Maritrema Arenaria Research Articles

Comprehensive and Comparative Analysis of the Helminth Fauna of the Dominant Colonial Seabird Species on the Murman Coast

This work reports the results of the long-term study of the helminth fauna of the dominant colonial seabird species (common guillemots, Brunnich’s guillemots, kittiwakes, great black-backed gulls, and herring gulls) in the western, central, and eastern parts of the Murman coast. The presence of 52 parasitic worm species (18 trematode species, 21 cestode species, 11 nematode species, and 2 acanthocephalan species) was demonstrated. In the western, central, and eastern regions, the respective numbers of 32, 43, and 34 helminth species were registered. Twenty species of seabird parasites were found to be ubiquitous along the Murman coastal zone. Local foci of the trematode Maritrema arenaria and cestode Laricanthus lateralis infestation along the western part of the Murmansk coast were revealed. The highest helminth species diversity (38 species) was demonstrated for the herring gull; the lowest (7 species), for the common guillemot. Four parasite species were common for the helminth fauna of all bird species. A significant number of helminth infections were mixed ones (complexes of two or three bird species with the common helminth species in different combinations). The highest similarity of the helminth fauna was revealed in the pairs of the common guillemot and the Brunnich’s guillemot and of the great black-backed gull and the herring gull. A few parasitic worm species detected only in a single bird species were registered. The particularities and the possible causes of the geographical distribution and specificity of helminthes were analyzed, and a comprehensive assessment of the parasitological situation in the Murman coastal zone was performed.

Life history and life cycles: production and behavior of trematode cercariae in relation to host exploitation and next-host characteristics.

Life history trade-offs affect trematode parasites reproducing inside their 1st intermediate hosts. Within the constraint of the effect on host survival, parasite production of cercariae is subject to a size-numbers trade-off. Within each cercaria, resources must be partitioned between host-seeking and subsequent developmental functions. Three species of microphallid trematodes with the same 1st intermediate host (the gastropod Littorina saxatilis) were investigated. Maritrema arenaria periodically released many small cercariae. Microphallus similis released fewer, 15% larger, cercariae without periodicity. Microphallus similis cercariae were strong swimmers, moving toward the dark and downward in turbulent water, whereas Ma. arenaria cercariae remained suspended. Maritrema arenaria cercariae, although smaller in body and tail size, were produced at an average daily volume nearly twice that of M. similis. These differences are interpreted as transmission adaptations related to mobility and predictability of the 2nd intermediate host. Microphallus similis, with a mobile and less predictable crab host, adopted a 'bethedging' prolonged production of fewer cercariae by less intensive host exploitation, each cercaria having a high allocation to host-seeking behavior. Maritrema arenaria, with predictable sessile barnacle hosts, produced less mobile but potentially longer-lived cercariae in larger numbers. Microphallus piriformes metacercariae remain in the gastropod host. The number of M. piriformes metacercariae increased in larger hosts. The 3 species differed in the number of sporocysts and (meta)cercariae per sporocyst within the gastropod but not in the within-host volume of parasites. Variation in host exploitation and life history appeared adaptive for transmission to the next host.

Occurrence of Maritrema arenaria (Digenea: Microphallidae) in the acorn barnacle, Balanus perforatus (Cirripedia: Balanidae) from south-west Wales

This is the first record of the digenean parasite (Maritrema arenaria) in the acorn barnacle (Balanus perforatus). The seasonal variations in the abundance and prevalence of infection as well as variation of these with tidal level and barnacle scutum lengths are discussed.

Nucella lapillus as a paratenic host for Maritrema arenaria

Metacercariae of the microphallid trematode Maritrema arenaria are found in the shore barnacle Semibalanoides balanoides which is heavily predated by the dog whelk, Nucella lapillus. This study demonstrated that, under experimental and natural conditions, M. arenaria metacercarial cysts were ingested by N. lapillus and the metacercariae retained their viability while passing through the molluscs' digestive systems. Dog whelks are a known food source for numerous bird species, leading to the conclusion that they may act as paratenic hosts of M. arenaria. The strategic importance of the adoption by M. arenaria of N. lapillus as a paratenic host is discussed.

Nucella lapillus as a paratenic host for Maritrema arenaria

Metacercariae of the microphallid trematode Maritrema arenaria are found in the shore barnacle Semibalanoides balanoides which is heavily predated by the dog whelk, Nucella lapillus. This study demonstrated that, under experimental and natural conditions, M. arenaria metacercarial cysts were ingested by N. lapillus and the metacercariae retained their viability while passing through the molluscs' digestive systems. Dog whelks are a known food source for numerous bird species, leading to the conclusion that they may act as paratenic hosts of M. arenaria. The strategic importance of the adoption by M. arenaria of N. lapillus as a paratenic host is discussed.

