Scientists say they may have found out why locusts gather in huge swarms, often devastating crops in Africa and Asia.
Writing in the journal Science, the researchers say the insects swarm in search of low-protein, high-carbohydrate crops from overgrazed land.
In fields treated with nitrogen fertiliser in order to produce higher-protein crops, the locusts either died or grew more slowly.
The researchers suggest that adding nitrogen fertiliser may prevent swarms.
