The Ways of the Ant
ERY many performances on the part of the ant seem to us without reason; undoubtedly many of our performances seem likewise to her. But the more understandingly we study her and her ways, the more we are forced to the conclusion that she knows what she is about; I am sure that none of us can sit down by an ant-nest and watch its citizens come and go, without discovering things to make us marvel.
By far the greater number of species of ants find exit from their underground burrows, beneath stones in fields. They like the stone for more reasons than one; it becomes hot under the noon sun and remains warm during the night, thus giving them a cozy nursery in the evening for their young. Some species make mounds, and often several neighboring mounds belong to the same colony, and are connected by underground galleries. There are usually several openings into these mounds. In case of some of the western species which make galleries beneath the ground, there is but one opening to the nest and Dr. McCook says that this gate is closed at night; at every gate in any ants' nest, there are likely to be sentinels stationed, to give warning of intruders.
As soon as a nest is disturbed, the scared little citizens run helter skelter to get out of the way; but if there are any larvæ or pupæ about, they are never too frightened to take them up and make off with them; but when too hard pressed, they will in most cases drop the precious burden, although I have several times seen an ant, when she dropped a pupa, stand guard over it and refuse to budge without it. The ant's eggs are very small objects, being oblong and about the size of a pin point. The larvæ are translucent creatures, like rice grains with one end pointed. The pupæ are yellowish, covered with a parchment-like sac, and resemble grains of wheat. When we lift stones in a field, we usually find directly beneath, the young of a certain size.
There are often, in the same species of ants, two sizes; the large ones are called majors and the smaller minors; sometimes there is a smaller size yet, called minims. The smaller sizes are probably the result of lack of nutrition. But whatever their size, they all work together to bring food for the young and in caring for the nest. We often see an ant carrying a dead insect or some other object larger than herself. If she cannot lift it or shove it, she turns around, and going backwards, pulls it along. It is rarely that we see two carrying the same load, although we have observed this several times. In one or two cases, the two seemed not to be in perfect accord as to which path to take. If the ants find some large supply of food, many of them will form a procession to bring it into the nest bit by bit; such processions go back by making a little detour so as not to meet and interfere with those coming. During most of the year, an ant colony consists only of workers and laying queens, but in early summer the nest may be found swarming with winged forms which are the kings and queens. Some warm day these will issue from the nest and take their marriage flight, the only time in their lives when they use their wings; for ants, like seeds, seem to be provided with wings simply for the sake of scattering wide the species. It is a strange fact, that often on the same day swarms will issue from all the nests of one species in the whole region; by what mysterious messenger, word is sent that brings about this unanimous exodus, is still a mystery to us. This seems to be a provision for cross-breeding; and as bearing upon this, Miss Fielde discovered that an alien king is not only made welcome in a nest, but is sometimes seized by workers and pulled into a nest; this is most significant, since no worker of any other colony of the same species, is permitted to live in any but its own nest.
After the marriage flight, the ants fall to the ground and undoubtedly a large number perish; however, just here our knowledge is lamentably lacking, and observations on the part of pupils as to what happens to these winged forms will be valuable. In the case of most species, we know that a queen finds refuge in some shelter and there lays eggs. Mr. Comstock once studied a queen of the big, black carpenter ant which lives under the bark of trees. This queen, without taking any food herself, was able to lay her eggs and rear her first brood to maturity; she regurgitated food for this first brood, and then they went out foraging for the colony. However, Miss Fielde found that in the species she studied, the queen could not do this; a question most interesting to solve is whether any of the young queens, after the marriage flight, are adopted into other colonies of the same species. As soon as a queen begins laying eggs, she sheds her then useless wings, laying them aside as a bride does her veil.
When we are looking for ants' nests beneath stones, we often stumble upon a colony consisting of citizens differing in color. One has the head and thorax rust-red with the abdomen and legs brown; associated with this brown ant, is a black or ash-colored species. These black ants are the slaves of the brown species; but slavery in the ant world has its ameliorations. When the slave makers attack the slave nest, they do not fight the inmates unless they are obliged to. They simply loot the nest of the larvæ or pupæ, which they carry off to their own nests; and there they are fed and reared, as carefully as are their own young. The slaves seem to be perfectly contented, and conduct the household affairs of their masters with apparent cheerfulness. They do all the taking care of the nest and feeding the young, but they are never permitted to go out with war parties; thus they never fight, unless their colony is attacked by marauders.
If one chances upon an ant battle, one must needs compare it to a battle of men before the invention of gunpowder; for in those days fighting was more gory and dreadful than now, since man fought man until one of the twain was slain. There is a great variation in military skill as well as in courage shown by different species of ants; the species most skilled in warfare, march to battle in a solid column and when they meet the enemy, the battle resolves itself into duels, although there is no code of ant honor which declares that one must fight the enemy single-handed. Although some ants are provided with venomous stings, our common species use their jaws for weapons; they also eject upon each other a very acid liquid which we know as formic acid. Two enemies approach each other, rear on their hind legs, throw this ant vitriol at each other, then close in deadly combat, each trying to cut the other in two. Woe to the one on which the jaws of her enemy are once set! For the ant has bull-dog qualities, and if she once gets hold, she never lets go even though she be rent in pieces herself. At night the ant armies retreat to their citadels, but in the morning fare forth again to battle; and thus the war may be waged for days, and the battlefield be strewn with the remains of the dead and dying. So far as we are able to observe, there are two chief causes for ant wars; one is when two colonies desire the same ground, and the other is for the purpose of making slaves.
