Metamorphosis of a Desert Locust Schistocerca gregaria, showing the wings of the adult unfurling. Under conditions of overcrowding, nymphs of this species undergo a 'phase' change both in colouration and behaviour. They mass together in enormous numbers, becoming highly excited & set off in a purposeful manner devouring all vegetation that they encounter. The adults that develop from these nymphs inherit the latter's excitable behaviour. They form the familiar devastating flying swarms of locusts.