title: Anatomical modifications, viviparous reproduction and hydraulic expulsion of larvae by Cephenemyia nasopharyngeal bot flies of deer.
abstract: Several specialized adaptations of the reproductive and respiratory systems associated with the retention and expulsion of larvae in ovoviviparous Cephenemyia species (Diptera: Oestridae) are described and illustrated. In these flies the anterior section of the common oviduct is modified into a large sac-like uterus that contains larvae, and the posterior section is modified into a larvipositor with a central tubular vagina. During larviposition, contraction of abdominal muscles forces haemolymph into a perivaginal sinus, causing a hydraulically driven exsertion of the larvipositor. A group of larvae and uterine fluid sealed off within the lumen of the vagina are then expelled from the vulva via hydraulic pressure as the stretched vagina is compressed. A one-way, non-return valve between the uterus and vagina prevents a reflux of larvae upward into the uterus during larviposition. All mutually dependent actions associated with larviposition occur almost simultaneously. All species have evolved a similar mechanism of expelling their larvae, but the shape of the non-return valve is different in each species studied.
authors.affiliation: Division of Organisms and Environment, Department of Environmental Science, Policy and Management, University of California, Berkeley, CA, U.S.A.
authors.forename: J R
authors.initials: JR
authors.lastname: Anderson
mesh_terms: D000818:Animals; D003670:Deer; D004175:Diptera / Q000502:physiology*; D005260:Female; D007814:Larva / Q000502:physiology; D009198:Myiasis / Q000662:veterinary*; D014599:Uterus / Q000033:anatomy & histology / Q000502:physiology; D052286:Viviparity, Nonmammalian / Q000502:physiology*
keywords: Botflies; hydraulic larviposition; larviposition behaviour; larvipositor; oestrids; ovoviviparous; viviparous