The invasion route of the gill parasite Urocleidus adspectus Mueller, 1936 (Monogenea: Ancyrocephalinae)

Abstract

Urocleidus adspectus is transmitted experimentally to yellow perch (Perca flavescens) and the route of invasion and the behaviour of the parasite during the migration to the gills of the host is studied.The oncomiracidia invade the full length of the host and. as postoncomiracidia, attach at secluded sites such as beneath scales, at the base of fins, and in nooks in the body surface. The postoncomiracidia gradually migrate anteriorly and reach the gills by entering the opercular cavity and possibly the buccal cavity. In young-of-the-year perch, migrating worms appear to invade the primary lamella from the base or from the distal tip. In older perch the majority appear to invade the primary lamella from the base. Over 90% of the postoncomiracidia reach the gills of the young perch by day 5 postinfection and experimental studies indicate that few worms are dislodged during the migration.

Parasite fauna of introduced pumpkinseed fish Lepomis gibbosus: first British record of Onchocleidus dispar (Monogenea)

“…The sex-biased parasitism in L. gibbosus may also have an ecological basis. The oviparous lifecycle of O. dispar is unknown; however, closely related species release eggs which are expelled from the host by respiratory currents and sink to the substrate (Olsen 1974, Cone & Burt 1981, King & Cone 2008. Eggs of most monopisthocotylean parasites hatch into ciliated oncomiracidia which infect new hosts close to the site of hatching (Smyth & Halton 1983).…”

“…Eggs of most monopisthocotylean parasites hatch into ciliated oncomiracidia which infect new hosts close to the site of hatching (Smyth & Halton 1983). The oncomiracidia attach to the skin of new hosts before losing their ciliated cells and migrating to the gills by entry through the opercular and buccal cavities (Cone & Burt 1981, Euzet & Combes 1998, Vadstein et al 2004. Therefore, male L. gibbosus will have an increased exposure to the free-living stages of O. dispar when constructing nests on the lake bed.…”

Invasion of the shovelnose ray (Rhinobatos typus) by Neoheterocotyle rhinobatidis and Merizocotyle icopae (Monogenea: Monocotylidae)

“…Indeed, the few studies which have examined the route by which monopisthocotylean monogeneans infect their fish hosts confirm that infection occurs in this way (e.g. Cone & Burt, 1981 ;Kearn, 1984). Polystomes, internal polyopisthocotylean monogenean parasites of anurans, also first attach to the skin of their host and then undergo a series of complex migrations (Euzet & Combes, 1998).…”

“…To date, all studies on host invasion by monopisthocotylean monogeneans have demonstrated that, regardless of the final site of attachment of the adult parasite, the first point of contact for the larva is the body surface of the host. For example, the larvae of Urocleidus adspectus (Dactylogyridae) attach to the skin of their teleost host and then migrate to their final attachment site, the gills (Cone & Burt, 1981) and the larvae of Entobdella soleae (Capsalidae) migrate from the upper to the lower surface of their teleost flatfish host (Kearn, 1984). Whittington & Ernst (2002) demonstrated that larvae of the ' skin' parasite Benedenia lutjani (Capsalidae) initially attach anywhere on the body surface of their teleost host, but then migrate to the branchiostegal membranes via the pelvic fins.…”

Gill worm Ancyrocephalus percae (Ergens 1966) outbreak negatively impacts the Eurasian perch Perca fluviatilis L. stock of Lake Constance, Germany

“…Adult trematodes locate mainly on the gills of the host, where they produce eggs that are released into the aquatic environment. The eggs hatch into free‐living, ciliated oncomiracidia, which seek a host and migrate as post‐oncomiracidia to the gills, where they grow to adulthood (Chubb ; Cone & Burt ). Two species have been found infecting Eurasian perch, Perca fluviatilis L.: A. paradoxus and A. percae .…”