Paratrechina longicornis

This ant has been transported to almost all the populated subtropical and tropical areas in the world. It is usually in disturbed areas but can invade undisturbed areas as well. It is a general scavenger and also tends honeydew-producing Homoptera. Nests are in accumulations of dry litter or mulch or under objects on the ground.



Distribution
Introduced into Florida and found as far north and west as Leon County, but much commoner in south Florida. Pest status: a minor nuisance in outdoor eating areas, and frequently enters buildings where there is easy access to the outside. First published Florida record: Smith 1930. (Deyrup, Davis & Cover, 2000.)

Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Chad, Comoros, Democratic Republic of Congo, Eritrea, Gambia, Guinea, Kenya, Malawi, Mali, Mauritania, Mozambique, Saint Helena, Senegal, Socotra Archipelago, Uganda, United Arab Emirates, United Republic of Tanzania, Yemen. Australasian Region: Australia, New Caledonia, Norfolk Island. Indo-Australian Region: Borneo, Cook Islands, Fiji, Guam, Hawaii, Indonesia, Kiribati, Krakatau Islands, Malaysia, Marshall Islands, Micronesia (Federated States of), New Guinea, Niue, Northern Mariana Islands, Palau, Philippines, Samoa, Singapore, Solomon Islands, Timor-Leste, Tokelau, Tonga, Tuvalu, Vanuatu. Malagasy Region: Madagascar, Mauritius, Mayotte, Réunion, Seychelles. Nearctic Region: United States. Neotropical Region: Anguilla, Aruba, Bahamas, Barbados, Belize, Bermuda, Brazil, Cayman Islands, Chile, Colombia, Costa Rica, Dominican Republic, Ecuador, French Guiana, Galapagos Islands, Greater Antilles, Grenada, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Lesser Antilles, Mexico, Netherlands Antilles, Nicaragua, Panama, Paraguay, Peru, Puerto Rico, Saint Kitts and Nevis, Saint Lucia, Trinidad and Tobago, Turks and Caicos Islands, Venezuela. Oriental Region: Bangladesh, Cambodia, India, Laos, Nepal, Nicobar Island, Pakistan, Sri Lanka, Thailand, Vietnam. Palaearctic Region: Bahrain, Balearic Islands, Belgium, Canary Islands, China, Estonia, France, Iberian Peninsula, Iran, Israel, Japan, Libya, Malta, Oman, Spain, United Kingdom of Great Britain and Northern Ireland.

Biology
Sharaf et al. (2017) report on this species in Yemen: The known habitats of this species are diverse, no doubt enabling its wide distribution. We observed Paratrechina longicornis nesting in moist soil under a rock adjacent to a date palm tree. Another nest was collected from dry soil under shrub Frangula alnus Mill. (Rhamnaceae). Many workers were found in leaf litter under a date palm tree where the soil was moist and rich in accumulated sheep and goat faeces. Several workers were foraging in leaf litter on dry soil under an Eragrostis tef (Zucc.) Trotter (Poaceae) tree, where the soil was dry. A nest was observed under a rock in moist, compacted, clay soil. Hundreds of workers were foraging in moist leaf litter and on twigs of a small shrub. Several workers were nesting under a stone in humid soil and next to banana plantations. A nest was found under a rock next to a dragon blood tree, Dracaena cinnabari Balf.f. (Asparagaceae). This species has been reported as a pest in greenhouses in both temperate and tropical regions (Nylander 1856; Motschoulsky 1863).

Bertelsmeier et al. (2015) examined elements of interspecific aggression between this species and several other highly invasive ants. In laboratory assays Paratrechina longicornis was adept at avoiding aggressive interactions. When confronted by workers of other invasive ant species P. longicornis either acted indifferently or moved away.

Chemical Ecology
LeBrun et al. (2015) found a behaviour, first noted and resulting from interactions between Solenopsis invicta and Nylanderia fulva, that detoxifies fire ant venom is expressed widely across ants in the subfamily Formicinae. This behavior was also studied and shown in experiments with P. longicornis. See the biology section of the N. fulva page for a description of acidopore grooming and the use of formic acid for detoxification of a specific class of venoms that are produced by ants that may interact with formicines in the context of predation and food competition.

