Paraparatrechina glabra, copyright Erin Prado.

Belongs within: Formicinae.
Contains: Lasius, Nylanderia, Prenolepis.

The Lasiini are a clade of formicine ants united by molecular phylogenetic analysis, as well as the possession of a circular or subcircular propodeal spiracle and widely separated hind coxae.

These ants must be crazy
Published 4 February 2016
Black or longhorn crazy ant Paratrechina longicornis, copyright Efram Goldberg.

I have to admit that my ant-identifying skills are fairly rudimentary. I can recognise some of the more distinctive and/or common varieties—meat ants, bull ants, strobe ants, maybe even green-headed ants—but that’s about as far as it goes. One ant species that I would have a decent chance of recognising right off the bat, however, is the black crazy ant Paratrechina longicornis.

Black crazy ants are an excellent example of what ant experts refer to as ‘tramp species’—generalist species that have spread over a wide range in association with humans. Indeed, the black crazy ant is believed to be the most widespread of all ant species (Wetterer 2008): in tropical regions, it is nigh-on ubiquitous, and in cooler regions it lives within buildings and other warm structures built by humans. So widespread is it, and so readily does it spread, that we can’t say for absolute certain where it originally came from: most likely it originated somewhere in south-east Asia, but other possibilities have been considered over the years.

Black crazy ants belong to the ant subfamily Formicinae; as such, they lack the sting carried by ants of other subfamilies and instead have a nozzle-like pore in its place that they use to spray formic acid at perceived threats. They are distinguished from other ants by their slender appearance, with numerous upright bristles on the body, and long legs and antennae. The antennae are most distinctive, with a particularly long scape (the first antennal segment, before the sharp ‘elbow’). Paratrechina longicornis are known as ‘crazy’ ants because of their erratic mode of foraging, wandering about seemingly aimlessly and not following clear trails. Other ants with similar modes of behaviour have also been dubbed crazy ants, such as the yellow crazy ant Anoplolepis gracilipes, but they are not close relatives.

Effectiveness in numbers: black crazy ants bring down a Florida carpenter ant Camponotus floridanus, from AntWeb.

Black crazy ants may form large or small colonies as circumstances allow; part of the secret of their success is that these colonies can be found in man-made marginal habitats such as on ships at sea. Crazy ant colonies may reach plague proportions; this website relates an account of students at a Florida primary school being so beset by crazy ants that food and other possessions had to be kept in sealed bags on tables at all times with the table legs set in bowls of water to prevent the ants crawling up them. Black crazy ants produced winged reproductives like other ants, but the new queens remove their wings before they expand and emerge from the nest already wingless. While at first glance this seems counter-productive, I can see this behaviour being another factor in their success as a tramp. Colonies living in isolated habitatssuch as the aforementioned ships and buildings in cold climates will tend to persist in that location, rather than losing all their reproductive potential in fruitless exploratory nuptial flights.

In recent times, P. longicornis has been recognised as one of a number of species in the genus Paratrechina (of which it is the effective type). However, a phylogenetic study by LaPolla et al. (2010) of the group of genera to which Paratrechina belongs has found that the genus as then recognised was polyphyletic. Rather than being directly related to other ‘Paratrechnina‘, P. longicornis was most closely related to two south-east Asian genera Euprenolepis and Pseudolasius. This lead to the resurrection of two older generic names, Nylanderia and the cringe-inducingly named Paraparatrechina, into which all Paratrechina species other than P. longicornis were transferred.

