296 POPULAR SCIENCE MONTHLY 



hyphae stowed away in her buccal pocket, spits it out soon after comple- 

 ting her chamber, manures with her excreta the rapidly growing hyphge 

 and carefully weeds them till her firstling brood of workers hatches. 

 These then bring into the nest the pieces of leaves and the vegetable 

 detritus essential to the maintenance and growth of the garden. The 

 extraordinary habits of one of these fungus-raising ants, Atta sexdens, 

 have been recently studied in great detail by Jakob Huber, from whose 

 valuable paper I borrow a number of the accompanying illustrations 

 (Figs. 2 to 7). 



Very different is the condition of certain queen ants poorly endowed 

 with food-tissue — especially of some whose bodies are actually smaller 

 than the largest workers of their species. Such queens are quite unable 

 to bring up colonies unaided. They are therefore compelled, after 

 fertilization, to associate themselves with adult workers either of their 

 own or of a closely allied species. In the former case the queens may 

 either remain in the parental nest and omit the nuptial flight, or return 

 to the parental or to some other colony of the same species. In either 

 case they add to the reproductive energy of an already established colony 

 and thus prolong its life. If one of these poorly endowed queens, how- 

 ever, happens to alight from her nuptial journey far from any colony of 

 her own species, she is obliged to associate with alien workers. And in 

 this case, according to the species to which she belongs, one of three 

 courses is open to her. 



First, she may secure adoption in a small queenless colony of an 

 allied species. Here she is fed, lays her eggs and the resulting larvae 

 are reared by the strange workers. Eventually the alien workers die off 

 and leave the queen and her own workers as an independent and suffi- 

 ciently established colony, capable of rapid and often enormous multi- 

 plication. This is temporary social parasitism, first observed by myself 

 in some of our American ants, but since found in some of the European 

 species where I predicted its occurrence. 



Second, the poorly endowed queen may establish herself in a colony 

 of another species, but be unable, even after her workers have matured, 

 to survive the death of the host colony, except, perhaps, by migrating to 

 another nest of the same species. This is permanent social parasitism. 



Third, the queen may enter a small colony of alien workers, and, 

 when attacked, massacre them, appropriate their larvae and pupa?, care- 

 fully secrete and nurse them till they hatch and thus surround herself 

 with a colony of young and loyal workers that can bring up her brood 

 for her without any drain on her food-tissues. This is the method of 

 colony formation adopted by queens of the slave-making ants, as I have 

 found by a number of experiments during the past summer. These 

 queens thus manifest an instinct, hitherto supposed to be exclusively 

 peculiar to the workers, namely the instinct to rob the larvae and pupae 

 of another species and bring them up as auxiliaries, or slaves. 



