According to Virgil, the behaviour of a colony of ants can be a warning of impending storms. In his Georgics he tells us that if rain is to be expected: Saepius et tectis penetralibus extulit ova Angustum formica terens iter.
His comments were loosely but elegantly translated into English by John Dryden in the 17th century, the latter's version being: For ere the rising winds begin to roar, The careful ant her secret cell forsakes
And drags her eggs along the narrow tracks.
This alleged frenetic energy on the part of the insects is no doubt related to the superstition, common in many cultures, that stepping on ants will bring the rain.
If you accept Virgil's thesis, then it may well be that the reason the ants are there to be stepped on in the first place is that they know the rain is coming, and in such circumstances run conspicuously to and fro, carrying their eggs to a more protected spot. And this may well be so; it is not impossible that their behaviour is prompted by subtle changes in humidity that are undetectable to you and me.
Some keen observers also report that ants seem to run faster in warm weather than they do when it is cool, even to the extent that an approximation to the air temperature may be obtained by timing the speed of movement of these busy insects. If so, it may be that it is in this thermometric skill that we can find the answer to periodic swarms of these particular insects.
Continuation of the species depends on the successful mating "on the wing" of the winged males and queens in summer, an exercise which, as even common sense would suggest, is most effectively accomplished in dry and calm conditions. The eager potential procreators are carefully pampered in their nests by the wingless workers, often for several weeks, until conditions are exactly right.
The workers monitor the temperature and humidity outside, waiting for the perfect mating weather to arrive. Then, when a period of stable anticyclonic conditions arrives, the worker ants release a chemical into the air that stimulates the males and queens to emerge simultaneously from hundreds of nests over many square miles. The result is a swarm, common in summer-time, during which many an antly nuptial is consummated.
And allegedly, the ant also demonstrates its mastery of meteorology in less dramatic ways. We are told that when they expect bad weather, ants going about their normal business travel in straight, regimented lines; but if good weather is on the way, they spread out and range over wide areas.