Systematics of Lasiini
<==Lasiini [Acanthomyopsini, Prenolepidii]WBF16
    |  i. s.: GlaphyromyrmexWBF16
    |--Cladomyrma Wheeler 1920WBF16, A91
    |    |--C. andrei (Emery 1894) (see below for synonymy)A91
    |    |--C. cryptata Agosti 1991A91
    |    |--C. maschwitzi Agosti 1991A91
    |    |--C. mossyna Agosti 1991A91
    |    `--C. petalae Agosti 1991A91
       |  `--Myrmecocystus Wesm. 1838BS06, B03
       |       |--*M. melligeraB03
       |       |--M. albicansG89
       |       |--M. cursorMS01
       |       |--M. flavicepsBS06
       |       |--M. mimicusES12
       |       |--M. setipes Forel 1894 [=M. viaticus setipes]B03
       |       `--M. viaticusB03
          |  `--+--Pseudolasius Emery 1887 [incl. Nesolasius Wheeler 1935]LBS10
          |     |    |--*P. familiaris (Smith 1861) [=Formica familiaris]Z01
          |     |    |--P. australis Forel 1915TB85
          |     |    |--P. cibdelusZ01
          |     |    |--P. emeryi Forel 1911Z01
          |     |    |--P. risii Forel 1894Z01
          |     |    |--P. similus Zhou 2001Z01
          |     |    `--P. typhlops [=P. (*Nesolasius) typhlops]LBS10
          |     `--+--Euprenolepis Emery 1906 [incl. Chapmanella Wheeler 1930]LBS10
          |        |    |--*E. procera [=Prenolepis (*Euprenolepis) procera]LBS10
          |        |    |--E. negrosensisLBS10
          |        |    |--E. varigataN-ZLI11
          |        |    `--E. witteiN-ZLI11
          |        `--Paratrechina Motschoulsky 1863LBS10, T99
          |             |  i. s.: P. aseta (Forel 1902) [=Prenolepis aseta, Pa. (Nylanderia) aseta]Z01
          |             |         P. opisopthalmos Zhou & Zheng 1998Z01
          |             |--P. longicornis (Latreille 1802)WBF16, FT08 (see below for synonymy)
          |             `--+--P. antsingyWBF16
          |                `--P. zanjensisWBF16
             |  `--Zatania albimaculataWBF16
             `--+--‘Prenolepis’ albimaculataLBS10
                `--Paraparatrechina Donisthorpe 1947WBF16, LBS10
                     |  i. s.: *P. pallida (Donisthorpe 1947)T99 [=Paratrechina (*Paraparatrechina) pallidaLBS10]
                     |         P. albipes [=Paratrechina albipes]LBS10
                     |         P. bufonus [=Pseudolasius bufonus]LBS10
                     |         P. butteli [=Paratrechina butteli]LBS10
                     |           |--P. b. butteliLBS10
                     |           |--P. b. bryanti [=Paratrechina butteli bryanti]LBS10
                     |           `--P. b. malaccana [=Paratrechina butteli malaccana]LBS10
                     |         P. caledonica [=Paratrechina caledonica]LBS10
                     |         P. dichroa [=Paratrechina dichroa]LBS10
                     |         P. emarginata [=Paratrechina emarginata]LBS10
                     |         P. foreli [=Paratrechina foreli]LBS10
                     |           |--P. f. foreliLBS10
                     |           `--P. f. nigriventris [=Paratrechina nigriventris]LBS10
                     |         P. iridescens [=Paratrechina iridescens]LBS10
                     |         P. koningsbergeri [=Paratrechina koningsbergeri]LBS10
                     |         P. lecamopteridis [=Paratrechina lecamopteridis]LBS10
                     |         P. minutula (Forel 1901)LBS10, FT08 (see below for synonymy)
                     |           |--P. m. minutulaLBS10
                     |           `--P. m. buxtoniLBS10
                     |         P. nana (Santschi 1928)LBS10, TB85 [=Paratrechina (Nylanderia) nanaLBS10, TB85]
                     |         P. nettae [=Paratrechina nettae]LBS10
                     |         P. opaca [=Paratrechina opaca]LBS10
                     |           |--P. o. opacaLBS10
                     |           `--P. o. metallescens [=Paratrechina opaca metallescens]LBS10
                     |         P. pusillima [=Paratrechina pusillima]LBS10
                     |         P. sauteri (Forel 1913)LBS10, Z01 (see below for synonymy)
                     |         P. subtilis [=Paratrechina subtilis]LBS10
                     |           |--P. s. subtilisLBS10
                     |           `--P. s. termitophila [=Paratrechina subtilis termitophila]LBS10
                     |         P. tapinomoides [=Paratrechina tapinomoides]LBS10
                     |--P. oceanica [=Paratrechina oceanica]LBS10
                     `--+--P. glabra [=Paratrechina glabra]LBS10
                        `--P. weissi [=Pseudolasius weissi]LBS10

Cladomyrma andrei (Emery 1894) [=Dimorphomyrmex andrei, Aphomomyrmex andrei; incl. A. hewitti Wheeler 1910, *C. hewitti, C. hobbyi Donisthorpe 1937]A91

Paraparatrechina minutula (Forel 1901)LBS10, FT08 [=Prenolepis minutulaTB85, Paratrechina minutulaLBS10, Pr. (Nylanderia) minutulaE14]

Paraparatrechina sauteri (Forel 1913)LBS10, Z01 [=Prenolepis (Nylanderia) minutula r. sauteriZ01, Paratrechina (N.) sauteriLBS10, Z01]

Paratrechina longicornis (Latreille 1802)WBF16, FT08 [=Formica longicornisB03, Prenolepis (Nylanderia) longicornisE14; incl. *Paratrechina currens Motschoulsky 1863T99, Formica gracilescens Nylander 1856Z01, Paratrechina longicornis hagemanni (Forel 1901)LBS10, F. vagans Jerdon 1851Z01]

*Type species of generic name indicated


[A91] Agosti, D. 1991. Revision of the oriental ant genus Cladomyrma, with an outline of the higher classification of the Formicinae (Hymenoptera: Formicidae). Systematic Entomology 16: 293–310.

