Subfamily FORMICINAE
Tribe PLAGIOLEPIDINI
Paratrechina longicornis (Latreille, 1802)
"longhorned crazy ant or longlegged crazy ant"

Uploaded 2009; last updated 19 January 2017
Authors: Joe A. MacGown and Ryan J. Whitehouse

Paratrechina longicornis, full face view of a worker(MS, Hancock Co.) (photo by Joe A. MacGown)

Paratrechina longicornis, lateral view of a worker(MS, Hancock Co.) (photo by Joe A. MacGown)

Paratrechina longicornis, dorsal view of a worker(MS, Hancock Co.) (photo by Joe A. MacGown)

Paratrechina longicornis, full face view of a queen (FL, Seminole Co.) (photo by Joe A. MacGown)

Paratrechina longicornis, lateral view of a queen (FL, Seminole Co.) (photo by Joe A. MacGown)

Paratrechina longicornis, dorsal view of a queen (FL, Seminole Co.) (photo by Joe A. MacGown)

Paratrechina longicornis, lateral view of a
worker(MS, Jackson Co.) (photo by Joe A.
MacGown)

Introduction
The genus Paratrechina genus is only represented by six species worldwide, of which only one, Paratrechina longicornis, has been reported from the US. Most Paratrechina species seem to be focused around tropical Africa and Madagascar, but may be also found around the world’s tropical and semitropical areas. These ants are opportunistic foragers and can often be found invading homes in search of sugary food. In nature Paratrechina species are often found tending honeydew producing Hemiptera or drinking from plant nectaries.

Paratrechina species can be identified by having a waist with one distinct segment; acidopore at the apex of the gaster with a circular fringe of setae; 12-segmented antennae; triangular mandibles with five teeth; six-segmented maxillary palps; head and body with dorsally erect, coarse setae; very long antennal scapes and legs; and weakly shining integument with sparse pubescence.

Paratrechina longicornis (Latreille), (Formicinae) the long legged crazy ant, is a small, elongate, long-legged, dark brown ant thought to be native to either Africa or Asia. This pantropical species is the only member of the genus found in North American where it is an ocassional nuisance pest. It is believed to have first entered the United States through Florida and has now spread across the Gulf Coast and southeastern coastal states.

Taxonomic History (Bolton 2016)
Formica longicornis Latreille, 1802: 113 (w.) SENEGAL. Afrotropic. Jerdon, 1851: 124 (q.); André, 1881: 60 (m.); Hung, Imai & Kubota, 1972: 1024 (k.); Wheeler & Wheeler, 1986: 336 (l.); Fox, et al. 2007: 3 (l.); LaPolla, Hawkes & Fisher, 2013: 75 (w.). Combination in Prenolepis: Roger, 1863: 10; in Paratrechina (Nylanderia): Emery, 1910: 129; in Paratrechina: Wheeler, 1921: 112. Senior synonym of Paratrechina currens: Emery, 1892: 166; of Paratrechinagracilescens: Roger, 1863: 10; of Paratrechina vagans: Dalla Torre, 1893}: 179. Senior synonym of Paratrechina hagemanni: LaPolla, Brady & Shattuck, 2010: 128. See also: Mayr, 1865: 50; Forel, 1891: 81; Forel, 1894: 406; Emery, 1910: 129; Trager, 1984: 153; LaPolla, Hawkes & Fisher, 2013.

Diagnosis
Workers of Paratrechina longicornis can be recognized by their dark brown color, shiny integument, small slender body, numerous long erect white setae on the head and body, large eyes, presence of three minute ocelli, exceedingly long antennae and legs, single petiole, and acidopore at gastral apex. This species differs from related Nylanderia species by the proportionally longer antennae and legs.

