An experimental investigation of a direct life-cycle inReighardia sternae(Diesing, 1864), a pentastomid parasite of the herring gull (Larus argentatus)

Abstract

A direct life-cycle inReighardia sternae, a cephalobaenid pentastomid of gulls was investigated: the work was prompted by a report of eggs and larvae recovered from the stomach and intestine of a naturally infected gull.Infective pentastomid eggs were obtained by surgically transplanting maturing femaleReighardia, taken from freshly shot wild gulls, into captive recipients. Faecal material from birds thus artificially infected was collected daily and examined for eggs. Eggs were force fed to 33 hand-reared (from eggs or nestlings) juvenile gulls which were selected at random and sacrificed at intervals thereafter and examined for pentastomids.One hour after infection, primary larvae appear in the body cavity where they moult immediately. They grow steadily and by 27–35 days are sexually differentiated, and by 66 days have copulated. Fertilized females take a further 116 days to produce eggs by which time they are 7·6 cm long.The complex migrations undertaken by developing larvae in the gull, and the problems of the mechanism of direct transmission, are discussed.

On the systematics of the pentastomid genus Porocephalus (Humboldt, 1811) with descriptions of two new species

“…First, pentastomids, being arthropods (Riley, Banaja & James, 1978) moult frequently and, according to Fain (1961), hook size and annulus number increase at each moult. This coupled with the fact that female porocephalids achieve patency before reaching maximum size and that males also exhibit precocious sexual development (copulation usually occurs when both sexes are of a similar size (Sambon, 1922;Hett, 1924;Riley, 1972;Banaja, James & Riley, 1975) weeks and females continue to produce eggs in considerable numbers for at least 3 years (Banaja, James & Riley, 1976;plus unpublished observations). Clearly the potential number of moults in a life-cycle of this duration might be very great.…”

A new Late Cambrian pentastomid and a review of the relationships of this parasitic group

“…cichlids and barbs, all the mentioned groups of tetrapods, and also at least one insect species, may act as intermediate hosts in the life cycle of Recent tongue worms. Direct development in a single host also has been reported (Banaja et al 1975;Riley 1986). This diversity of life cycles has caused difficulties in reconstructing the ancestral life cycle (cf.…”

“…Few other scientists have studied the Pentastomida thereafter. More recent authorities are Wolfgang Bö ckeler, Kiel (e.g., Bö ckeler & Vauk-Hentzelt 1979;Storch & Bö ckeler 1979, 1982Bö ckeler 1982Bö ckeler , 1984aBö ckeler & Storch 1990;Storch et al 1990;Thomas & Bö ckeler 1992, Thomas et al 1999a and John Riley, Dundee (e.g., Riley 1972, 1973a, b, 1976, 1983, 1986, 1992, 1994, 1996Banaja et al 1975;Ali & Riley 1983Winch & Riley 1986a, b;Jones & Riley 1991;Jones et al 1992;McAllister et al 1993;Buckle et al 1997;Riley et al 1978Riley et al , 1985Riley et al , 1987Riley et al , 1990Riley et al , 1991Riley et al , 1997Riley & Self 1980, 1981a, b, 1982Riley & Heideman 1998;Riley & Huchzermeyer 1995, 1996.…”

Studies on the behaviour, and development in fish, ofSubtriquetra subtriquetra: a uniquely free-living pentastomid larva from a crocodilian

“…Most larval pentastomids encyst within the intermediate host and the stages between the primary and infective larva are totally (see Esslinger, 1962a;Vargas, 1970;Ali & Riley, 1983;Winch & Riley, 1986) or partially (see Fain & Mortelmans, 1960) devoid of hooks. Apart from Subtriquetra only one other pentastomid, the cephalobaenid Reighardia sternae remains free throughout development (Banaja, James & Riley, 1975) and both these species always retain hooks. Pentastomid larvae also exhibit degrees of site selection (summarized by Riley, 1986) but Subtriquetra, which develops exclusively in the swim-bladder, is the most restricted of all.…”