Muscidae

Family Muscidae

The hematophagous muscids in the Nearctic Region are exotic species in the subfamily Stomoxyinae. Only two species of Stomoxyinae occur in the Park. The face fly, Musca autumnalis DeGeer, is also an exotic species that feeds on the mucus around the eyes of large animals (Gilreath & Adkins 1982). Although not a blood feeder adults of M. autumnalis are anautogenous and require protein meals from large mammals (Moon 2002). These flies feed on living tissue and transmit pathogens to their hosts.

Haematobia irritans (Linnaeus)

Collections: North Carolina, Haywood Co., Sterling, 2 July 1993, fogged, coll. unknown; Swain Co., Oconaluftee/Ravensford, ex cattle, August 2002.

Haematobia irritans is an ectoparasite of cattle and leaves its host only when disturbed to lay eggs in feces or to consume fluids from fresh cow dung. It is restricted to areas of the Park with cattle. Haematobia irritans was historically present in Cades Cove but cattle have been removed from that area. It probably will not become a pest of elk or deer because the dung of these animals desiccates quickly and is not conducive for larval development. Haematobia irritans is a potential vector of several helminths and microbial pathogens, including the filarial nematode Stephanofilaria stilesi (Hibler) (Moon 2002).

Musca autumnalis DeGeer

Collections: Tennessee, Blount Co., Cades Cove, 11 June 2003; Sevier Co., Brushy Mountain (1467 meters, 35.6762°N, 83.4305°W), 29 May 1999, Malaise trap, coll. G. Dahlem.

Musca autumnalis overwinters in Park buildings and appears to be a pest of domesticated animals in the Park. At least two species of Thelazia (Nematoda: Thelazioidea) can develop in Nearctic strains of M. autumnalis (O’Hara & Kennedy 1989; 1991).

Stomoxys calcitrans (Linnaeus)

Collections: North Carolina, Haywood Co., Big Creek near Park boundary, 17 May 2001, biting humans; Cataloochee, 3 May 2002, in Palmer Chapel, 22 July 2002, biting elk; Purchase Knob, 23 July 2002, on truck, 31 July 2003, biting feral dog; Swain Co., Deep Creek horse stable (610 meters, 35.4732°N, 83.4295°W), 23 May 2001; Tow String Road, 10 May 2001, biting humans; Mount Weaver Overlook on US 441, 10 May 2001; Oconaluftee/Ravensford, 10 May 2001, on truck, 4 June 2002, biting cows, pigs, and sheep; Straight Fork, 15 May 2001, on truck; Road to Clingman’s Dome (1584 meters, 35.6088°N, 83.4392°W), 20 June 2001; Tow String Road, 15 August 2001, biting human; Smokemont stable, 15 August 2002, biting horses; Twentymile Creek ranger station, 16 May 2002, in bog; Tennessee, Blount Co., Cades Cove, 25 May 2001, biting horses, 24 July 1999, 19 October–7 November 2000, Malaise trap, coll. J. Cooper, Parker, Stocks, & Petersen, 4 August 2003, biting llama; Cocke Co., Cosby, 29 May 2001, on truck; Sevier Co., Brushy Mountain, 29 May 1999, Malaise trap, coll. G. Dahlem, 23 October 2000, Malaise trap, coll. Parker, Stocks, & Petersen; Sugarlands trailhead (568 meters, 35.6631°N, 83.5259°W), 10 May 2001; Sugarlands horse stable, 5 June 2002, biting horses; Copeland Creek, 22 June 2002, biting deer; Goshen Prong, 25 October–10 November 2001, Malaise trap, I. Stocks.

The stable fly, S. calcitrans, was one of the most frequently encountered biting flies in the Park. The only areas that were apparently devoid of this species were high elevations such as Clingman’s Dome. Black body traps, truck traps, Malaise traps, and active netting failed to collect any specimens above 1600 meters. Stomoxys calcitrans readily bites humans, domesticated animals, deer, feral pigs, and elk. Stomoxys calcitrans is a potential vector of a spirurid nematode (Habronema microstoma Schneider) of horses, equine infectious anemia virus, and bovine leukosis viruses (Moon 2002). Stomoxyinae are also vectors of some Trypanosoma species to mammals (Zumpt 1973). The flies trapped on Brushy Mountain and in Cades Cove were infested with phoretic mites, Pediculaster trombidiphilus Rack & Vercammen­Grandjean (Acari: Pygmephoridae), on their abdomens and thoraxes. Pediculaster trombidiphilus was originally described from Africa and might be exotic (Rack & Vercammen­Grandjean 1979).