1906.] Wheeler, Founding of Colonies by Queen Ants. 103 



and instincts of the female ant can be changed or modified by such 

 a simple and definite stimulus as artificial dealation have a peculiar 

 interest. Some years ago my friend Prof. Loeb in an important pa- 

 per^ called attention to the fact that female ants (Lasius niger) are 

 negatively phototropic till the time of the nuptial flight, when they 

 become positively phototropic to a high degree, only to return to the 

 negative state after they have lost their wings. The latter state is ac- 

 companied by a positive stereotropism, which induces the insects to 

 work their way into crevices, under stones, into the soil, etc. One 

 would be inclined to regard fertilization as responsible for this change 

 from positive to negative phototropism, but mere removal of the wings 

 with tweezers not only produces the same peculiar inversion of reaction 

 towards the light, but also changes other reactions as well. Before deala- 

 tion the insects exhibit many instincts supposed to be peculiar to work- 

 ers; they eat from the manger and, like workers, may be very aggressive 

 to strange ants, though they usually pay little attention to the work- 

 ers or to the brood. After extirpation of the wings, however, they 

 become interested in the brood and solicit food from their offspring. 

 Later still they become exceedingly timid and sensitive to light, so 

 that they conceal themselves at once when the nest is opened or 

 disturbed. The physiologist would naturally seek the cause of these 

 changes in metabolic processes. Obviously the primary stimulus to 

 which the insect reacts is a privitive one, the absence of the wings; 

 but the secondary, or true stimulus must be sought within the organ- 

 ism, and since, in this case, the female ant reacts the same with an 

 empty as with a replete spermatheca, fertilization cannot be the cause 

 of the conspicuous differences in behavior before and after dealation. 

 Apparently metabolic changes in the thoracic musculature, initiated by 

 the mere absence of wings and leading to fatty degeneration of the 

 muscles and their replacement by gases, may be the secondary or 

 true stimulus. This, however, would seem to be a purely physiological 

 problem. 



To some it may appear that in the foregoing general considerations 

 I have unduly exaggerated the importance of the female ant. It must 

 be admitted that one can hardly fail to be biassed by merely con- 

 centrating one's attention on a particular object of investigation, for 

 specialization must of necessity mean limitation and undue emphasis. 

 While I do not flatter myself that I have escaped such influence in 

 the present instance, I believe I have shown that we must gain a 



• Der Heliotropismus der Thiere und seine Uebereinstimmung mit dem Heliotropistnus der 



Pflanzen. Wurzburg, 1890, p. 64 et seq. 



