tionships to other insects and the vegeta- 

 tion of the planet. It is therefore par- 

 ticularly instructive to study the methods 

 whereby the ants as social insects have 

 solved the problems of nutrition, repro- 

 duction, and protection. 



The ant colony or society may be re- 

 garded as an organism which, like the 

 individual insects of which it consists, 

 grows and develops to a fixed adult size, 

 and the size to which it grows is char- 

 acteristic of the species, just as is the 

 size of any individual. Some ants al- 

 ways form diminutive colonies of only 

 a few dozen individuals, whereas the 

 colonies of other species, when mature, 

 may comprise thousands or hundreds of 

 thousands. The growth of these colonies 

 obviously depends on the quantity and 

 qtiality of the available food supply and 

 on its distribution for immediate con- 

 sumption, or its storage for the future 

 use of the colony. 



the; intricate; process oi' food 

 conse;rvation 



Ants feed on a great variety of sub- 

 stances, but in all cases only the liquid 

 portions of the food are taken into the 

 alimentary tract. If the food is solid, 

 minute particles of it are rasped off by 

 means of the tongue and pressed into a 

 small pocket in the floor of the mouth. 

 The juices expressed from the mass are 

 then sucked back through the gullet into 

 a dilated portion of the alimentary tract, 

 the crop, and the useless pellet is spit 

 out. 



The crop is very distensible, but thin- 

 walled and lined with a layer of chitin, 

 which is impenetrable to the liquid con- 

 tents, so that none of the food, so long 

 as it is stored in this receptacle, can be 

 absorbed or digested. The crop is closed 

 behind by a complicated valve, which 

 separates it from a short, bag-like stom- 

 ach, the walls of which have a permeable 

 lining, so that it and the succeeding por- 

 tions of the alimentary tract, the in- 

 testine, are able to digest and absorb any 

 food which may be permitted to enter 

 them through the valve. 



The crop and true stomach have been 

 called respectively the "social" and "in- 

 dividual" stomachs, because the liquid 

 food stored in the former is in great part 

 distributed by regurgitation to other ants, 



Photo by Mr. J. G. Hubbard and Dr. O. S. Strong: 



QUEENS OF A COMMON ANT (Camponotus' 

 am eric anus) 



One of the queens is fecundated and has 

 lost her wings and is thus prepared to start a 

 colony. Ant societies are societies of females. 

 The males really take no part in the colonial 

 activities, and. in most species, are present in. 

 the nest only for the brief period requisite to 

 insure the impregnation of the young queens. 

 The males take no part in building, provision- 

 ing, or guarding the nest, or in feeding the 

 workers or the brood. They are in every 

 sense the sexiis sequior. Hence the ants re- 

 semble certain mythical human societies like- 

 the Amazons, but, unlike these, all their activi- 

 ties center in the multiplication and care of 

 the coming generations. 



whenever they signify their hunger by 

 protruding their tongues and making sup- 

 plicatory gestures with their feelers, and 

 because none of the food in this re- 

 ceptacle can be used by the individual 

 unless it passes back through the valve 

 into the true stomach. 



The crop is thus a storage reservoir 

 from which both the individual and the 

 colony can be supplied with nutriment. 

 Other older and cruder methods of the 

 distribution and storage of food coexist 

 among ants with this more modern and 

 more efficient method. 



Thus solid foods may be carried into 

 the nest entire and then dismembered 

 and the pieces distributed to different 

 parts of the nest to be still further com- 

 minuted and sucked dry by groups of 

 ants, or the solid food may be carefully- 

 stored in special chambers. 



733 



