Subfamily PONERINAE
Tribe PONERINI

Pachycondyla chinensis (Emery) 1895
"Asian needle ant"

By Joe A. MacGown, updated 25 November 2013

Pachycondyla chinensis, full face view of worker
Pachycondyla chinensis, profile view of worker
Pachycondyla chinensis, full face view of worker (Photo by Joe A. MacGown)
Pachycondyla chinensis, profile view of worker (Photo by Joe A. MacGown)
Pachycondyla chinensis, profile view of an alate queen
Pachycondyla chinensis, profile view of an alate queen (Photo by Joe A. MacGown)
Pachycondyla chinensis, profile view of an alate queen (Photo by Joe A. MacGown)

Introduction
Of the more than 200 Pachycondyla species known worldwide (Bolton, 1995), only four, which are all introduced, have been reported from the U.S. Pachycondyla chinensis, the Asian needle ant, was first detected in the United States in Dekalb County, Georgia in approximately 1932 (Smith, 1934). This species is an average sized, dark brownish-black ant with a conspicuous stinger. It is considered an invasive species that establishes large populations that may displace native species. Reactions in humans from the sting of this exotic species range from mild to severe, sometimes with long lasting symptoms (Nelder et al, 2006). Consequently, P. chinensis poses an emerging health threat throughout its range, as well as areas to where it may be spreading. However, it is not overly aggressive. Stings typically result from handling workers or by winged queens landing on individuals and becoming trapped between clothing layers and skin.

Taxonomic History (provided by Barry Bolton, 2013)
Described as Ponera nigrita subsp. chinensis Emery (1895). Combination in Euponera (Brachyponera), Emery (1909); in Brachyponera, Brown (1958); in Pachycondyla, in Bolton (1995); junior synonym of Pachycondyla solitaria Smith (1874) [Junior primary homonym of Pachycondyla solitaria Smith, 1860] and hence first available replacement name (Brown, 1958).

Identification
Pachycondyla chinensis is a an average sized species with workers usually less than 5.0 mm in total length and queens up to 6.5 mm in total length. The color of both workers and queens is dark brown, with the legs, mandibles, and outer antennal segments being lighter orangish-brown. Workers of this species can be distinguished by their smooth and shiny mesopleural region; the propodeum being strongly depressed below the mesonotum; and by the large eyes with many facets. The only similar sized species in the U.S., P. stigma, differs in that the mesopleura is finely punctulate; the propodeum is not strongly depressed; and the eyes are much smaller, only having a few facets.

Biology and Economic Importance
Pachycondyla chinensis, commonly called the Asian needle ant (in the past this species has also been called the Chinese needle ant), typically nests in soil in somewhat damp areas, especially below stones, in rotting logs and stumps, or other debris. In urban settings it may also be found under mulch, railroad ties, bricks and pavers. Colony size ranges from less than 100 individuals to several thousand, and multiple queens may be present. Unlike many introduced, invasive ant species, it can nest in natural wooded habitats. This species appears to prefer termites as a food source.

The Asian needle ant has been shown to negatively impact biodiversity and poses medical risks for humans from anaphalaxis as a result of stings (Nelder et al. 2006). Although this species possesses a large sting, it is not an aggressive stinger. Typically, stings are a result of an individual disturbing a colony or having a winged female land on the body and become trapped between the skin and clothing layer. Stings are painful and persist for up to 30 minutes or more. I have been stung by this species and can attest to the veracity of the sting of this species.

Distribution
This introduced species is thought to have been introduced from Japan.

US Distribution: Alabama (MEM record), Mississippi (MEM record), Connecticut, Florida (old record), Georgia, South Carolina, New York, North Carolina, Tennessee, Virginia, Washington, and Wisconsin (MEM records; Dunn and Menninger 2013, Guenard, 2009; Guénard and Dunn 2010, MacGown 2009; Nelder et al, 2006).

Literature Cited
Bolton, B. 1995. A new general catalogue of the ants of the world. Harvard University Press: Cambridge, Massachusetts, USA.

Bolton, B. 2013.  Bolton World Catalog Ants. Available online: http://www.antweb.org/world.jsp. Accessed 25 November 2013.

Dunn, R. and H. Menninger. 2013. Amateur scientists discover Asian needle ant has expanded its range by thousands of miles. [Online]. Available: http://www.yourwildlife.org/2012/08/amateur-scientists-discover-asian-needle-ant-has-expanded-its-range-by-thousands-of-miles-unnoticed/ (Accessed September 5, 2013).

Emery, C. 1895. Viaggio di Leonardo Fea in Birmania e regioni vicine. LXIII. Formiche di Birmania del Tenasserim e dei Monti Carin raccolte da L. Fea. Parte II. Annali del Museo Civico di Storia Naturale 34[=(2)14]: 450-483. 

Emery, C. 1909. Beiträge zur Monographie der Formiciden des paläarktischen Faunengebietes. (Hym.) Teil VIII. Deutsche Entomologische Zeitschrift 1909: 355-376.

Guenard, B. 2009. Pachycondyla chinensis, the Asian Needle Ant. Available online at: http://www4.ncsu.edu/~bsguenar/Pachycondyla%20chinensis%20page.html. Accessed 26 March, 2009.

Guénard B., and R. R. Dunn. 2010. A New (Old), Invasive ant in the hardwood forests of eastern North America and its potentially widespread impacts. PLoS ONE 5(7): e11614. doi:10.1371/journal.pone.0011614.

MacGown, J. A. 2009. The Asian needle ant, Pachycondyla chinensis Emery (Hymenoptera: Formicidae), reported from Alabama (online: http://midsouthentomologist.org.msstate.edu/Volume2/Vol2_2_html_files/vol2-2_003.html). Midsouth Entomologist 2 (2) 88-89.

Nelder, M. P., E. S. Paysen, P. A. Zungoli, and E. P. Benson. 2006. Emergence of the introduced ant Pachycondyla chinensis (Formicidae: Ponerinae) as a public health threat in the southeastern United States.

Smith, F. 1874. Descriptions of new species of Tenthredinidae, Ichneumonidae, Chrysididae, Formicidae, &c. of Japan. Transactions of the Entomological Society of London 1874: 373-409.

Smith, F. 1860. Catalogue of hymenopterous insects collected by Mr. A. R. Wallace in the islands of Bachian, Kaisaa, Amboyna, Gilolo, and at Dory in New Guinea. Journal and Proceedings of the Linnean Society of London. Zoology 5(17b) (suppl. to vol. 4): 93-143. 

Smith, M. R. 1934. Ponerine ants of the genus Euponera in the United States. Ann. Entomol. Soc. Am. 27: 558-56.

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Pachycondyla chinensis, the Asian Needle Ant - by Benoit Guenard