Placopterus thoracicus (Olivier, 1795)

Chapman, Eric G., Leavengood, John M. & Dupuis, Julian R., 2025, The Cleridae and Thanerocleridae of eastern North America, with illustrated keys, updated distributions, and special emphasis on the Kentucky fauna, Zootaxa 5639 (1), pp. 1-88 : 64-65

Placopterus thoracicus (Olivier, 1795) ; Cleridae : Clerinae : Clerini

Illustrations: Plate 5-A. Key to clerid genera, couplet 14-D, couplet 15-D, couplet 17-A

Distribution: FL to southern PQ to SD to TX.

- Recorded from: AR, CT, DE, FL, GA, IA, IL, IN, KS, KY, MA, MD, ME, MI, MN, MO, NC, NE, NH, NJ, NY, OH, OK, PA, SC, SD, TN, TX, VA, VT, WI, WV, Quebec and Ontario ( Bøving & Champlain 1920; Knull 1951; Papp 1960; Foster & Barr 1972; Barr 1975; Gosling 1980; Downie & Arnett 1996; Mawdsley 1999; Eliason & Potter 2000; BugGuide). Opitz (2011) presents an ambiguous map (see remarks in Distribution of Neorthopleura texana ) and added no new distributional knowledge to the species. Wolcott (1947) incorrectly recorded it from California and Mexico. Placopterus does not occur in California. The Mexican records are probable misidentifications.

- New State Record: DELAWARE: Kent County : 0.5 mi N of Dinahs Corner, 39°11’29”N, 75°38’50”W, at black light, 10-V-2002, R . F. C. Naczi (RNC, 1). MINNESOTA: Crow Wing County: Brainerd Lum Park , 46.3682°N, 94.1635°W, in forest pest survey trap, 30-VI-14-VII-2020, N. G. ( RNC, 1) . WEST VIRGINIA: Kanawha County: Nitro, Brookhaven , 4-V-2000, S. M. Clark ( WVDA, 1) .

Kentucky counties (Map 29): Bullitt (2), Crittenden (1), Fayette (3), Garrard (1), Hardin (1), Jefferson (6), Madison

(6), Meade (3), Owen (4), Pendleton (1). Most Kentucky specimens were collected in the central part of the state in the Interior Plateau ecoregion.

Years: 1948 (1), 1952 (1), 1953 (1), 1959 (1), 1961 (1), 1966 (1), 1971 (1), 1973 (1), 1976 (1), 1995 (1), 1998 (1),

2006 (2), 2007 (2), 2009 (4), 2010 (2), 2012 (5), 2013 (1), 2015 (1)

Months: April (8), May (9), June (8), July (3)

Collections (28): CEWC (5), EGC-CRC (1), JMLC (11), UKIC (11)

Collection methods: Malaise trap (11), blacklight (5), fogging (1)

Natural History: Bøving & Champlain (1920) reported the following: They considered it a predator of smaller wood boring beetles in deciduous trees, especially the shothole borer ( Scolytus rugulosus (Muller)) . In hickory

( Carya ) in Connecticut, larvae were found to (1) overwinter in abandoned pupal cells of the weevil Magdalis olyra

(Herbst) where they presumably feed on the weevil larvae and (2) in the galleries of Oncideres (undoubtedly O.

cingulata (Say); Cerambycidae ) where the hickory twigs were also infested with the scolytine Chramesus hicoriae

LeConte. Also found among infestations of small cerambycids in butternut ( Juglans cinerea ) in Connecticut.

Knull (1932) reported a larva from a small dead witch hazel ( Hamamelis virginiana ) infested with the scolytine

Lymantor decipiens (LeConte) in Ohio, and that adults were reared from willow ( Salix ) with infestations of the buprestid Anthaxia viridiconris (Say) , the scolytine Micracis swainei Black , and the cerambycid Pogonocherus parvulus LeConte. Knull (1934) reported larvae feeding on Agrilus defectus LeConte in dead white oak ( Quercus alba ) in Ohio. Knull (1951) reported rearing it from red maple ( Acer rubrum ) infested with the false click beetle

Melasis pectinicornis Melsheimer in Ohio. Foster and Barr (1972) reported rearings from the nest cells of the wasps

Pemphredon lethifer Wagner and Trypoxylon in Indiana. Gosling (1980) reported rearing it from oak branches infested with the cerambycid Anelaphus villosus (Newman) , collected from dead sumac ( Rhus ) branches by beating,

and mentioned that it also preys on false click beetles ( Eucnemidae ). Eliason & Potter (2000) dissected larvae out of cynipid stem galls ( Callirhytus cornigera (Osten Sacken)) on pin oak, however it was unclear which of the many insects occupying the galls were preyed upon by this clerid. Dillon & Dillon (1961) reported that it occurs in damp meadows on foliage and Gosling (1980) reported that it is attracted to lights in oak-hickory forests. Dorshorst & Young (2008) reported collections primarily from oak barrens, oak savannas and prairies and by beating black locust ( Robinia pseudoacacia ) in Wisconsin; collecting methods included flight intercept and Malaise traps, and at blacklights. Also collected by Malaise traps, at blacklights and by fogging in a deciduous forest in Kentucky by authors EGC and JML.

Mimicry: Thought to be part of a mimicry ring in eastern North America that includes members of the families Buprestidae , Cantharidae , Elateridae , Lampyridae , Meloidae , Ptilodactylidae , and other clerids ( Chariessa , Monophylla , Pyticeroides ) ( Mawdsley 1994).

Chemical lures: Ethanol (Montgommery & Wargo 1983)