Page:Popular Science Monthly Volume 68.djvu/301

Rh Although the foregoing facts belong to ethology rather than to comparative psychology, it seemed necessary to review them before emphasizing their bearing on certain general questions. The behavior of the queen ant may be said to depend, first, on a relatively fixed inherited predisposition, or instinct; second, on inherited plasticity or adaptability; third, on constantly changing physiological states, and fourth, on stimuli which are partly primary and external and partly secondary, internal or true stimuli. These last are probably identical, as suggested by Jennings and others, with the physiological states, which in turn are evidently to be conceived as metabolic processes. That the queen ant profits by her prenuptial sojourn in the parental nest to learn by experience, tradition and imitation, I have no doubt, but queens hatched in isolation show that this acquisition is insignificant in comparison with the inherited instincts. These appear as elaborate catenary reflexes, of which the reactions to light and contact stimuli may be taken as examples. In her callow stages the queen is negatively phototropic and positively stereotropic, but as the time for her nuptial flight approaches, these reactions are reversed, so that she seeks the light and avoids contact with the walls of the nest. After fertilization she again returns to the prenuptial condition—she shuns the light and tries to bury herself in the soil or under stones. These reactions, first described by Loeb, are as irresistible as they are adaptive. It can be shown, moreover, that these changes in tropisms are accompanied by changes in other instincts. My attention was first directed to the stereotyped character of these reactions in the queen ant by a simple experiment. I found that merely pulling off the wings with the tweezers caused the insect to pass at once from positive phototropism and negative stereotropism to the reverse. This shows that the change is not caused by fecundation, since artificially dealated virgin queens went through the complex catenary reflex of founding a colony with the same precision as fertilized individuals.

These and other observations, which I am unable to give in the space at my disposal, all point to constantly changing metabolic states as the mainspring of the queen ant's behavior. She is, in fact, a veritable chemical laboratory, in which we can see more clearly than in many other animals, a direct relation between behavior and the flux of metabolism.

I hasten over this matter to another general problem. The discovery that the queen ant really possesses, at least in potentiâ, all the instincts of the worker, besides others peculiar to herself, puts a different construction on a matter which has long been puzzling theoretical zoologists. It has been taken for granted that worker ants are necessarily sterile and that they possess morphological, physiological and psychological characters not represented in the queens of their