Rhamphomyia marginata (Diptera Classification)
(abbreviated from Bartak, 1980)
Male: Typical Rhamphomyia (Pararhamphomyia) species; black ground color with grey dusting on thorax and abdomen, brownish stripes under dorsocentral setae. Wings clear.
Female: wings greatly broadened, with posteroapical margin straight, and a wide brown band around wing margin.
This species shows sex role reversal, as described by Svensson (1997), with ornamented females forming swarms. Swarms of up to 40 females are found in forest clearings for 2-3 hours around sunset. Males bring nuptial prey (usually male midges) into swarm, but often leave the swarm without mating. In central Europe, adults have been found from late April to late May.
This species exhibits one of the most striking examples of female ornamentation in the Empidinae. The bicolored female wings have approximately 1.6 times the area of the male wings. Males are apparently very choosy in selecting a mate, and prefer courting in larger female swarms.
Central and western Europe, including Great Britain and southern Sweden as well as Finland