"The American biologist Paul Ehrlich likened the loss of species from an ecological community to randomly popping out rivets from the wing of an aeroplane. Remove one or two and the plane will probably be fine. Remove ten, or twenty, or fifty, and at some point there will be a catastrophic failure and the plane will fall from the sky. Insects are the rivets that keep ecosystems functioning...In Paul Ehrlich's analogy we may be close to the point where the wings fall off."