Formicidae

Formicidae is a family of eusocial insects within the order Hymenoptera, commonly known as ants. With approximately 12,000 described species, ants are among the most diverse and ecologically successful terrestrial organisms. They occupy nearly all environments, from deserts to tropical forests, and form colonies that can range from a few dozen individuals to many millions. Nests vary from subterranean tunnels to mound-like structures and arboreal nests in wood or vegetation.

Ants are distinguished by elbowed antennae and a narrow waist formed by one or two petiole segments linking the thorax to the abdomen. The family includes several subfamilies, such as Formicinae (Formica, Lasius), Myrmicinae (Pheidole, Solenopsis), Dolichoderinae (Linepithema), and Ponerinae (Odontomachus).

Society and behavior: Ants are eusocial, living in colonies that include queens for reproduction, workers, and, in many species, males. Reproduction is often seasonal, with winged individuals dispersing to found new colonies. Communication relies on chemical pheromones and tactile signals, and foraging is highly organized. Some lineages farm fungus (leaf-cutter ants) or cultivate aphids for honeydew; others are efficient scavengers and predators.

Ecology and interactions: Ants influence ecosystems through soil modification, predation, seed dispersal, and mutualisms. They form relationships with plants, fungi, and bacteria, and can be commensals, mutualists, or pests. Invasive species such as the Argentine ant Linepithema humile and the red imported fire ant Solenopsis invicta can disrupt native communities.

Evolution and fossil record: Ants first appeared in the mid-Cretaceous period, with fossils dating to about 100–130 million years ago. They rapidly diversified into many subfamilies and genera, aided by eusociality and associations with flowering plants and fungi. Modern lineages continue to be studied for insights into social behavior and ecology.