Identification
Worker: Small (HL 0.67–0.72 mm, HW 0.49–0.51 mm, SL 1.16–1.19 mm, EL 0.19–0.21 mm, MeSL 0.95–1.06 mm) (n=5) (n=5) (MEM specimens). Head and body dark brown with irridescent blueish reflections; antennae, coxae, femora, and tibia slighter lighter brown; and tarsi pale yellow brown to light brown. Head longer than wide, ovoid; with faint reticulate sculpture; numerous elongate, coarse, white macrochaetae present, especially posteriorly and along edges of head; eyes large, length about 1/3 the length of the head, distinctly convex, located at about the midpoint of head; three minute ocelli present (difficult to see at low magnification); antennae 12-segmented, elongate, lacking club, lacking erect macrochaetae; scape elongate, about twice as long as head length; clypeus convex, anterior border rounded, notched medially; mandibles somewhat sickle-shaped in frontal view, parallel sided in lateral view, with five teeth near apex; maxillary palps long, six-segmented. Mesosoma slender, somewhat flattened dorsally, shiny, with light shagreening, with several, coarse, erect white setae present on promesonotum, and sparse, appressed, hair-like setae; propodeum broadly rounded in lateral view. Legs very long, hind femur length about equal to mesosomal length, femora and tibia with scattered erect setae. Waist single segmented; petiolar node relatively short with a flat anterior face and an anteriorly sloped posterior face. Gaster shiny, with light shagreening, numerous elongate, coarse, white macrochaetae present; small acidopore present at apex.

Queen: Average sized, about twice the size of workers (HL 1.06 mm, HW 1.03 mm, SL 1.40 mm, EL 0.39 mm, MeSL 1.92 mm) (n=1) (MEM specimen). Head and body dark brown; fore coxae, femora, and tibia brown; antennae, mid and hind coxae, trochanters, and tarsi yellowish brown. Head about  as long as wide, squarish; finely shagreened beneath dense, short, appressed, fine, pubescence; longer, erect setae absent; eyes large,  about 1/3 the length of the head, located near midline of the head; three ocelli present; antennae 12-segmented, elongate, lacking club, lacking erect macrochaetae; scape elongate, about 1.5 times head length; clypeus convex, anterior border  broadly rounded, shallowly notched medially; mandibles triangular, with five distinct teeth; maxillary palps long. six-segmented. Mesosoma robust, lightly shagreened beneath dense, short, appressed, fine, pubescence; longer erect setae absent; pronotum rectangular in lateral view; propodeum lacking spines, declivity gently sloped. Wings with dusky yellow brown tint; forewing with closed costal, basal, and marginal cells. Waist single segmented; petiolar node short in comparison to the gaster and often obscured by the anterior edge of the gaster in the dorsal view. Gaster covered in dense pubescence; lacking sting; acidopore present at apex.

Male: (No specimens in MEM; description based on antwiki.org pictures). Head, antennal scapes, femora, and tibia brown; mesosoma, waist, petiole, funiculi, coxae, and tarsi yellowish brown; gaster dark brown; legs, especially joints, lighter colored than the body. Head about as long as wide, spherical; weakly shining with very feint reticulation; sparse, short, hair-like setae present, especially anterior to eyes; a few coarse, long, erect macrochaetae present; eyes distinctly convex, large, about 1/3 the length of the head, located at the midpoint of the head; three ocelli present; antennae 13-segmented, elongate, lacking club, scape elongate; clypeus broadly rounded, anterior border straight to very slightly concave; mandibles reduced; maxillary palps long and six-segmented. Mesosoma mostly glabrous and shining with some coarse, erect setae; dorsum smoothly curved from mesoscutum to base of propodeum. Wings with light grayish brown tint; forewing forewing with closed costal, basal, and marginal cells. Waist single segmented; petiolar node triangular from lateral view. Gaster shining, mostly glabrous except for a few scattered, appressed fine setae; numerous long, erect setae present, especially at sclerite margins and apically; genitalia present at apex, parameres somewhat squared in ventral view, penivalva extend beyond volsella.

Biology
Paratrechina longicornis is found in tropical and semi tropical habitats worldwide where it is closely associated with human habitation. Its ability to inhabit disturbed environments and live along side humans is a primary reason for its widespread range. Additionally, P. longicornis has been able to expand its range into non tropical environments by inhabiting heated buildings. Outdoor nests can be found in mulch, rotten wood, tree cavities, or under other objects found on the ground. This species produces super colonies, which may be huge, with multiple queens. These ants are general scavengers and are attracted to sugary foods and baits, and this species is known to tend honeydew producing Hemipterans. In the Southeastern United States P. longicornis has been collected from September to April and is one of the most commonly found ants in the winter months (in heated buildings).
In Mississippi, outdoor populations of this species are now well established in all three coastal counties.

