Ask any insect enthusiast how they became so interested in bugs, and he'll probably mention childhood hours spent watching ants. There's something fascinating about social insects, especially ones as diverse and evolved as the ants, the family Formicidae.
It's easy to recognize ants, with narrow waists, bulbous abdomens, and elbowed antennae. In most cases, when you observe ants you are only seeing the workers, all of which are female. Ants live underground, in dead wood, or sometimes in plant cavities. Most ants are black, brown, tan, or or red.
All ants are social insects. With few exceptions, ant colonies divide labor between sterile workers, queens, and male reproductives, called alates. Winged queens and males fly in swarms to mate. Once mated, queens lose their wings and establish a new nest site; males die. Workers tend to the colony's offspring, even rescuing the pupae should the nest be disturbed. The all-female workforce also gathers food, constructs the nest, and keeps the colony clean.
Ants perform important tasks in the ecosystems where they live. Formicids turn and aerate the soil, disperse seeds, and aid in pollination. Some ants defend their plant partners from attacks by herbivores.
Feeding habits vary in the ant family. Most ants prey on small insects or scavenge bits of dead organisms. Many also feed on nectar or honeydew, the sweet substance left behind by aphids. Some ants actually garden, using gathered leaf bits to grow fungus in their nests.
The complete metamorphosis of an ant may take from 6 weeks to 2 months. Fertilized eggs always produce females, while unfertilized eggs yield males. The queen can control the sex of her offspring by selectively fertilizing the eggs with sperm, which she stores after a single mating period.
White, legless larvae hatch from eggs, completely dependent on worker ants for their care. The workers feed the larvae with regurgitated food. In some species, pupae look like colorless, immobile adults. In others, pupae spin a cocoon. New adults may take several days to darken into their final color.
Special Adaptions and Defenses:
Ants employ a fascinating variety of behaviors to communicate and defend their colonies. Leafcutter ants cultivate a bacteria with antibiotic properties to keep unwanted fungi from growing in their nests. Others tend aphids, "milking" them to harvest sweet honeydew. Some ants use a modified ovipositor to sting, like their wasp cousins.
Some ants function as little chemical factories. Ants of the genus Formica use a special abdominal gland to produce formic acid, an irritating substance they can squirt as they bite. Bullet ants inject a strong nerve toxin when they sting.
Many ants take advantage of other species. Slave-making ant queens invade colonies of other ant species, killing the resident queens and enslaving her workers. Thief ants raid neighbor colonies, stealing food and even young.
Range and Distribution:
Ants thrive throughout the world, living everywhere except Antarctica, Greenland, Iceland, and a few isolated islands. Most ants live underground or in dead or decaying wood. Scientists describe nearly 9,000 unique species of Formicids; almost 500 ant species inhabit North America.