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Family Formicidae - Ants

Carpenter Ants? - Formica obscuripes - female Phaidole? - Pheidole - female Ant - Solenopsis C. modoc attacking trespassing C. laevigatus queen - Camponotus modoc Ant or termite? - Camponotus Carpenter Ant_Male - Camponotus Unknown ant - Camponotus - female Eastern Black Carpenter Ant?
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
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), also see(2)(3)(4)
Explanation of Names
Latin formica ant(5)
ant goes back to Old English aemete, aemette(5) -- 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(5); an archaic Modern English variant: emmet
over 700 spp. in 80 genera in our area(6)(7); 14,000 spp. in ~300 genera of 20+ subfamilies(8); faunal checklists for many US states provided on(9), QC checklist here(10)
Overview of our faunaTaxa not yet in the guide are marked (*) and linked to AntWeb pages(6)
Subfamily Amblyoponinae
Subfamily Dorylinae(2)
Subfamily Dolichoderinae
Subfamily Ectatomminae
Subfamily Formicinae
Tribe Plagiolepidini *Acropyga
Subfamily Myrmicinae(3)
Subfamily Ponerinae(4)
Subfamily Proceratiinae
Subfamily Pseudomyrmecinae
1-25 mm
Primitively, antennomere and palp segment counts are typical for Aculeata, antennae 12-segmented (13 in males), palp formula 6,4.
These are variously reduced among different genera, with some ants having as few as 6 antennomeres and palp formula 1, 1. Such reductions are most common in ants with strictly subterranean or cryptic biology.
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(11)
Terminology: ant anatomy diagram

Guides: NA(6); New England(12) (good for most of the e. NA); se. US(13)
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 winter.
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.
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, lycaenid larval exudates, 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, Pogonomyrmex, Veromessor and some Pheidole, especially in arid regions, depend largely on the harvesting of seeds gathered, not for their elaiosomes, but for their starchy internal content.
Life Cycle
Ants are holometabolous, with the pupa in a cocoon or not, as determined by subfamily, genus, 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 nearly daily migration to new temporary nest sites ("bivouacs") when growing larvae are present.
Non-native Ants in the guide (as of 2/23/2014)
No common name Anergates atratulus. From the Old World
No common name Brachymyrmex obscurior. From Central and South America
No common name Brachymyrmex patagonicus. From South America
Chinese Needle Ant, Brachyoponera chinensis. From Asia
Compact Carpenter Ant, Camponotus planatus. From the Neotropics, 1910
No common name, Hypoponera opaciceps. From Brazil
No common name, Lasius emarginatus. From Mediterranean and Central Europe. Very recent
(Common) Black Ant, Lasius niger. From Eurasia
Argentine Ant, Linepithema humile. From S America
No common name, Monomorium pharaonis. Probably from Africa
European Fire Ant, Myrmica rubra. From Europe, 1908
No common name, Nylanderia flavipes. From Japan
Tawny Crazy Ant, Nylanderia fulva. From the Neotropics, 2002
Caribbean Crazy Ant, Nylanderia pubens. From West Indies, 1953
Rough-node Snapping Ant, Odontomachus ruginodis. From West Indies, 1930s
Longhorn Crazy Ant, Paratrechina longicornis. From Old World tropics, early 1900s
Bigheaded Ant, Pheidole megacephala. Native to Mauritius, spread worldwide. 1933
No common name, Pheidole moerens. From Greater Antilles?
No common name, Platythyrea punctata(?). From Central and South America
Elongate Twig Ant, Pseudomyrmex gracilis. From Mexico. Florida 1960
Pan-tropical Panther Ant, Pseudoponera stigma, Probably introduced
Red Imported Fire Ant, Solenopsis invicta. From S. America, 1930s or 1940s
Black Imported Fire Ant, Solenopsis richteri. From S. America, around 1918
No common name, Strumigenys membranifera. From the Old World tropics
Ghost Ant, Tapinoma melanocephalum. From the Old World tropics, 1930
Tramp Ant, Tetramorium bicarinatum. From the from Africa, 1800s
White-Footed Ant, Technomyrmex difficilis. From the Palaearctic, 1986
Pavement Ant, Tetramorium species-e. From Europe
Japanese Pavement Ant, Tetramorium tsushimae. From Japan, early 1900s
Little Fire Ant, Wasmannia auropunctata. From the Neotropics, 1920s
Print References
Internet References
Ants of Washington, DC area (a list of 131 spp.)