Midnight. The moon was covered with clouds. The cool wind from the south has almost nothing to rustle - the vegetation of the North American Mojave Desert is sparse. Grasshopper mice squeak, kangaroo rats grappled with a squeal. And in the meantime, the sandy rattlesnake has already crawled out to hunt and is watching for both those and others.
But what does this struggle for existence mean in comparison with the tragedies that are unnoticeable to us in the world of a different scale - in the anthill? A ray of light from a small flashlight attached to the head helps the myrmecologist in his work.
A sketched glance alone is not enough; a good chance is also needed so that a person can spy on such, for example, a moment full of drama: two ants collided on the run - a worker and a wandering one. They instantly felt and sniffed each other - and rushed in different directions. A working foraging ant rushes to his native anthill to notify that the forage path, marked with its smell, will bring a terrible disaster to the family: hordes of voracious enemies will descend along it into the anthill. The stray scout is in a hurry to report the success of his reconnaissance and put together a marching column for a plundering raid. Mobilization is happening rapidly: the soldiers flock in thousands, and in a matter of seconds an army of one hundred thousand jaws rushes towards the doomed anthill.
And there - panic and panic. They don't even think about resistance - the enemy is larger, his jaws are more powerful. The owners flee in terror, taking eggs, larvae and pupae. Meanwhile, hostile lava is approaching their dwelling (we will venture to use this word, which at once reminds of a cavalry attacking order and a volcanic eruption). The robbers do not pursue the loaded fugitives: how many will they save? In the depths of the anthill there will be so much prey that it will not be carried away!
A quarter of an hour later, the raid was completed. For fifteen meters the squads of winners were stretched, bending under the weight of trophies. They hurry to their marching nest.
Of the fifteen thousand species of ants, about three hundred live by such a barbaric robbery of other people's homes. Stray ants have their own way of dealing with the need to feed a hole in their mouths. For voracious small predators, the systematic collection of edibles is not suitable, as, say, reaper ants or woodworms do. Serve large food supplies to stray ants. And where to get them, if not in someone else's anthill? In addition, there proteins, fats, vitamins and minerals are conveniently "packaged" in eggs, larvae and pupae.
In temperate latitudes, roaming robbers of the insect kingdom are rare, in small families. They live best of all in South and Central America and Africa. Stray ants have two distinguishing features. Their very name speaks about the first: from time to time - and some species with constant regularity - move to a new habitat when prey on the old one becomes scarce. Such a wandering is an impressive event. Adult ants drag the entire "belongings" of the family for many hundreds of meters - this is a great migration on the ant scale.
The second feature of stray ants is the ability to instantly mobilize for a crushing raid. Worker ants feed mainly on plant foods or dead insects. And the prey of their stray brethren, as a rule, is alive and rebuffs. To defeat her, it takes a precisely coordinated attack of hundreds, if not thousands of ants. These organized attack skills also work against the resident ant.
Promotional video:
The tactics of stray ants are varied. Some hunt exclusively at night and send only a shock column from the nest. Others - for example, tropical etzitons, terrifying even mammals and humans - hunt during the day and advance in an all-devouring multi-meter front. To take someone else's anthill by surprise, stray ants need to attack as unexpectedly as possible - and for this they swiftly gather in a marching army. How do they achieve such swift and cohesive action?
Recently, American biologists from the University of Connecticut have clarified how mobilization occurs in stray ants. The ant-scout, while surveying the area, leaves behind a fragrant path, all scouts scurry back and forth along their own and other people's marked paths. So far, everything is the same as with the worker ants. But then the scout comes across prey, which can only be dealt with by joint efforts. He immediately rushes to his nest. At the same time, it is not at all necessary for him to stop every fellow he meets and "explain" the plan of the upcoming operation. For him it will be done by a special "recruiting pheromone", which he begins to emit instead of the usual pheromone. The scout's trail now becomes a signal for mobilization - the ant that stumbles upon such a path immediately abandons all its affairs and behaves like this,as if he had discovered the most valuable prey and, in turn, on the run to the goal marks the way with the "recruiting pheromone". And since the ant routes are incredibly messed up, sooner than you read this explanation, thousands of ants will join the army.
