Staphylinidae of Eastern Canada and Adjacent United States Part 1

Figure 7.3.2 Platydracus mysticus (Erichson), pronotum. 7.8.1 P. fossator (Gravenhorst), dorsal habitus of maculate form.

7.8.2 P. fossator, dorsal habitus of immaculate form. 11.12.1 P. fossator, swept from tall grass along a driveway.

Individuals with the typical apical orange spot on the elytron are distinguished from other Staphylinina (Gravenhorst) by that character alone (Fig. 7.8.1). Specimens lacking the spot (with a completely black body) are identified as Platydracus using the characters in the key, and to fossator using the following combination of characters: elytra completely black (Fig. 7.8.2), abdomen lacking dense patches of golden or black velvet setae (Fig. 7.8.2), pronotum lacking complete impunctate median line (Fig. 7.6.2), and eyes distinctly longer than the temple.

This species is widespread, occurring from central North America east to the coast and south to Arizona, Texas and Florida. Specimens from west of the Great Plains were all collected at high elevations. Platydracus fossator is quite common south of the Canadian border and occurs regularly at some sites in southern Canada (Map 16). This species is newly recorded from Nova Scotia, Ohio, and Pennsylvania:

CANADA: NS: Annapolis Co., Middleton, 20-VII-1928, W.J. Brown, 1 (CNC). Antigonish Co., Brierly Brook, 20-VIII-1954, Douglas C. Ferguson, 1 (NMSC). Colchester Co., Glenholme (Roger’s Field), 45.42 -63.51, wild blueberry field, pitfall trap, 25-VIII-2009, C. Cutler, 2 (NSAC); Glenholme (Webb Field), 45.41 -63.51, wild blueberry field, pitfall trap, 25-VIII-2009, C. Cutler, 3 (NSAC); Kemptown, 4-VIII-1999, J. Ogden, 1 (NSNR); Portapique, in cow dung, 31-VII-1929, Frost, 1 (MCZ). Digby Co., Digby, 14-XI-1960, C.J.S. Fox, 1 (ACNS); South Range/Porter’s Lake, ‘Crawling in mowed lawn during midday’, 3-VIII-2003, G.D. Selig, (GSC); Weymouth, 14-VIII-1990, 1(MCZ). Hants Co., Monte Vista Farm, 14-VIII-1966, Kenneth A. Neil, 1 (NSMC).

UNITED STATES: OH: Adams Co., 20-VIII-1967, 1 (Hamilton). Franklin Co., Columbus, 1 (OSU). Stark Co., 1-VII-1937, 1 (INHS). PA: 69 specimens.

Eastern Canada: ON, QC, NB, NS

Adjacent U.S.: MI, IN, OH, PA, NY, VT, NH, ME (All ECAS states)

Platydracus fossator has been collected in ECAS from March to October, with a marked increase in abundance during July and August.

While this species inhabits a variety of forest types (except boreal), a large proportion of specimens were collected from open forests with conifers and/or oak trees, including oak savannah. Platydracus fossator occurs at carrion, dung, and at decaying soft fungi including Pleurotus ostreatus Fries (Cline and Leschen 2005), and is often encountered flying or walking as it disperses between these microhabitats (Fig. 11.12.1).  Both adults and larvae have been reared on a diet of muscoid flies (Schmidt 1999).