Acanthinus argentinus (Pic, 1913)

Gimmel, Matthew L., 2010, Acanthinus argentinus (PIC) Newly Established in the Southeastern United States (Coleoptera: Anthicidae), The Coleopterists Bulletin 64 (1), pp. 94-95 : 94-95

ACANTHINUS ARGENTINUS (PIC) NEWLY ESTABLISHED IN THE SOUTHEASTERN UNITED STATES ( COLEOPTERA : ANTHICIDAE )

Specimens of Acanthinus argentinus ( Pic, 1913) , a fast-running, ant-mimicking beetle ( Figs. 1, 2 ) were collected at lights at night in southern Louisiana during September 2009. Werner (1970a) provided a habitus illustration and line drawing of the prothorax that permitted positive identification. This species may be distinguished from the two other Acanthinus LaFérte-Senéctère species in North America that have a transverse pronotal impression (anterior to basal impressed line) as follows (key modified from Werner 1970a, b):

1. Elytra with golden to almost brown pubescence in basal half (Virginia to Kansas, south to Florida and Texas)...................................... ................................... A. myrmecops (Casey)

1′. Elytra essentially glabrous, except for tactile setae............................................................... 2

2. Pronotum almost flat in profile at level of constriction (southeastern USA from South Carolina to Texas)...... A. scitulus (LeConte)

2′. Pronotum with a deep saddle at constriction (adventive in Florida and Louisiana) ............. ........................................ A. argentinus (Pic)

Don Chandler (University of New Hampshire Insect Collection, Durham, NH) and Mike Thomas (Florida State Collection of Arthropods [ FSCA], Gainesville, FL) (personal communications) informed me of specimens previously collected in peninsular Florida. The collection data for all specimens are as follows: (n = 13) USA: FLORIDA: Palm Beach Co.: Lake Worth , Geneva Lakes Court, 9 May 2003, blacklight and MV light, coll. V. Golia (1); same data, except 13 May 2003 (1), 1 Jun 2003 (1), and 17 Aug 2003 (1), all in FSCA; Okeechobee Co. : South Florida Water Management District , 05 Oct 2007, coll. A. Samayoa (1), FSCA; LOUISIANA: Lafourche Par.: Golden Meadow, 29°23.559′N 90°16.474′W, 03 September 2009, at light, coll. M. Gimmel and J.-S. Park (8), Louisiana State Arthropod Museum ( LSAM). In addition to these specimen records, submissions to the popular arthropod identification website <http://bugguide.net> include photos clearly representing members of this species from St. Lucie Co. (02 Jun 2007) and Kissimmee, Osceola Co. , Florida (01 Jul 2006), suggesting that the species is becoming more widespread in Florida. This species’ native range includes Argentina, Paraguay, and Brazil (Werner 1970a). These specimens represent the first records for the United States. The shape of the apex of the lobes of the male eighth sternum was comparatively illustrated (Werner 1970a) for specimens from western Argentina (“curved to a point”) versus those from Misiones, Argentina, and Brazil (“obliquely truncate”). The apex is obliquely truncate in the Louisiana specimens, suggesting a Brazilian origin. The Okeechobee Co., Florida record was from a survey of insects associated with tropical soda apple ( Solanum viarum Dunal ), a recently introduced noxious weed. The mechanism of transport for this species is unknown, but the Louisiana specimens were collected in the proximity of Bayou Lafourche, which intersects with the Gulf Intracoastal Waterway, a major shipping route, in Larose, Louisiana, about 24 km north of the collection site .

This manuscript is approved for publication by the Director, Louisiana Agricultural Experiment Station , as publication number 2009-234-3918 .

Figures

Figs. 1–2. Acanthinus argentinus, male. 1) Dorsal view of habitus; 2) Lateral view of habitus.