The mortal enemies of man are not his fellows of another continent or race; they are the aspects of the physical world which limit or challenge his control, the disease germs that attack him and his domesticated plants and animals, and the insects that carry many of these germs as well as working notable direct injury. This is not the age of man, however great his superiority in size and intelligence; it is literally the age of insects. The Social Life of Animals (1938)