Two Simuliids Found Feeding on Turkeys in Virginia

Abstract

Simulium nigroparvum was found abundantly during 1936 to 1939 (incl.) in the western and piedmont mountainous regions of the State. Immature stages have been collected from early April to Nov. in 23 counties; 15 of which were west of the Blue Ridge and 7 in the foothills. The natural habitat was in the larger rivers and creeks which have a rather flat, rocky bottom with some vegetation (especially water willow, Dianthera americana), and where the water current was rapid (4-5 ft. per sec.). Nearly all collections have been in such type streams, with very few to none found in medium size streams less than 20 ft. wide. Large numbers of [female][female] fed on turkeys from mid May to mid Oct.[long dash]the maximum June, July and Aug. Females of S. slossanae were taken feeding in small numbers only in New Kent county, eastern Virginia, on two occasions, Aug. 1937, and July 1938. Adults have not been reared from pupae and the habitat is not known. The blackflies have been observed to. feed only on the head and neck region of a turkey. They have been collected feeding at all hours from 5:30 AM to 7:30 PM in summer, but the best period was usually about midafternoon and midafternoon. Two to 3 min. are required to engorge, and the blackflies are not easily disturbed when once attacked to feed. Temp., atmospheric pressure and relative humidity are important in- fluencing factors in feeding activity. The optimum conditions were 75-85[degree] F, low atmospheric pressure, and a moderately high relative humidity. The [female][female] of S. nigroparvum have been collected in large numbers 6-10 miles, and in small numbers 15 miles distant from the known breeding ground. Adults have been taken feeding on a turkey at 4000 ft. elevation. All attempts to induce feeding on a turkey in cages were unsuccessful.