[B03] Bingham, C. T. 1903. The Fauna of British India, including Ceylon and Burma. Hymenoptera vol. 2. Ants and Cuckoo-Wasps. Taylor and Francis: London.

[BS06] Brady, S. G., T. R. Schultz, B. L. Fisher & P. S. Ward. 2006. Evaluating alternative hypotheses for the early evolution and diversification of ants. Proceedings of the National Academy of Sciences of the USA 103 (48): 18172–18177.

[E14] Emery, C. 1914. Les fourmis de la Nouvelle-Calédonie & des îles Loyalty. In: Sarasin, F., & J. Roux (eds) Nova Caledonia: Forschungen in Neu-Caledonian und auf den Loyalty-Inseln. A. Zoologie vol. 1 pt 4 pp. 393–436, pl. 12. C. W. Kreidels Verlag: Wiesbaden.

[ES12] Espadaler, X., & S. Santamaria. 2012. Ecto- and endoparasitic fungi on ants from the Holarctic region. Psyche 2012: 168478.

[FT08] Framenau, V. W., & M. L. Thomas. 2008. Ants (Hymenoptera: Formicidae) of Christmas Island (Indian Ocean): identification and distribution. Records of the Western Australian Museum 25 (1): 45–85.

[G89] Gestro, R. 1889. Viaggio ab Assab nel Mar Rosso dei signori G. Doria ed O. Beccari con il R. Avviso “Esploratore” dal 16 Novembre 1879 al 26 Febbraio 1880.—IV. Coleotteri. Annali del Museo Civico di Storia Naturale di Genova, Serie 2a, 7: 5–72.

[LBS10] LaPolla, J. S., S. G. Brady & S. O. Shattuck. 2010. Phylogeny and taxonomy of the Prenolepis genus-group of ants (Hymenoptera: Formicidae). Systematic Entomology 35: 118–131.

[MS01] Mocsáry, A., & V. Szépligeti. 1901. Hymenopterák [Hymenopteren]. In: Horváth, G. (ed.) Zichy Jenő Gróf Harmadik Ázsiai Utazása [Dritte Asiatische Forschungsreise des Grafen Eugen Zichy] vol. 2. Zichy Jenő Gróf Harmadik Ázsiai Utazásának Állattani Eredményei [Zoologische Ergebnisse der Dritten Asiatischen Forschungsreise des Grafen Eugen Zichy] pp. 121–169. Victor Hornyánszky: Budapest, and Karl W. Hierseman: Leipzig.

[N-ZLI11] Nur-Zati A. M., G. T. Lim & A. B. Idris. 2011. Checklist of ants of selected hill dipterocarp forests of peninsular Malaysia. Serangga 16 (1): 91–105.

[TB85] Taylor, R. W., & D. R. Brown. 1985. Formicoidea. In: Walton, D. W. (ed.) Zoological Catalogue of Australia vol. 2. Hymenoptera: Formicoidea, Vespoidea and Sphecoidea pp. 1–149. Australian Government Publishing Service: Canberra.

[T99] Terayama, M. 1999. Taxonomic studies of the Japanese Formicidae, part 5. Genus Paratrechina Motschulsky. Memoirs of the Myrmecological Society of Japan 1: 49–64.

[WBF16] Ward, P. S., B. B. Blaimer & B. L. Fisher. 2016. A revised phylogenetic classification of the ant subfamily Formicinae (Hymenoptera: Formicidae), with resurrection of the genera Colobopsis and Dinomyrmex. Zootaxa 4072 (3): 343–357.

Wetterer, J. K. 2008. Worldwide spread of the longhorn crazy ant, Paratrechina longicornis (Hymenoptera: Formicidae). Myrmecological News 11: 137–149.

[Z01] Zhou, S. 2001. Ants of Guangxi. Guangxi Normal University Press: Guilin (China).

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