Acridids (grasshoppers and locusts) can range from being rare curiosities to abundant menaces. Some are threatened with extinction and become subjects of intensive conservation efforts, while others are devastating pests and become the objects of massive control programmes. Even within a species, there are times when the animal is so abundant that its crushed masses cause the wheels of trains to skid (the Rocky Mountain grasshopper, Melanoplus spretus Walsh in western North America in the 1860s and I 870s), while at other times the animal is alarmingly scarce (the Rocky Mountain grasshopper...

Acridids (grasshoppers and locusts) can range from being rare curiosities to abundant menaces. Some are threatened with extinction and become subjects of intensive conservation efforts, while others are devastating pests and become the objects of massive control programmes. Even within a species, there are times when the animal is so abundant that its crushed masses cause the wheels of trains to skid (the Rocky Mountain grasshopper, Melanoplus spretus Walsh in western North America in the 1860s and I 870s), while at other times the animal is alarmingly scarce (the Rocky Mountain grasshopper...