They Hop, they Jump, they Fly

Locusts on the move

When I was still living in Perth (Western Australia), the newspaper reported a case of a horse race that was being abandoned and a cricket match that was cancelled for one and the same reason: invading swarms of migratory locusts, thousands upon thousands of them. What causes these insects from time to time to build up their populations to immense numbers with hundreds of millions of individuals gathering together, migrating across the land and ravaging anything green on their way of destruction? What is known is that environmental conditions are to blame.