Pest Status
Paratrechina longicornis is considered to be a nuisance pest species due to its tendency to forage and nest in homes and buildings and the ease of which humans move it around. This is adept at locating food sources and will readily feed on common household foods including meat, sweats, vegetables, and fountain soda syrups. Due to huge populations formed from P. longicornis supercolonies, this species may have a negative effect of native species of ants and other arthropods. As with other supercolonial species, control is difficult.

Distribution
Native Range: Asian origin argued by Wetterer (2008) and LaPolla et al. (2013). Looking at sister taxons suggests a possible African woodland origin (antwiki.org).

Australian: Australia, Barrow Island, Cook Islands, Fiji, French Polynesia, Guam, Hawaii, Indonesia, Kiribati, Marshall Islands, Micronesia, New Caledonia, New Guinea, New Zealand, Niue, Norfolk Island, Northern Mariana Islands, Palau, Samoa, Solomon Islands, Timor-Leste, Tokelau, Tonga, Tuvalu, Vanuatu (AntWeb.org).
Ethiopian: Chad, Comoros, Democratic Republic of Congo, Eritrea, Europa Island, Guinea, Kenya, Madagascar, Malawi, Mali, Mauritania, Mauritius, Mayotte, Mozambique, Nigeria, Reunion, Saint Helena, Senegal, Seychelles, South Africa, Sudan, Tanzania, Uganda, United Arab Emirates, Yemen (AntWeb.org).
Nearctic: Baja California, United States (AntWeb.org and MEM).
Neotropical:  Anguilla, Aruba, Bahamas, Barbados, Belize, Bermuda, Brazil, British Virgin Islands, Cayman Islands, Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, French Guiana, Galapagos Islands, Guatemala, Guyana, Haiti, Honduras, Jamaica, Martinique, Mexico, Nicaragua, Panama, Paraguay, Peru, Puerto Rico, Saint Kitts and Nevis, Saint Lucia, Trinidad and Tobago, Turks and Caicos Islands, Venezuela (AntWeb.org).
Oriental: Bangladesh, Borneo, Cambodia, Christmas Island, India, Krakatau Islands,
Malaysia, Nepal, Nicobar Island, Pakistan, Philippines, Singapore, Sri Lanka, Taiwan, Thailand, Vietnam (AntWeb.org).
Palearctic: Bahrain, Balearic Islands, Belgium, China, Estonia, France, Iran, Israel, Japan, Libya, Macaronesia, Malta, Saudi Arabia, Spain, United Kingdom of Great Britain and Northern Ireland (AntWeb.org).

U.S. Distribution: AL, AZ, CA, FL, GA, HI, LA, MS, NC, SC, TX (AntWeb.org and MEM).
Southeastern U.S. Distribution: AL, FL, GA, LA, MS (Hancock, Harrison, and Jackson Cos.), NC, SC (AntWeb.org and MEM).

Acknowledgments
Funding for the ant work being done by the MEM in Alabama and Mississippi is from several sources including the National Institute of Food and Agriculture, United States Department of Agriculture, under Project No. MIS-012040, the Mississippi Agricultural and Forestry Experiment Station at Mississippi State University, with support from State Project MIS-311080, NSF Grants BSR-9024810 and DFB-9200856, the Tombigbee National Forest (U.S. Forest Service), the Noxubee Wildlife Refuge, Mississippi Natural Heritage Program Research Grant, USDA Forest Service Agreement No. 08-99-07-CCS-010, the William H. Cross Expedition Fund, and primarily by the USDA-ARS Areawide Management of Imported Fire Ant Project (2001-2014) and USDA-ARS Areawide Management Invasive Ants Project. Additionally, special cooperation has been provided by State Parks, National Forests, National Wildlife Refuges, the Natchez Trace Parkway, and from various private landowners in both Alabama and Mississippi.