Perhaps the most interesting as well as most easily observed of all ant practices, are those that have to do with plant-lice, or aphids. If we find an ant climbing a plant of any sort, it is very likely that we shall find she is doing it for the purpose of tending her aphid herds. The aphid is a stupid little creature which lives by thrusting its bill or sucking tube into a stem or leaf of a plant, and thus settles down for life, nourished by the sap which it sucks up; it has a peculiar habit of exuding from its alimentary canal drops of honey-dew, when it feels the caress of the ant's antennæ upon its back. I had one year under observation, a nest of elegant little ants with shining triangular abdomens which they waved in the air like pennants when excited. These ants were most devoted attendants on the plant-lice infesting an evening primrose; if I jarred the primrose stem, the ants had a panic, and often one would seize an aphid in her jaws and dash about madly, as if to rescue it at all hazards. When the ant wishes honey-dew, she approaches the aphid, stroking it or patting it gently with her antennæ, and if a drop of the sweet fluid is not at once forthcoming, it is probably because other ants have previously exhausted its individual supply; if the ant gets no response, she hurries on to some other aphid not yet milked dry.
This devotion of ants to aphids has been known for a hundred years, but only recently has it been discovered to be of economic importance. Professor Forbes, in studying the corn root-louse, discovered that the ants care for the eggs of this aphid in their own nests during the winter, and take the young aphids out early in the spring, placing them on the roots of smartweed; later, after the corn is planted, the ants move their charges to the roots of the corn. Ants have been seen to give battle to the enemies of the aphid. The aphids of one species living on dogwood are protected while feeding by stables, which a certain species of ant builds around them, from a mortar made of earth and vegetable matter.
References—Ants, W. M. Wheeler, Ant Communities, McCook.
Field Observations on Ants
Leading thought—However aimless to us may seem the course of the ant as we see her running about, undoubtedly if we understood her well enough, we should find that there is rational ant-sense in her performances. Therefore, whenever we are walking and have time, let us make careful observations as to the actions of the ants which we may see.
Method—The following questions should be written on the blackboard and copied by the pupils in their note-books. This should be done in May or June, and the answers to the questions worked out by observations made during the summer vacation.
1. Where do you find ants' nests? Describe all the different kinds you have found. In what sort of soil do they make their nests? Describe the entrance to the nest. If the nest is a mound, is there more than one entrance? Are there many mounds near each other? If so, do you think they all belong to the same colony?
2. When the nest is disturbed, how do the ants act? Do they usually try to save themselves alone? Do they seek to save their young at the risk of their own lives? If an ant, carrying a young one is hard pressed, will she drop it?
3. Make notes on the difference in appearance of eggs, larvæ and pupae in any ants' nest.
4. In nests under stones, can you find larvæ and pupæ assorted according to sizes?
5. How many sizes of ants do you find living in the same nest?
6. What objects do you find ants carrying to their nests? Are these for food? How does an ant manage to carry an object larger than herself? Do you ever see two ants working together carrying the same load?
7. If you find a procession of ants carrying food to their nest, note if they follow the same path coming and going.
8. If you find winged ants in a nest, catch a few in a vial with a few of the workers, and compare the two. The winged ants are kings and queens, the kings being much smaller than the queens.
9. If you chance to encounter a swarm of winged ants taking flight, make observations as to the size of swarm, the height above the ground, and whether any are falling to the earth.
10. Look under the loose bark of trees for nests of the big, black carpenter ant. You may find in such situations a queen ant starting a colony, which will prove most desirable for stocking an artificial ant's nest.
11. If you find ants climbing shrubs, trees or other plants, look upon the leaves for aphids and note the following points:
a. How does an ant act as she approaches an aphid?
b. If the aphids are crowded on the leaf, does she step on them?
c. Watch carefully to see how the ant touches the aphid when she wishes the honey-dew.
d. Watch how the aphid excretes the honey-dew, and note if the ant eats it.
e. If you disturb aphids which have ants tending them, note whether the ants attempt to defend or rescue their herds.
f. If there are aphis-lions or ladybird larvæ eating the aphids, note if the ants attack them.
12. If you find a colony of ants under stones where there are brown and black ants living together, the black members are the slaves of the brown. Observe as carefully as possible the actions of both the black and the brown inhabitants of the nest.
13. If you chance to see ants fighting, note how they make the attack. With what weapons do they fight? How do they try to get at the adversary?
14. Write an English theme covering the following points: How ants take their slaves; the attitude of masters and slaves toward each other; the work which the slaves do, and the story of the ant battle. How ants care for and use their herds.
References—American Insects, Kellogg, Manual for the Study of Insects, Comstock; Ants, McCook; True Tales, Jordan, page 6.