Sometimes, as a result of such blind chemical mobilization, the army is oversized. The ants left out of work form a reserve, which huddles near the place of battle or robbery, ready to come to the rescue or be in the wings - in case of rich trophies. If the raid is completed without the help of the reserve, the ants do not scatter for the routine search for new food, but with unspent fervor, they rush in a column for prey worthy of a collective attack.
Most importantly, the "recruiting pheromone" is less stable than the one that is used to mark regular scouting lanes. Yes, he is not needed for a long time, otherwise, having organized a swift attack, after that he will simply send new "recruits", as they say, wave his fists after a fight.
But, despite such an effective mobilization mechanism, stray ants are not always as lucky as during the described night raid in the Mojave Desert. Sometimes their forays end in nothing. After all, the victims, so to speak, are not a bastard: not all panic and cowardly run away, many species of hardworking ants have succeeded in the art of defense.
Desert reaper ants, for example, fill up the entrance to their anthill with pebbles at night. Other types of reapers are more arrogant - the entrance is left open, even if they do not work outside the anthill at night, and they fill it up only when the enemy approaches. There are reapers whom nature has not deprived of size and well armed. They do not walled up from the aggressor at all, but boldly counterattack. At night, they post a dozen or two patrols at the entrance, who, in case of danger, call hundreds of soldiers who boldly go into battle. Some defenders perish - new ones appear. And so sometimes until the morning, when the first rays of the sun illuminate thousands of bitten and decapitated corpses of defenders and attackers, covering the space in front of the anthill. And honey-collecting ants also use chemical weapons: having bitten an enemy, they inject destructive acid into his wound. Those,those with weaker jaws flee.
Scientists carried out three experiments in an anthill of kamponotus created in the laboratory. They let out one stray ant, fifty stray ones, and, finally, a hundred woodworms (just as peaceful as campotus, but competing with them in collecting food, which sometimes causes fights) near the anthill. Kamponotus reacted as violently to the appearance of one wandering ant as to the appearance of fifty: they proceeded to an organized evacuation of the entire family belongings - eggs, larvae, pupae. They knew that one roving ant does not exist - it will lead thousands. And the owners of the anthill did not react to woodworms. The mechanism that eliminates false panic and allows you to distinguish roaming marauders from all others works accurately. Evacuation should only be a last resort - after all, it means going out into an open space, which is unsafe:while you carry your feet away from the stray raiders, you will just run into another trouble with all the offspring and the uterus. You never know who love to feast on ant - snakes, and scorpions, and wolf spiders!
In terms of organization, all are superior to feidole ants. At the first alarm signal, they only prepare the family good for removal: the larvae and pupae are brought to the exit and only a small part to the surface. The general flight does not begin until a new confirmation of the danger, as if hoping for a miracle: what if that spy who "spotted" their anthill was pecked at the same moment by a bird or licked by a frog?..
Evacuation is fraught with another danger: robbers often stay overnight in a plundered anthill. By the next night they will certainly move on, but where are the owners to go until then? In the forest, on the mountain slopes, refugees sit under fallen leaves or large stones. But what about the feydole ants that live in the desert? No leaves, no stones, and staying in the daytime in the direct rays of the sun is certain death! Feydole is pulling out five or six dwellings at once within a radius of several meters. In alarm, they scatter to spare anthills, and after a day or two they gather in one of them. The still unexplained semi-nomadic way of life of these ants is associated with the abundance of housing. About once a week, the whole family moves to a new anthill, which one cannot be predicted in advance. Why such risky and troublesome "relocations?" Can,for practicing evacuation techniques? Or an attempt to confuse enemy scouts? Too expensive for training. For deception - naive.
This is not the only mystery in the strategy and tactics of ant wars. The secrets of the ant military art are still to be discovered and discovered. And in anthills specially created in the laboratory, and in natural conditions, a scientist-myrmecologist patiently bends with a lamp, observing the inaudible night wars.