Saturday, October 9, 1999 Published at 10:57 GMT 11:57 UK
Hopes for stopping locusts
Locusts: Devastate crops when they act together
By Toby Murcott of BBC Science
Scientists are one step closer to preventing one of the most devastating forces of nature - a swarm of locusts.
Researchers at Oxford University have discovered that solitary insects use a chemical to attract other locusts, sparking a swarm capable of stripping fields of crops in a matter of hours.
A big swarm of locusts can have the same appetite as a hundred thousand elephants. When locusts descend on farmland they can eat every scrap of vegetation.
Each year, swarms of locusts devastate crops in Africa and Asia leaving food shortages in their wake.
Creating a swarm
The scientists found that locusts reared in isolation normally avoid each other. But if forced into contact with others, they rapidly change their behaviour and actively congregate, starting a swarm.
Moreover, female locusts in a swarm can actually manipulate the genes in their eggs, so that emerging young want to join the others.
The scientists have extracted a variety of chemicals from the eggs of the female locusts and are close to identifying the chemical swarming signal.
Once they succeed then they hope to design other chemicals that will interfere with the process and stop swarms from starting.
They also hope to be able to use the information to produce better locust swarm predictions.