How do locust swarms start?

One of the three types of locust that forms swarms in Africa is the Desert Locust. This locust usually lives like a grasshopper in what is called a solitary phase. Sometimes, however, all the solitary locusts from a wide a area are driven together, perhaps by the weather, and they may find the conditions just right for feeding and mating. As locusts mate and lay eggs many times in a short period, enormous numbers of young locusts hatch and become stimulated by each other to form a swarm. They change colour and when all the available plants have been eaten they migrate in search of more.