For ants, the basic unit of life is the colony. Like an organism, this collective body must be studied as a whole to understand the biology of colonial species. Dense ant communities offer the closest thing to a “civilisation” in the insect world, and in many respects their societies resemble our own. As with human groups, ant communities have specialised in three main strategies for obtaining food: gathering, hunting, and cultivation.

Ants are among the most highly evolved social insects, and social insects themselves form the largest and most complex insect groups. Their success rests on three traits: adults care for the young; two or more generations of adults coexist in the same nest; and colony members are divided into a reproductive “royal” caste and a sterile worker caste.

Entomologists define such tightly organised societies as eusocial (“truly social”). Four main insect groups qualify: ants, termites, certain bees, and some wasps. All ants are eusocial and belong to the Formicidae family in the order Hymenoptera. Around 9,500 species are currently known, though at least twice that number likely remain undescribed. Most live in tropical regions.

Specialists believe that ants’ rise as the dominant insect group is due to their highly developed colonial life, built on individual sacrifice for the common good. They have also found that each colony is governed by a Darwinian balance between collective survival and internal struggles for control. Polygynous colonies—with several fertile queens—can persist for very long periods, reaching enormous size and population.

The ants’ dwelling is called a nest. It offers shelter, security, protection from enemies, a stable microclimate, a safe space for reproduction, and storage for food. Some nests are simple, with just a few galleries, while others form complex systems of chambers with flat floors and interconnecting tunnels. Nests may lie beneath stones, next to walls, inside wooden beams, under trees, or as earthen mounds across open fields and plains. They can stretch over many metres and reach depths of up to five metres, ending in chambers about a metre long and thirty centimetres high.

Inside, the microclimate is carefully regulated to ensure ideal conditions for life and the rearing of offspring. Forest ant mounds, for example, may have ventilation openings that can be opened or closed to maintain stable temperature and humidity. Ant societies are generally divided into three castes. Queens found new colonies and then serve mainly as egg-layers. Winged males undertake a single nuptial flight, fertilise the queen for life, and soon die. Sterile female workers carry out all the colony’s tasks—nursing, cleaning, building, defending, and foraging.

Queens are larger than the other castes and usually winged, losing their wings after mating. To establish a new colony, a young queen digs a small chamber in the earth where she lays her first eggs. Winged males are much smaller, short-lived, and die shortly after mating. Workers are wingless, sterile, and perform the heavy labour.

Smaller colonies may have only these three types, but larger colonies can contain several worker sub-castes of different sizes, shapes, and behaviours. Ant longevity is remarkable: some workers live up to seven years, and queens may reach fifteen. The record for a captive queen is a Lasius niger (European black ant) that lived 29 years in an artificial colony in Switzerland. Over their lifetime, queens may produce a few hundred workers—or, in the case of leaf-cutting ant queens in Central and South America, up to 150 million.

There are numerous kinds of ants, each with its own way of life and specialised role within the colony. Carpenter ants excavate long tunnels in decaying wood. Warrior ants hunt other insects, storing and transporting the remains when the colony moves. “Dairy” ants herd plant lice, leading them to feed and protecting them in exchange for sweet secretions. Harvester ants stockpile large quantities of seeds. Leaf-cutting ants chew leaves into a paste used to cultivate the fungi that serve as their primary food.

Other forms include thieves or beggars that live underground in the nests of other species; honey ants that store sweet juices in the distended bodies of young workers; slave-raiding ants that capture the eggs and larvae of other species and raise them as workers; and doorkeeper or guard ants that use their oversized heads like a living plug, sealing and disguising the nest entrance.

When amber is rubbed with a woollen cloth, it acts as a conductor of electricity and attracts small, lightweight objects such as bits of paper. This simple experiment, already known to the ancient Greeks more than two thousand years ago, was humanity’s first encounter with electricity of its own making.

The Greeks called amber elektron. Over time, this term was transferred to the phenomenon we now call “electricity,” and later adapted into the word “electronic”—which, in a sense, could be understood as “pertaining to amber.”