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Occurrence of Adult and Developmental Stages of Proctoeces maculatus (Trematoda: Digenea) in the Gastropod Crepidula convexa

1985; Wiley; Volume: 104; Issue: 3 Linguagem: Inglês

10.2307/3226438

2325-5145

P. Aitken-Ander, Norman L. Levin,

Aquatic Invertebrate Ecology and Behavior

Metacercaria and unencysted juvenile and adult Protoeces maculatus are reported in the gastropod Crepidula convexa. The metacercaria and metacercarial cyst are described. Staining of the encysted worms and the cyst wall with toluidine blue and Alcian blue indicates that the metacercaria has cystogenous glands. The cyst appears to be of parasite origin, and there is no marked host response. Sexually mature worms found in C. convexa are true adults and not metacercaria. Ovigerous parasites migrate to the nephridium of the snail where eggs are deposited and may leave the host via the renal pore. The incidence of infection in snails collected at Breezy Point, New York was 7-75% during the year and was always higher in females. P. maculatus can complete its life cycle without a vertebrate host using C. convexa as an alternative definitive host. In 1981, many specimens of Crepidula convexa Say collected at Breezy Point, New York were found to be infected with a digenetic trematode. Based upon examination of whole mounts of juvenile and adult worms, the parasite was identified as Proctoeces maculatus (Looss, 1901) Odhner, 1911. The present study was initiated to investigate the host-parasite relationship between C. convexa and P. maculatus and to study the developmental stages of the worm in this snail. Proctoeces spp. have been reported from the hindgut of several families of bottom-feeding fishes, primarily Sparidae and Labridae (see Freeman & Llewellyn, 1958; Prevot, 1965; Wardle, 1980). The asexual and larval stages of P. maculatus have been found in several bivalves including the mussels Mytilus edulis, Brachiodontes recurvus, and Mytilus galloprovincialis (Hopkins, 1954; Prevot, 1965; Stunkard & Uzmann, 1959). Unencysted, metacercariae of P. maculatus have been described from the bivalves Scrobicularia plana, Mytilus edulis, and Crassostrea virginica, as well as from the gastropod Rissoa splendida (see Freeman & Llewellyn, 1958; Machkevesky & Parukhin, 1980; Uzmann, 1953; Winstead & Couch, 1981). Wardle (1980) reported finding unencysted, non-progenetic metacercariae of P. maculatus in the mussels Ischadium recurvum (=B. recurvis) and Mytilopsis leucopheata (=Congeria leucopheata). The term progenetic is applied to sexually mature, ovigerous digenetic trematodes occurring in invertebrates. The worms are considered 1 We thank Dr. David Franz for his critical reading of the manuscript and his many helpful