Emergence and Flight Activity of Salt-Marsh Horse Flies and Deer Flies1,2

Abstract

Bionomics of 4 common Tabanidae (Diptera) was studied by use of emergence traps, Manitoba fly traps, and insect sweep-net collections. Emergence locations and sex ratios are presented. Female Tabanus nigrovittatus Macquart predominated on a New Jersey salt marsh near an upland area, apparently being concentrated by southeast breezes. The tall, dense, marsh-upland border vegetation apparently presented a geographical barrier to flight farther inland and formed an environmental trap at some locations. Aggregation to geographically pronounced locations occurred on the marsh. Many female Chrysops atlanticus Pechuman sought a blood meal on the marsh during the period of adult emergence, but those seeking blood shifted entirely from the marsh to the upland, about 150 yards from the marsh edge soon after adults had ceased emerging.