Synonyms and other taxonomic changes
Rhamphomyia longicauda Loew, 1861
Explanation of Names
From the Latin "longus" (long) + "cauda" (tail); refers to the female's abdomen, which is relatively long for a dance fly but does not exceed the wingtips when at rest.
Size
body length about 8-10 mm (guide images)
Identification
Adult: all black except for red or orange eyes, light-colored underside and coxae, and orangish inflatable abdominal sacs in female; head relatively small with slender beak slightly longer than head; antennae slightly longer than head, diverging at base into a curving V shape; female midlegs and hindlegs with long stiff scale-like hairs forming a fringe; male legs bare; male eyes meet at midline, whereas female eyes do not meet.
Range
Northeastern North America: Quebec south to North Carolina, west to Missouri and Michigan
Habitat
Understory of wet deciduous woods and wooded riparian areas; adults are often seen resting on low vegetation during the day.
Larvae develop in the soil near water.
Season
Adults fly from May to July
Food
Larvae and adult males prey on small insects; adult females do not hunt - they only eat prey items brought to them by males.
Remarks
Adult females congregate in a swarm above vegetation near water around sunset, and inflate abdominal sacs in an attempt to fool males into thinking the swollen abdomens are full of ripe eggs. The hairy legs are held alongside the abdomen in flight, supposedly to accentuate abdominal size. Males hunt small insects and bring the dead prey as "nuptial gifts" to females in exchange for a chance to mate. Males prefer to mate with the fattest and hairiest females, but the cost of being hairy is an increased chance of being caught in spider webs. See Internet References below for more information on mating behavior.
Adults are very common in appropriate habitat in southern Ontario. If approached quickly, they fly a short distance to another leaf; if approached slowly, they often walk to the far edge of the leaf they're on, then onto its underside.
R. longicauda cannot be placed in any currently described subgenus of Rhamphomyia.
Print References
Bussière, L.F., Gwynne, D.T. and Brooks, R. (2008), Contrasting sexual selection on males and females in a role-reversed swarming dance fly,
Rhamphomyia longicauda Loew (Diptera: Empididae). Journal of Evolutionary Biology, 21: 1683-1691 (
Full Text)
Funk, D.H. and D.W. Tallamy (2000). Courtship role reversal and deceptive signals in the long-tailed dance fly,
Rhamphomyia longicauda. in
Animal Behavior 59: 411-421. (
Abstract)
Gwynne, D.T. and L.F. Bussière (2002). Female mating swarms increase predation risk in a ‘role-reversed’ dance fly (Diptera: Empididae: Rhamphomyia longicauda Loew). Behaviour 139:1425-1430.
Newkirk, M. R. (1970). Biology of the Longtailed Dance Fly, Rhamphomyia longicauda (Diptera: Enipididae); a New Look at Swarming, Ann. Entomol. Soc. Amer., 63 (5): 1407–1412
Marshall, color photograph--460.4 (female), 460.5 (male)
(1)Internet References
Short article on mating behavior by Amanda Tromans (
Nature, 2000) with photo by D.H. Funk of female's inflated abdomen.
distribution (The Diptera Site, USDA) (link dead 2012)
presence in North Carolina; list (North Carolina State U.)(link dead 2012)
presence in Ontario; list from Ojibway Prairie, Windsor (U. of Guelph Insect Collection)
