Cercariae Of Cryptocotyle Lingua Research Articles

Behavioural responses of the cercariae of Cryptocotyle lingua (Digenea: Heterophyidae) to computer-controlled shadow sequences

The cercariae of Cryptocotyle lingua have a brief but active life during which they do not feed. In order to maximize the probability of infection they must respond to a variety of host-related stimuli yet conserve their finite energy reserves by minimizing unnecessary muscular activity. In laboratory experiments, simulated shadows representing the passage of a fish host were found to increase population activity levels. Evidence was also found for a relationship between shadow duration and the duration of subsequent bursts of swimming activity. Adaptation to continuous shadowing was recorded, its onset and magnitude being dependent on both the frequency and duration of shadows delivered. As cercariae aged they became less responsive to shadow stimuli, especially those of short duration.

New marine hosts for Parorchis acanthus, Cryptocotyle lingua, Maritrema megametrios, and Maritrema gratiosum, trematodes of birds from British Columbia, Canada

New molluscan, crustacean, and avian hosts were found for four species of digenetic trematodes in Vancouver, British Columbia, from 1973 to 1977. The rediae and cercariae of Parorchis acanthus (Nicoll) were discovered in Nucella lamellosa (Gmelin). Adults were recovered after 19 days from experimental feedings of the metacercariae to a newly hatched domestic chick. The cercariae of Cryptocotyle lingua (Creplin) from the snail Littorina scutulata Gould were used to infect young fish, Leptocottus armatus Girard, Oligocottus maculosus Girard, and Platichthys stellatus (Pallas). These fish, infected with the metacercariae, were fed to newly hatched gulls, Larus glaucescens Naumann, and mature worms were found in the anterior half of the intestine after 14 and 21 days. The metacercariae of Maritrema megametrios Deblock and Rausch, found in Orchestia traskiana Stimpson and Gnorimosphaeroma oregonense (Dana), became ovigerous in Locke's solution at 40 °C at 48 h. Natural infections were found in Larus Philadelphia (Ord). The metacercariae of Maritrema gratiosum Nicoll, found in Balanus glandula Darwin, also became ovigerous in vitro. Adults were found with two other microphallid species in the intestine of one Bucephala islandica (Gmelin).

Stereoscan Studies of Cercariae, Metacercariae, and Adults of Cryptocotyle lingua (Creplin 1825) Fischoeder 1903 (Trematoda: Heterophyidae)

The cercaria of Cryptocotyle lingua has simple pointed spines all over the body. Four pointed modified spines occur dorsally in the mouth, and similar spines surround the openings of the penetration glands. The modified spines are shed shortly after penetration and encystment in the fish host. Less than a week after encystment, cytoplasmic folds develop all over the tegument. After about 4 weeks the cytoplasmic folds have disappeared and the spines are now flattened and serrated. The external surface of adults from herring gulls is very similar to that of mature metacercariae. It is provided with scalelike serrated spines which are especially well developed ventrally on the anterior end.

The ultrastructure of the body wall and associated structures of the cercaria of Cryptocotyle lingua (Creplin) (Digenea: Heterophyidae) from Littorina littorea (L.).

The outer layer of the syncytial epidermis of the cercaria of Cryptocotyle lingua contains five types of membrane bound secretion bodies. Those with fibrillar contents predominate anteriorly and ventrally and are probably responsible for a surface coat to be secreted later. The epidermal cell bodies are consistently divided into a distal portion packed with secretion bodies and a narrow proximal portion containing the nucleus and a small amount of cytoplasm. Cystogenic gland cells of one type containing five types of secretion bodies are permanently connected to the outer epidermis the connection, without exception, containing a single large mitochondrion so that no secretion bodies can enter the epidermis at this stage. The body wall muscles have the characters of slowly contracting fibres but those of the oral sucker are “striated” due to the regular arrangement of dense bodies across the fibres characteristic of more powerfully contracting fibres. Penetration gland cells open into a groove dorsal to the mouth. An arrangement of spines around the groove and a concentration of muscles forms an efficient penetrating apparatus for entry into the second intermediate fish host.

Further observations on Cercaria parvicaudata Stunkard and Shaw, 1931.

Previous article No AccessJournal ArticlesFURTHER OBSERVATIONS ON CERCARIA PARVICAUDATA STUNKARD AND SHAW, 1931HORACE W. STUNKARDHORACE W. STUNKARD Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Biological Bulletin Volume 99, Number 1August 1950 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.2307/1538757 Views: 15Total views on this site © 1950 Marine Biological LaboratoryPDF download Crossref reports no articles citing this article.