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Genus Pheidole - Big-headed Ants

Big-Headed Ant - Pheidole Pheidole Red wasp-ant - Pheidole - male Pheidole pilifera Ant 9 - Pheidole P. crassicornis? - major worker - Pheidole crassicornis - female Small orange-brown Ant with slender gaster, no major spikes, and a weird saddle ... - Pheidole Pheidole crassicornis - Pheidole dentigula
Classification
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)
Subfamily Myrmicinae
Tribe Attini ("Higher" myrmicines - no group name)
Genus Pheidole (Big-headed Ants)
Synonyms and other taxonomic changes
formerly in Pheidolini
Explanation of Names
Greek pheid- 'sparing', 'thrifty'(1), or more exactly pheidole 'thriftiness', 'grudging use'
Numbers
74 described spp. in our area(2) and >1000 worldwide + perhaps that many or more undescribed; the most abundant and diverse ants of the New World(3)
Species are relatively few in northern states, more diverse in the Southeast, and especially rich in the desert Southwest.
Size
minors 1.5-4 mm, majors 2-5 mm, supermajors of P. rhea 8 mm
Identification
Nearly indistinguishable from small Aphaenogaster workers, but the latter never have big-headed majors, and none are as small as most Pheidole.
Range
cosmopolitan, but particularly diverse in the tropics(4); in the New World, n. US to Argentina(3)
Food
Some species are seed harvesters(4), many are generalist predators/scavengers
Remarks
This is probably the largest genus of ants in the world, possibly rivaled only by Camponotus, both with an unknown number, but easily over 1000 species. They have pronounced worker caste dimorphism, especially in seed harvesting species; major workers are larger than minors and have disproportionately large heads. A few species have an even larger supermajor caste, and are thus trimorphic. Scavenger predators are usually less strongly dimorphic, and longer legged than the seed harvesters.
Internet References
Works Cited
1.Dictionary of Word Roots and Combining Forms
Donald J. Borror. 1960. Mayfield Publishing Company.
2.American Insects: A Handbook of the Insects of America North of Mexico
Ross H. Arnett. 2000. CRC Press.
3.Pheidole in the New World: A dominant, hyperdiverse ant genus
Wilson E.O. 2003. Harvard University Press. 818 pp.
4.Wild A. (-2014) Myrmecos