Wouldn't it be nice having organic mowing in our overgrown city.

A type of grasshopper, they generally live shy, solitary lives.
And they can continue this unremarkable existence for years.
But every now and then, desert locusts undergo a Jekyll and Hyde transformation.

When desert locusts begin to group together, a brain chemical called serotonin is released into their bodies, triggering a series of changes in their appearance and behaviour.
The insects not only change colour, becoming brighter, but also get faster, more hungry and extremely sociable.
Once in this "gregarious" phase, locusts actively seek out the company of their fellow insects, start reproducing explosively, and form groups that can develop into huge marauding swarms.

These huge swarms can contain up to 10 billion individuals and stretch over hundreds of kilometres.

Such ravenous swarms are now building up across East Africa, Yemen, Iran, Pakistan and India - and the area has been warned to be on "high alert" by the FAO.

Kenya, Ethiopia and Somalia, which have already experienced the worst swarms of locusts in decades, continue to face an "unprecedented threat", the FAO says. There is also a risk they could spread to West Africa.