The Phoretic Association of Diplogaster Coprophila Sudhaus & Rehfeld, 1990 (Diplogastridae) From Cow Dung With Its Carriers, in Particular Flies of the Family Sepsidae

Diplogaster coprophila is specifically phoretic on Sepsidae, Sphaeroceridae (Diptera) and also Cercyon species (Coleoptera, Hydrophilidae). Dauerlarvae of D. coprophila were present on 59% of sepsids caught with emergence traps and 13% of those that landed on a cow pat in the field. Both sexes of the flies were infested. In laboratory experiments, using Sepsis punctum as carriers, dauerlarvae were found to aggregate on the fly pupae where they wait motionless until the metamorphosis of the fly is completed. At eclosion, the dauerlarvae move to the abdomen of the fly and enter the genital opening; they are present in the reproductive system of female and male sepsids. Dauerlarvae are transmitted from male to female during copulation. They cannot leave the carriers by their own volition but are placed in the dung by the female fly during oviposition. Phoresy is physiologically obligatory for D. coprophila. Dauerlarvae fail to develop unless they spend some time on a carrier.