Family Formicidae - Ants
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Class Insecta (Insects)
Order Hymenoptera (Ants, Bees, Wasps and Sawflies)
No Taxon (Aculeata - Ants, Bees and Stinging Wasps)
Superfamily Formicoidea (Ants)
Family Formicidae (Ants)
Synonyms and other taxonomic changes
recent advances in taxonomy summarized in(1)
Explanation of Names
goes back to Old English aemete, aemette(2)
-- perhaps a compound of ai-/ā-
'off, away' + maetan/mait
'to cut, engrave' (hypothetical root), that may have referred to either the ants' biting habits or indented body(2)
; an archaic Modern English variant: emmet
over 700 spp. in 80 genera in our area(3)(4)
; 14,000 spp. in ~300 genera of 20+ subfamilies(5)
; faunal checklists for many US states provided on(6)
, QC checklist here(7)
Overview of our fauna:
Taxa not yet in the guide are marked (*) and linked to AntWeb pages(3)
Tribe Acanthostichini Acanthostichus
Tribe Cerapachyini Cerapachys
Tribe *Bothriomyrmecini *Bothriomyrmex
Tribe Dolichoderini Dolichoderus
Tribe *Ectatommini *Gnamptogenys
Tribe Camponotini Camponotus
Tribe *Basicerotini *Eurhopalothrix
Tribe Pseudomyrmecini Pseudomyrmex
Ants can be distinguished from wasps by the constriction ("cinctus") of the rear portion of the waist or second abdominal segment, to form a well-distinguish node or scale, this segment named the petiole; the third abdominal is often similarly constricted (postpetiole, characteristic of the largest NA subfamily, Myrmicinae, and of Pseudomyrmecinae and most Ecitoninae). The elbowed antennae distinguish ants from other wingless wasps. Ants are usually black, brown, or reddish, and live in colonies with well-defined castes
(typically a worker caste of sterile females and a reproductive caste of winged males and females). +"...virtually all ant keys are for workers only. Since males ... and often queens, can be radically different in appearance from workers, you have to collect the worker stage at the same time as the reproductives." (Eric Eaton
Key to subfamilies & Midwestern genera in(8)
Terminology: ant anatomy diagram
Field guide to NA ants in(3)
; keys to to se. US taxa in(9)
Worldwide and throughout North America, from coastal habitats to the alpine.
Most North American species nest in soil, in leaf litter, or in dead wood, but toward the south, more and more arboreal species occur. All species of Pseudomyrmex are arboreal or stem-inhabiting, as are many Camponotus, Temnothorax, Crematogaster. Some species forage subterraneously, cryptically in litter or wood, while most forage on the ground and low vegetation. Arboreal species usually, and many terrestrial ones, often, forage high in trees, especially in quest of honeydew or extrafloral nectar.
Most ant species forage in warm, humid weather, diurnally in cooler and moister climates, mostly nocturnally in deserts. Ants retreat into the nest from cold or extreme, especially dry, heat. Prenolepis is exceptional in foraging mainly in the cooler months, even on warm days in mid-winter (though apparently not under snow).
Winged reproductive castes are reared in spring or summer. Typically, they fly shortly after reaching adulthood, but in many species of the the formicine genera Camponotus, Prenolepis & Nylanderia, alates overwinter in the parent nest and fly the following spring. Most ant species forage in warm weather, retreating from cold or extreme, especially dry, heat. Prenolepis is exceptional in foraging mainly in the cooler months, even on warm days in winter.
Food varies by genus and species. Most species are to a greater or lesser degree predators or scavengers, and have a sweet-tooth, gathering extrafloral or less often floral nectar, hemipteran honeydew, or fruit juice for their sugar content. Elaisomes of myrmecochorous seeds may provide a significant source of amino acids, monosaccharides and low molecular weight lipids for ants that harvest them. Larvae can eat solid food, while adults have a very narrow oesophagus and feed only on liquids or very small particles such as pollen. Adults often obtain partially digested, liquid food, regurgitated to them by the larvae, and species in the Amblyoponinae feed on haemolymph obtain by chewing of the pleural region of larval abdominal segments! Many Ponerinae, and Cerapachyinae and Ecitoninae, are specialized predators on particular sorts of other arthropods. Species of the myrmicine tribe Attini all cultivate particular strains of fungus, cultivated on compost derived from vegetable matter, cut leaves or the frass of phytophagous insects. Several other myrmicine genera depend largely on the harvesting of seeds gathered, not for their elaiosomes, but for their starchy internal content.
Ants are holometabolous, with the pupa in a cocoon or not, as determined by subfamily, subgenus, or even species. In some, worker pupae are naked or facultatively naked, while sexual pupae are in a cocoon. All living ant species are eusocial
(='truly social'), or are workerless parasites requiring the eusocial medium of a host ant species' colony. Length and number of instars and total period of development various, but in most takes less than a full year. Most genera overwinter brood in the form of relatively uniform-age, partially grown larvae, while a few overwinter mixed age brood, and others carry no brood through winter. In boreal myrmicine species, rearing of sexual brood may take more than one growing season.
Males die shortly after mating, and females tear off their wings after mating, or just before entering a nesting site, and of course remain wingless for the rest of their lives of one to 20+ years, depending on species. Nest-founding queens typically rear the first brood of small (nanitic or minim) workers alone, either sealed in a nest cell and feeding off stored fat and lysing wing musculature (claustrally), or occasionally (semiclaustrally) or regularly foraging for food while rearing the first brood, but almost never after the first workers emerge. In many species, mated queens may join established colonies of their own species. Still others typically invade a colony of a related species and gain the help of the workers of that colony to rear their brood. This may result in a temporary (if the host queen is killed) or less often, permanent mixed-species colony in which the host queen is not killed (inquilinism). In some species, the so-called slave-makers, the host queen is killed, but mixed worker populations are maintained by brood robbing from nests of the appropriate host species. Finally, in Ecitoninae and some others, colonies reproduce by fission. Ecitonines have cyclic, highly synchronized brood development, and associated migratory cycling.
Bert Holldobler, Edward O. Wilson. 1990. Belknap Press.