Nomad ants - the real life of tropical predators

Nomad ants, regularly migrating in millions of colonies, live in the tropical zone of Africa, Asia and America. Insects do not build permanent nests, their sedentary phase of life lasts no more than 2-3 weeks. They move during the day, arrange a bivouac from their own bodies for spending the night, in the center of which there is a uterus. A horde that travels 1–3 km leaves nothing alive. Powerful mandibles carve not only insects, but small mammals, birds. Stray ants are called killers, often exaggerating their danger.

Description

Several related groups of true ants are united by a similar lifestyle called nomad ants syndrome. Their characteristic feature is regular migrations. Numerous insect colonies, reaching several million, move within 1-2 weeks. They carry eggs, larvae, and a queen with them. Nomadic individuals do not build anthills, mating with bodies, they arrange a nest for numerous family members and the uterus.

Adult

The body of an adult ant consists of three sections: head, chest (mesosome) and abdomen. The stalk connecting the thoracic segments and the abdomen is called petiol. The chitinous exoskeleton protects and supports the body of the insect. On the ant’s head there are antennae consisting of 8-10 segments. These are sensory organs that capture vibrations, chemical odors.

Interesting fact. Most stray ants do not have organs of vision, or they are greatly reduced. Blind insects orient themselves in space using antennae. They communicate with each other by the release of pheromones.

The upper jaws of the mandible ants vary in size, but are always well developed. In working individuals, they are intended for the transfer of eggs and larvae, food. For soldiers, this is a powerful weapon. Strong mandibles help tear apart enemies. Insects have 3 pairs of legs, on the legs there are claws that help to move on a vertical surface. The abdomen of some species ends in a sting.

Interesting fact. Ants of the genus Dorylus do not open their closed jaws even after death.

Communication system

In the ant's body there are 75 glands, they secrete various substances, including pheromones and repellents. Nomadic species have dozens of special signal odors produced in various situations. Using pheromones, scouts indicate the direction of movement of the entire column, report on the location of the prey.

Ant hierarchy

A family of nomad ants consists of hundreds of thousands or millions of individuals. They all obey a strict hierarchy and act as a single harmonious organism. The basis of a large colony is made up of working ants. These are barren females. Of these, specialized groups are formed: workers, foragers, scouts, soldiers. Males are several times larger than representatives of the working caste. The main figure of the family is the queen. She is the only female involved in the birth of new members of the colony. The Queen's life is 15-20 years.

A significant part of the family is brood - eggs, larvae, pupae. Workers take care of him.The family has clearly divided responsibilities, each insect is engaged in its own labor. A highly organized colony is capable of building bridges and nests from the bodies of ants, resisting enemies, and hunting.

Classification

In the world there are three subfamilies of tropical nomad ants. The main classification occurs according to the habitat:

1. Aenictus are small and medium insects common in Asia, Australia and Africa. Working individuals are yellow-brown in color, their body length does not exceed 3.5 mm. The males and females of the genus are much larger, reaching 25 mm. Differences are also apparent in the anatomical structure - in working ants, the stalk between the chest and abdomen consists of two segments, in males and females of one. The subfamily united about 180 species.
2. Dorylinae - the main habitat regions are tropical Asia and Africa. A large group includes 800 species. The most famous genus is Dorylus. Depending on the hierarchy, ants vary significantly in size. Workers 3 mm, soldiers 13 mm, males 30 mm, Samkido 50 mm. The number of individuals in one migratory colony is about 20 million.
3. Ecitoninae - insects are found in the New World in the United States, the southern border of habitat is Argentina and Chile. American predators spend most of their life on the road and hunting. During the migration, places in the column are clearly allocated. Worker ants move in the middle and bear offspring. Soldiers on the sides guard relatives from attack by enemies. The color of the imago from brown to black.

Lifestyle

The syndrome of nomad ants is manifested in the behavior and characteristics of the reproduction of insects. Its signs:

• collective foraging;
• construction of temporary bivouac nests;
• regular change of phases of settled and migration;
• submission of the reproductive cycle to the schedule of movement of the colony.

A family of several million people requires a huge amount of food. To get it in one place is unrealistic, so insects constantly migrate. The movement of the insect column is like a running creek. Its width is 30-100 cm, length is up to 45 m. Nomads on different continents differ in speed of movement. African ants Dorylinae - 20 m / h, American Ecitoninae - 100-150 m / h.

As dusk sets in, the construction of the bivouac begins. A temporary nest in the shape of a sphere from the bodies of working individuals is being built in a secluded place. Inside is placed the queen and the offspring. The bivouac has several entrances. The diameter of the bivouac is about 1 meter, for the construction requires 500-700 thousand ants. Siafu African ants dig nests in soft land. Blind diggers are quickly preparing a shelter for a huge family of up to 20 million individuals. Their distinguishing feature is the absence of a sting. It is replaced by powerful mandibles, painful bites cause inconvenience even to elephants. The jaws easily cut the covers of insects and animals, tear pieces of flesh from them.

Nomad ants at any age eat exclusively meat food. For small larvae, hunters get spiders, caterpillars, beetles, locusts, scorpions. Birds that make nests on the ground, small vertebrates (lizards, snakes, rodents) become the victims of predators. The colony cleans the found corpses of large animals, leaving behind only bones.

Propagation Features

The reproductive function of the colony is entrusted to the queen uterus. Tropical nomad ants have one queen, while other species may have several. A large winged female mates with a male during the first flight. Until the end of her life, she spends stored sperm. The adult fertilized queen drops her wings. She is always protected by working ants. During movement, the cylindrical elongated abdomen of the female is slender. When hundreds of thousands of eggs mature, it swells. By the beginning of the stationary phase, the larvae turn into cocoons and do not require feeding. All meat obtained by hunters is given to the queen.

Ants belong to hymenoptera with a complete transformation. This means that their life begins with the phase of the egg, then a larva appears.Ants turn into adults after pupation. Egg formation begins during the sedentary period. Fertility of the female is 200-300 thousand pieces. The embryonic period lasts up to three weeks. By the time of the new migration, larvae appear from the eggs.

This process is synchronized by the development of pupae, and adults emerge from the cocoons of the previous masonry. To feed the larvae, the colony sets off. By the time of their pupation, the column finds a parking place.

Once a year, the queen makes a special masonry from which reproductive females and males emerge. With age, they leave the family and form their own colonies.

Benefit and danger to humans

Residents of villages located in tropical forests are well aware of the possibilities of the ant horde. If their homes are in the path of insects, they take livestock and leave the village for a while. After the invasion of tropical nomads, all the parasites in the houses disappear. Flies, fleas, cockroaches, spiders, rats are destroyed. Ants do not eat plants, so the fields are safely exempt from phytophage pests.

The beneficial effects of stray insects do not preclude danger to humans. Once on the path of the colony, a person runs the risk of being bitten by hundreds of individuals. Nomadic ants do not immediately bite the prey. They crawl under clothes in large numbers and act on a signal. For people prone to allergies, such an attack results in anaphylactic shock. Attacks on humans and animals are rare. The main prey of ants is other insects. Tropical stray ants cleanse the forests of animal corpses, destroy the sick and weak individuals.