A.� Swarming locusts, one of nature's most devastating forces, are legendary. Swarms with the appetite of a hundred thousand elephants are possible. Each year these insects devastate crops in Africa and Asia causing widespread famine. This is coupled with the fact that locusts apparently thrive during droughts and so strip farmlands of what little they have at the worst possible time.

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Q.� Why is it important to understand why locusts swarm

A.� The Oxford University team suggest that by pinpointing the signalling chemicals and the neural pathways along which they travel to the insects' nervous systems when the locusts change from solitary harmless creatures to swarming pests, new, more effective, control chemicals could be developed.

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Q.� How are locusts controlled at the moment

A.� The chemical DDT proved very effective in controlling the pest. However, although it was excellent at destroying the locusts it also had serious effects on the human environment.

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More recently a spray, called Green Muscle, has been proving effective in destroying locusts and grasshoppers without harming other creatures.

The spray uses a fungus, long known as a locust killer, produced on an industrial scale in an oil-based solution.

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There could be as many as 9,000,000 different species of insects worldwide; if you have a question about anyone of them, just click here to ask.