What is the difference between locust & grasshoppers?
Locusts and grasshoppers are identical in appearance – how they differ is in their behaviour. Locusts can exist in two different behavioural states (solitary and gregarious) whereas grasshoppers generally do not. When the population density is low, locusts behave as individuals, much like grasshoppers. However, when locust population density is high they form into gregariously behaving bands of nymphs or swarms of adults. It is this change from one behavioural state to another, known as phase change, that makes locusts such devastating pests. In addition to changes in behaviour, phase change may be accompanied by changes in body shape and colour, and in fertility, survival and migratory behaviour. These changes are so dramatic in many species that the swarming and non-swarming forms were once considered to be different species. Note, however, that the distinction between locusts and grasshoppers is not clear-cut. The migratory locust has all of the features associated with phase change