Formicidae

Latreille, 1802

Ants

Subfamily Guides

10

is a diverse of eusocial insects comprising an estimated 12,500–22,000 described globally, with approximately 14,000 species formally classified. Ants originated approximately 99–120 million years ago in the early Cretaceous period, evolving from -like ancestors. They are characterized by elbowed , a constricted petiole forming a narrow waist, and complex colonial organization. Ants occupy nearly all terrestrial except Antarctica, the Arctic, and extreme high-elevation tropical mountains, functioning as , scavengers, seed dispersers, and engineers.

Dolichoderinae by no rights reserved, uploaded by Jesse Rorabaugh. Used under a CC0 license.Neivamyrmex opacithorax by (c) Jake Nitta, some rights reserved (CC BY), uploaded by Jake Nitta. Used under a CC-BY license.Neivamyrmex pilosus by (c) April Nobile, some rights reserved (CC BY). Used under a CC-BY license.

Pronunciation

How to pronounce Formicidae: //fɔːˈmɪsɪdiː//

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Identification

Ants are distinguished from other Hymenoptera by the combination of elbowed , a pronounced petiole with node-like structure(s), and eusocial colony organization with wingless . They differ from in having the petiole positioned between the mesosoma and metasoma rather than as a simple constriction, and from (which convergently evolved eusociality) by their elbowed rather than bead-like antennae and the presence of a metapleural gland. Male ants can be differentiated from females by typically having one more antennal segment, larger , and more wasp-like overall appearance.

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Appearance

Ants possess a distinctive three-segmented body plan: , mesosoma (), and metasoma () connected by a narrow petiole with one or two node-like structures. The are elbowed (geniculate), with a long scape and shorter . Most are wingless; reproductive queens and males typically have two pairs of membranous wings, though males of some lineages have evolved winglessness. Body size ranges from less than 1 mm to over 30 mm depending on and . Coloration is highly variable, including black, red, yellow, brown, and metallic forms.

Habitat

Ants occupy virtually all terrestrial including tropical rainforests, temperate forests, grasslands, deserts, and Arctic tundra. They are absent from Antarctica, the Arctic, and extreme high-elevation tropical mountains. Specific associations vary by : some are arboreal (e.g., Colobopsis in forest ), others ground-nesting in soil or leaf litter, and many utilize dead wood (e.g., Camponotus). such as (Linepithema humile) thrive in disturbed habitats and riparian corridors.

Distribution

Global distribution across all continents except Antarctica. Approximately 300 occur in California, 132 in Slovenia, and 183 species documented from 42 in comprehensive regional surveys. Highest diversity occurs in tropical regions; the genus Melophorus alone contains 93 described species in Australia. The originated in the early Cretaceous and has since colonized nearly all ice-free land surfaces.

Seasonality

Activity patterns vary by and climate. Temperate species typically show seasonal activity from spring through fall, with dormancy in winter. Tropical species may remain active year-round. Activity timing is influenced by temperature, moisture, and resource availability. Some species exhibit foraging, others ; segregation in activity timing has been documented as a mechanism reducing in .

Diet

Highly variable across . Many ants are and scavengers, consuming other arthropods and organic matter. Some are specialized predators (e.g., army ants). Others engage in mutualistic relationships: -tending ants consume honeydew, while leafcutter ants (Atta, Acromyrmex) cultivate fungus gardens on plant material. Seed-harvesting ants (e.g., Pogonomyrmex) collect and store seeds. Nectar and other plant exudates are commonly exploited.

Life Cycle

Complete with four stages: , larva, pupa, and . Colonies are and may persist for years to decades. Developmental time varies by , temperature, and . is typically synchronized seasonally, with of winged queens and males occurring during specific environmental conditions. Colony founding may be independent (single ) or dependent (pleometrosis, , or social ).

Behavior

Eusocial colonies exhibit cooperative care, overlapping , and reproductive division of labor. Communication occurs primarily through chemical and tactile signals; vision is generally poor. guide foragers to food sources and back to nests. trigger defensive responses. Nest-mate recognition relies on cuticular hydrocarbons. Some exhibit specialized defensive , including autothysis (self-sacrifice by body rupture) in Colobopsis explodens, where minor explode to release toxic, sticky secretions when threatened.

Ecological Role

Ants function as engineers and keystone organisms in many terrestrial ecosystems. Roles include: seed (myrmecochory), soil aeration through nest construction, nutrient cycling via decomposition, of herbivorous insects, and linking as both and prey. In tropical forests, ants and may constitute up to one-third of total animal . Some engage in protective mutualisms with plants or sap-feeding insects.

Human Relevance

Ants have significant economic and ecological impacts. Beneficial roles include of agricultural pests and soil improvement. Pest cause problems: ants such as (Linepithema humile), (Solenopsis invicta), and yellow crazy ants disrupt native , agriculture, and human infrastructure. Some species infest structures (carpenter ants, Camponotus). Stinging species pose health risks. Ants are important model organisms for studying social evolution, collective , and communication.

Similar Taxa

  • Vespidae (wasps)Also Hymenoptera with constricted waist, but lack the distinct petiole node(s) of ants and typically have smooth rather than elbowed ; most wasps are solitary or have simpler social organization
  • Isoptera/Termitidae (termites)Convergently eusocial with wingless , but have bead-like () rather than elbowed , lack the metapleural gland, and have different wing venation in reproductives
  • Mutillidae (velvet ants)Females are wingless and -like in appearance, but have straight , lack the petiole node structure, and are solitary rather than social insects

More Details

Male ant underrepresentation

Males are known for only 27% of described , and no comprehensive identification resources existed for males of most bioregions until recent male-based keys to and level were developed for the New World.

Explosive defensive specialization

The 'exploding ants' of the Colobopsis cylindrica group, including the model C. explodens, represent a remarkable case of autothysis—minor actively rupture their body wall to release toxic, sticky secretions when threatened, sacrificing themselves to defend the colony.

Invasive ant impacts

form supercolonies where neighboring colonies cooperate rather than compete, enabling rapid expansion and displacement of native , particularly along riparian near urban areas.

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