National Geographic : 1934 Aug
STALKING ANTS, SAVAGE AND CIVILIZED thinned out the near-by fauna, reminding us of the yearly hunts of the ancient Mon gols. Then the whole colony migrates, taking with them the larvae and the queen. Sometimes, during the heat of the day, they cluster in a hollow tree or some other depression, a huge swarm of ants, some times a bushel of them in one close mass, with brood and female in the center for protection. With them may also be found the para sites, usually beetles or wasps that super ficially resemble the ants. In watching the file one may see one of these inquilines every several minutes, or one may not notice one for an hour. The capture of a swarm, with dozens or hundreds of them at the same time, is to the collector nothing less than a gold mine. He is certain to get badly bitten and stung, as he breaks up the mass and searches for the prizes, but it is worth it. LONG LIVES THE QUEEN! The one duty of the queen is to lay eggs, and this she does almost continually, the colony increasing in number and in strength. She may have a long life, for there is one record of a queen confined in a glass observation nest who had survived for 17 years, and I once saw a 14-year-old queen who had spent her life in the col lection of a friend of mine in England. The tasks of housekeeping, nursing the babies, and gathering food are left to the worker, the undeveloped female. Contrary to general opinion, only a small percentage of workers are actually out of the nest at any one time. At home they spend much of their time in grooming themselves and each other. Most ants subsist entirely on liquid food. Even the pieces of insects which they eat are taken into the mouth cavity and the liquid pressed out and swallowed. The dry pellets are spat out. These hard pellets, by the way, sometimes are used as food by other insects which share the nest with the ants. ANTS HAVE MILLERS TO GRIND GRAIN Naturally, in a colony of many thousand individuals a large amount of food is con sumed. It has been estimated that a single nest of the large mound-building ants of Europe, practically the same as those we find throughout our Far West, collects each day insects to the number of several hundred thousand. The harvesting ants, most of them in habitants of deserts, have developed millers, with heads enormously enlarged to contain the muscles of the jaws. The ordinary worker goes out day after day and brings in seeds of plants. These the millers laboriously grind into a sort of flour, which is stored in the nest. Once in Arizona, while collecting ants, I noticed a small turret entrance to a nest. Around this were a number of mammoth ant heads. Later I found that these were the heads of the millers. The harvesting season was over. The millers had done their duty in grinding the grain; where upon the workers, provident always, had sawn their heads off. It was more eco nomical from the standpoint of the colony to raise a new brood of millers next year than to carry these over during the times of depression. From the train window the traveler in the Southwest sees large ant hills dotted over the desert. These are usually nests of the bearded agricultural ants, Pogono myrmex (see Color Plate II). They live on the seeds of grasses which they gather and store in their nests. There is usually a large area kept carefully cleared about the nest, which makes the mound stand out prominently. Sometimes surrounding these cleared areas is a fringe of the grass that supplies the food of the ants. From this, some observers have thought that the ants intentionally plant their own food. This is probably not so. Refuse from the nest is carried out and deposited at the edge of the clearing, and with this refuse may be some of the seeds which germinate there. It is thus by accident that a source of food supply appears ad jacent to the nest. These desert harvesters are fierce in the defense of their home, and it is said that small children have been stung to death while playing on the nest. I have been stung a number of times while collecting Pogonomyrmex and can testify that the sting leaves a dull pain which lasts for some time. Honey ants are another example of those that look ahead to the days of famine, piling up quantities of honeydew in living con tainers (see text, page 193, and illustra tions, pages 194 and 195).