Male
Additional images can be found here.

Nomenclature

 *  longicornis. Formica longicornis Latreille, 1802c: 113 (w.) SENEGAL. Jerdon, 1851: 124 (q.); André, 1881b: 60 (m.); Hung, Imai & Kubota, 1972: 1024 (k.); Wheeler, G.C. & Wheeler, J. 1986d: 336 (l.); Fox, et al. 2007: 3 (l.). Combination in Prenolepis: Roger, 1863b: 10; in Pr. (Nylanderia): Emery, 1910a: 129; in Paratrechina: Wheeler, W.M. 1921e: 112. Senior synonym of currens: Emery, 1892b: 166; of gracilescens: Roger, 1863b: 10; of vagans: Dalla Torre, 1893: 179. Senior synonym of hagemanni: LaPolla, Brady & Shattuck, 2010a: 128. See also: Mayr, 1865: 50; Forel, 1891b: 81; Forel, 1894c: 406; Emery, 1910a: 129; Trager, 1984b: 153.
 * vagans. Formica vagans Jerdon, 1851: 124 (w.q.) INDIA. [Unresolved junior primary homonym of Formica vagans Olivier, 1792: 501.] Junior synonym of longicornis: Dalla Torre, 1893: 179; Forel, 1894c: 408.
 * gracilescens. Formica gracilescens Nylander, 1856a: xxviii (w.) FRANCE. [Also described as new by Nylander, 1856b: 73.] Junior synonym of longicornis: Roger, 1863b: 10.
 * currens. Paratrechina currens Motschoulsky, 1863: 14 (w.) SRI LANKA. Junior synonym of longicornis: Emery, 1892b: 166. Neotype designated: LaPolla, Brady & Shattuck, 2010b: 1.
 * hagemanni. Prenolepis longicornis var. hagemanni Forel, 1901h: 65 (w.) DEMOCRATIC REPUBLIC OF CONGO. Combination in Paratrechina: Emery, 1925b: 217. Junior synonym of longicornis: Wheeler, W.M. 1922a: 942. Revived from synonymy: Emery, 1925b: 217. Junior synonym of longicornis: LaPolla, Brady & Shattuck, 2010a: 128.

Worker
LaPolla et al. (2013) - Measurements in millimeters (n=4): TL: 2.1- 2.5; HW: 0.46-56; HL: 0.49-0.7; EL: 0.17-0.23; SL: 0.98-1.16; PW: 0.34-0.43; WL: 0.82-0.98; PrFL: 0.6-0.9; GL: 0.83-0.9. Indices: CI: 73-94; REL2: 38-42 ; SI: 182-226.

Overall coloration pale to very dark brown, often with a distinct blueish iridescent sheen, especially on the mesosoma and gaster. Mandibles, antennae and legs (especially the trochanters of all legs, which are a strongly contrasting very pale yellow-brown) much lighter in color; cuticle smooth and moderately shining with faint shagreenate sculpture, which is most obvious on head and gaster. Head narrow, distinctly longer than broad, with abundant pale (yellow-brown to almost white), erect macrosetae; anterior clypeal margin with a shallow medial indentation; scapes with a dense layer of very fine pubescence but lacking erect macrosetae; eyes large and convex, extending beyond head lateral margin in full frontal view; posterior head margin with rounded posterolateral corners; three distinct ocelli present. Mesosoma with scattered pale erect macrosetae (PSC = 3; MSC = 3-4); in profile pronotum and mesonotum almost flat dorsally, with a broadly angled junction; metanotal area relatively indistinct, medially about 1/5 the length of the mesonotum but longer laterally than medially; dorsum of propodeum almost flat to very shallowly domed, rounding evenly into the short declivitious face; anterolateral portion of dorsal face with some scattered pubescence. Gaster with abundant erect pale macrosetae.