Page:Popular Science Monthly Volume 68.djvu/299

Rh supply of food-tissue in the first place. Only the very best endowed individuals live to preserve the species from extinction. I know of no better example of natural selection through the survival of the fittest.

It is certain that the colonies of most species are founded in the manner here described. It is certain, moreover, that all this is rendered possible by the nutritive endowment of the queen. As the winged germ of the species she has all the advantages that a yolk-laden has over a comparatively yolkless egg. Now among the 5,000 known species of ants we should expect to find considerable differences in the quantity of nutriment stored up in the young queen. And this is unquestionably the case. In some species the queens are of enormous size, in others they are very small compared with the workers. And since queens of

 Atta sexdens There are about 100 eggs which the queen has placed in a depression in the middle of the garden. Near the periphery there are three drops of the fecal liquid with which the queen manures the garden. (Alter J. Huber.)

average dimensions are able to start colonies by themselves alone, we should expect that unusually large queens would be able to accomplish even more, and very small queens less. This, too, is borne out by observation.

Unusually large queens are found in the genus Atta, a group of American ants that raise fungi for food, and are, so far as known, quite unable to subsist on anything else. The female Atta on leaving the parental nest, is so well endowed with food-tissue, that she not only can raise a brood of workers without taking nourishment, but has energy to spare for the cultivation of a kitchen garden. She carries the germ of this garden from the parental nest in the form of a pellet of fungus