Lippincott's Magazine of Popular Literature and Science, Vol. 22, November, 1878

by Various

EXCAVATING AN ANT-HILL.

IN the low pine barrens of Florida are large districts thickly dotted over with small mounds made by a species of ant whose habits are unknown to the scientific world. Each mound is surrounded by a circle of small chips and pieces of charcoal, which the busy inhabitants often bring from a long distance. The hills are regular in outline, with a crater-like depression on the summit, in the centre of which is the gateway or entrance.

These ants do not live in vast communities like the mound-builders of the North, but each hill seems to be a republic by itself, though separate colonies in the same neighborhood have friendly relations with each other. Their color is rufous or reddish-brown, and they are furnished with stings like bees and wasps, and, like the honey-bee, always die after inflicting a wound, for their stings are torn from their bodies and left in the victim. The pain inflicted is about the same as that caused by the sting of the honey-bee. But they are not as vicious as most stinging insects: they will submit to considerable rough treatment before resorting to this last resource.

There are three sets of neuters in each colony—major and minor workers and soldiers: also one wingless queen is found in each nest. The head is very large, especially that of the soldier.[1] The workers minor—which are the true workers—have regular well-defined teeth on the mandibles, while most of the soldiers have merely the rudiments or teeth entirely obsolete. All the queens which I have found—eighteen in number—have perfectly smooth mandibles, without the least vestige of a tooth.

Early in December, 1877, I brought a large colony of these ants from one of the hills, including the workers major and minor and soldiers, and established them in a glass jar which I placed in my study. They very soon commenced work, tunnelling the earth and erecting a formicary, as nearly as they could after the pattern of their home on the barrens. The mining was done entirely by the small workers. At first they refused all animal food, but ate greedily fruit and sugar, and all kinds of seeds which I gave them were immediately taken below, out of sight. I now visited the mounds on the barrens and found abundant indications of their food-supplies. At the base of each mound was a heap of chaff and shells of various kinds of seeds. The chaff was Aristida speciformis, which grew plentifully all about. I also found many seeds of Euphorbia and Croton, and several species of leguminous seeds. But the ants were not bringing seeds in at this time of year: they were only carrying out the discarded seeds and chaff; and only on the warmest days were they very active. But they do not wholly hibernate. Even after a frosty night, by ten o'clock in the morning many of the hills would be quite active.

SOLDIER.

I sent specimens to the Rev. Dr. McCook of Philadelphia to be named, and he identified them as Pogono myrmex crudelis, described by Smith as Atta crudelis[2] Dr. McCook predicted from their close structural resemblance to the Texan "agricultural ant" that they would prove to be harvesting-ants.

On excavating a nest I found chambers or store-rooms filled with various kinds of seeds. But, so far as I have observed, the seeds are not eaten until they are swollen or sprouted, when the outer covering bursts of itself. At this stage the starch is being converted into sugar, and this seems to be what the ants are after. They also seemed to be very fond of the yellow pollen-dust of the pine. The catkins of the long-leaved pine (Pinus australis) commenced falling in February, and I noticed ants congregated on them; so I took those just ready to discharge the pollen, and shook the dust on the mound in little heaps, which were soon surrounded by ants, crowding and jostling each other in their eagerness to obtain a share.

The colony in the glass jar seemed perfectly contented, not trying to make their escape at all. The earth was originally a little more than two inches in depth, but by the first of February these wonderful architects had reared their domicile to the height of six inches. They raised tier upon tier of chambers in so substantial a manner that they never fell in. One of the store-rooms in which they deposited the seeds I gave them was at the bottom of the jar, and the seeds were stored against the glass with no intervening earth between: it contained about a teaspoonful of millet. I gave this chamber the right degree of heat and moisture to sprout the seed by pouring a little water down the side of the jar until it penetrated the chamber, and then setting it near the fire. The ants soon appreciated the condition of this store-room, and many congregated there and seemed to be enjoying a feast. The next day the seeds were all brought to the surface and deposited in a little heap on one side of the jar, where many of them grew, making a pretty little green forest, which the ants soon cut down and destroyed. This chamber remained empty for three or four days, and was then again refilled with fresh millet and apple and croton seeds.