Literature Cited
André, Ern. 1881. Catalogue raisonné des Formicides provenant du voyage en Orient de M. Abeille de Perrin et description des espèces nouvelles. Annales de la Société Entomologique de France (6)1:53-78.

Bolton, B. 2016.  Bolton World Catalog Ants. Available online: http://www.antweb.org/world.jsp. Accessed 9 March 2016.

Dalla Torre, K. W. 1893. Catalogus Hymenopterorum hucusque descriptorum systematicus et synonymicus. Vol. 7. Formicidae (Heterogyna).

Emery, C. 1892 ("1891"). Note sinonimiche sulle formiche. Bullettino della Società Entomologica Italiana 23:159-167.

Emery, C. 1910. Beiträge zur Monographie der Formiciden des paläarktischen Faunengebietes. (Hym.) Teil X. Deutsche Entomologische Zeitschrift 1910:127-132.

Forel, A. 1891. Les Formicides. [part]. In: Grandidier, A. 1891. Histoire physique, naturelle, et politique de Madagascar. Volume XX. Histoire naturelle des Hyménoptères. Deuxième partie (28e fascicule). Paris: Hachette et Cie, v + 237 pp.

Forel, A. 1894. Les Formicides de l'Empire des Indes et de Ceylan. Part IV. Journal of the Bombay Natural History Society 8:396-420.

Fox, E.G.P.; Solis, D.R.; Jesus, C.M.; Bueno, O.C.; Yabuki, A.T.; Rossi, M.L. 2007. On the immature stages of the crazy ant Paratrechina longicornis (Latreille 1802) (Hymenoptera: Formicidae). Zootaxa 1503: 1-11.

Hung, A. C. F.; Imai, H. T.; Kubota, M. 1972. The chromosomes of nine ant species (Hymenoptera: Formicidae) from Taiwan, Republic of China. Annals of the Entomological Society of America 65:1023-1025.

Jerdon, T. C. 1851. A catalogue of the species of ants found in Southern India. Madras Journal of Literature and Science 17:103-127.

LaPolla, J. S.; Brady, S. G.; Shattuck, S. O. 2010. Phylogeny and taxonomy of the Prenolepis genus-group of ants (Hymenoptera: Formicidae). Systematic Entomology 35:118-131.

LaPolla, J. S.; Hawkes, P. G.; Fisher, J. N. 2013. Taxonomic review of the ant genus Paratrechina, with a description of a new species from Africa. Journal of Hymenoptera Research 35:71-82.

Latreille, P. A. 1802. Histoire naturelle des fourmis, et recueil de mémoires et d'observations sur les abeilles, les araignées, les faucheurs, et autres insectes. Paris: Impr. Crapelet (chez T. Barrois), xvi + 445 pp.

Mayr, G. 1865. Formicidae. In: Novara Expedition 1865. Reise der Österreichischen Fregatte "Novara" um die Erde in den Jahren 1857, 1858, 1859. Zoologischer Theil. Bd. II. Abt. 1. Wien: K. Gerold's Sohn, 119 pp.

Roger, J. 1863. Verzeichniss der Formiciden-Gattungen und Arten. Berliner Entomologische Zeitschrift 7(Beilage):1-65.

Smith, M. R. 1965. House-infesting ants of the Eastern United States, their recognition, biology, and economic importance. United States Department of Agriculture, Technical Bulletin No. 1326: i-105.

Trager, J. C. 1984. A revision of the genus Paratrechina (Hymenoptera: Formicidae) of the continental United States. Sociobiology 9:49-162.
Wetterer, J.K. 2008. Worldwide spread of the longhorn crazy ant, Paratrechina longicornis (Hymenoptera: Formicidae). Myrmecoloigcal News 11, 137-149.

Wheeler, W. M. 1921. Chinese ants collected by Prof. C. W. Howard. Psyche (Cambridge) 28:110-115.

Wheeler, G. C.; Wheeler, J. 1986. Supplementary studies on ant larvae: Formicinae (Hymenoptera: Formicidae). Journal of the New York Entomological Society 94:331-341. 

Links

AntWeb
AntCat
AntWiki