Subfamily PONERINAE
Tribe PONERINI
Brachyponera chinensis (Emery) 1895 [=Pachycondyla chinensis]
"Asian needle ant"

By Joe A. MacGown, updated 23 March 2016

Introduction
Brachyponera has more than 20 species in its genus, but only one that is present in the southeastern United States at present. Most species are found in Africa, Asia, and Australia with the highest species diversity in Southeast Asia.

Brachyponera chinensis Emery(Ponerinae), the Asian needle ant, is small, brownish black stinging species native to Japan. It was first detected in the United States in Dekalb County, Georgia in approximately 1932 (Smith, 1934). Since then, populations have spread throughout large areas along the east coast and into other regions. It is considered an invasive species that stings humans and may displace native species. Most recent literature gives refers to this species as Pachycondyla chinensis; however, Schmidt and Shattuck (2014) revived it from synonymy. 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, B. 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 alate queens landing on individuals and becoming trapped between clothing layers and skin.

Common Name
Asian needle ant.

Taxonomic History (Bolton 2016)
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). Brachyponera revived from synonymy: Schmidt and Shattuck, 2014.

Identification
Worker:TL ≈ 4.0-5.0mm, HL 1.04-1.09mm, HW 0.91-0.96mm, SL 0.97-0.99mm, EL 0.17-0.19mm, MeSL 1.44-1.48mm (n=5) (MEM specimens). Average sized dark brown to black ant with outer antennae segments, mandibles, and legs a lighter orangish-brown with the workers usually less than 5.00mm in total length. Head longer than wide with dense, appressed setae on the head, mandibles, and scape and a few erect setae; eyes small and located on the anterior 1/4 of the head; mandibles large and triangular with eight to ten teeth of various sizes; clypeus shining with a few long, anteriorly directed, erect setae; prominent frontal lobes covering the antennal insertion point; antennae 12-segmented. Mesosoma with a smooth and shiny mesopleural region while the rest of the mesosoma has dense appressed setae and some erect setae; propodeum strongly depressed below the mesonotum; hind tibia with two spurs, a large, pectinate one and a simple small one. Waist is single-segmented; subpetiolar process with a distinct, acutely angled projection with some erect setae. Gaster elongate and cylindrical with dense, appressed and erect setae; anterior face almost entirely vertical; prominent sting present at apex.

Queen: TL ≈ 5.0-6.5mm, HL 1.10-1.12mm, HW 0.94-0.99mm, SL 0.98-1.00mm, EL 0.29-0.30mm, MeSL 1.58-1.72mm (n=5) (MEM specimens). Dark brown to black ant with outer antennae segments, mandibles and legs being a lighter orangish-brown. Can be up to 6.50mm in length. Head longer than wide and covered with dense, appressed setae as well as the antennal scapes and with erect setae on the mandibles and the ventral surface; eyes ovoid with the posterior edge at the midline of the head; three ocelli present; mandibles well developed and triangular; frontal lobes prominent and covering the antennal insertion point; antennae are 12-segmented. Mesosoma with a mixture of appressed and erect setae and a glabrous, smooth, shining mesopleural region; enlarged with four wings or wing scars; hind tibia with two spurs, a large, pectinate one and a simple small one; posterior edge with a smooth and shining glabrous region anterior to the petiolar node. Waist single-segmented; petiolar node narrows to a point at the apex; subpetiolar process with a distinct, acutely angled projection with some erect setae. Gaster with a mixture of erect and appressed setae; first two tergites longer than the remaining ones; prominent sting present at the apex.

Male: TL ≈ 3.50-4.0, HL 0.66-0.71mm, HW 0.61-0.64mm, SL 0.17-0.18mm, EL 0.28-0.31mm, MeSL 1.42-1.53mm (n=4) (MEM specimens). Head, scape, pronotum, mesopleura, and apical portion of gaster yellowish brown; funiculus, propodeum, petiole, and anterior half or more of gaster dark brown; mesoscutum and legs pale yellow. Head small, almost circular looking, but longer than wide with a mixture of short, appressed setae and longer erect setae; eyes large, ovoid and distinctly convex; three ocelli present with dark pigmentation around their bases; mandibles reduced and indistinct with the rest of the mouth parts conspicuous; antennae 13-segmented; antennal scape about twice the length of the first funicular segment, but slightly shorter than the rest of the antennal segments. Mesosoma mostly smooth and shining; enlarged with four wings; propodeum with medial, smooth, shining area anterior to the petiolar node. Waist single-segmented with short and long erect setae; node roughly triangular in the lateral view, broadly rounded apically; subpetiolar process distinct with an acute tooth. Gaster with a mixture of short appressed setae and long erect setae; apical gastral segment coming to a distinct point, almost like a sting.

Diagnosis
Workers of B. chinensis can be recognized by their shiny, dark blackish appearance, lack of spines or other ornamentation, the single petiolar node, and sting. This species is similar in size to average sized fire ants, but differs by having only only node and by its nesting in wooded habitats. In the Southeast, it could be possibly be confused  with other ponerine ants (e.g. Hypoponera, Leptogenys, Pachcondyla, and Ponera), but differs by the the promesonotum being distinctly set off from the propodeum, by the very shiny mesopleura, and by large super colonial nesting behavior. A similar sized species in the related genus Pachycondyla, P. stigma, which also occurs in the U.S., 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
Brachyponera 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
Native Range: Asia, probably China or Japan

Australian: New Zealand (antwiki.org).
Nearctic: United States (antwiki.org).
Oriental: Cambodia, Philippines, Taiwan, Thailand, Vietnam (antwiki.org).
Palearctic: China, Democratic Peoples Republic of Korea, Japan, Republic of Korea (antwiki.org).

U.S. Distribution: AL, AR, CN, FL, GA, KY, MS, NC, NY, SC, TN, TX, VA, WA, WI (antweb.org, antwiki.org, MEM, Dunn and Menninger 2013, Guenard, 2009; Guénard and Dunn 2010, MacGown 2009 and Nelder et al, 2006).
Southeastern U.S. Distribution: AL, AR, FL, GA, MS, NC, SC, TN (MEM).

Acknowledgments
Thanks to Ryan J. Whitehouse for help with measuring specimens, comments on descriptions, photography of some specimens, and proofreading. 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
Bolton, B. 1995. A new general catalogue of the ants of the world. Harvard University Press: Cambridge, Massachusetts, USA.

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

Brown, W. L., Jr. 1958. A review of the ants of New Zealand. Acta Hymenopterologica 1:1-50.

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.

MacGown, J. A., H. Richter, and R. L. Brown. 2013. Notes and new distributional records of invasive ants in the southeastern United States. Midsouth Entomologist 6: 104-120.

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.

Schmidt, C. A.; Shattuck, S. O. 2014. The Higher Classification of the Ant Subfamily Ponerinae (Hymenoptera: Formicidae), with a Review of Ponerine Ecology and Behavior. Zootaxa 3817(1):1-242.

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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