The structure and formation of metacercarial cysts in the trematode family Microphallidae Travassos 1920

This study deals with the formation of the metacercarial cysts of four microphallid trematodes, Maritrema subdolum, M. arenaria, Levinseniella brachysoma and Microphallus claviformis. The first observable cyst was present around Maritrema arenaria 18 h p.i. (post-infection). The other species had not developed a cyst by day 8 p.i. but their cysts were apparent by day 16 p.i. These were bi-layered and that of M. subdolum was thicker than those of L. brachysoma and Microphallus claviformis of the same age. The structure of older cysts varied substantially between the four species. Microphallus claviformis and Maritrema subdolum cysts were fully formed at 30 days p.i. Like those of M. arenaria they were bi-layered, the outer layer (up to 3 microm thick) being electron-dense and the inner one (up to 7 microm thick) being less electron-dense. The cysts of fully formed L. brachysoma metacercariae were much more complex, composed of four layers, one of which was divisible into three sub-layers. It was concluded that the outer cyst layer was the product of secretory granules which were previously identified in cercarial tegument. The inner, thicker layer was derived from several sources. These included small tegument vesicles produced over the entire surface of the metacercariae, larger fragments of tegument released from the anterio-ventral region and material liberated from the metacercarial excretory bladder. This heterogeneous material accumulated in the cyst lumen for some time before becoming polymerized to form the thick inner layer or layers of the metacercarial cysts.

Developmental changes in the tegument of four microphallid metacercariae in their second (crustacean) intermediate hosts

AbstractThe morphology of the tegument of four microphallid metacercariae from the stage of invasive cercariae to their maturation as encysted metacercariae inside their crustacean second intermediate hosts is described. The tegument of the metacercariae developed surface lamellae and projections which, along with coated vesicles in the surface syncytium, indicated that the tegument had an absorptive function. The disappearance of secretory granules from the tegument at the same time as the appearance of the first cyst wall suggested that the tegument had a role in primary cyst production. Following this, the metacercariae continued to grow and seemingly retained their absorptive ability. The tegument was also involved in the transport of material into the perimetacercarial lumen prior to its eventual inclusion in the developing inner cyst layers. It appeared that this material originated in tegumental cells located amongst the parenchymal cells beneath the tegumental syncytial layer. On completion of the secondary cyst layers there was a gradual degeneration of structures associated with absorption and a progressive accumulation of dense discoid granules traceable to underlying tegumental cells. All four microphallid species (Maritrema arenaria,M. subdolum,Levinseniella brachysomaandMicrophallus claviformis) demonstrated the same developmental pattern but the period spent in each stage differed depending on the time spent migrating to encystment sites. The pattern of tegumental development described is thought to be applicable to all microphallid metacercariae and possibly to other metacercariae which undergo growth and development in their second intermediate hosts.

Morphological comparison of in ovo derived and naturally occurring flukes using Microphallus similis, M. pygmaeus and Maritrema arenaria

AbstractThis investigation deals with the evaluation of the in ovo technique for the cultivation of trematodes. The technique has previously been used for the maturation of digenetic flukes and the establishment of life cycles in the laboratory but it was not known if the adult flukes produced were morphologically comparable to those found in their natural hosts. Three species of microphallids, Microphallus similis, M. pygmaeus and Maritrema arenaria were used. Metacercariae of each species were inoculated into fertile hen's eggs which were incubated at 41°C for 120 hours. The adult flukes recovered were stained and mounted and morphonietric measurements obtained were compared to definitive descriptions of the three microphallid species. The results showed that the in ovo technique provided adult flukes which were indistinguishable from those occurring in natural hosts.

Identification of the cercarial stage ofMaritrema arenaria(syn.M. gratiosum) (Trematoda: Microphallidae)

Maritrema arenaria is a microphallid trematode found in the intestines of marine wading birds. The metacercarial stage occurs in barnacles, Semibalanus balanoides. To date the cercarial stage had not been identified. Large numbers of M. arenaria metacercariae were found in barnacles at one site on the north shore of Belfast Lough, N. Ireland (Irish Grid Reference D355,810) where a previously unidentified cercaria, Cercaria littorinae saxatilis V, was also abundant. Experiments were carried out to establish if C. littorinae saxatilis V developed into the metacercariae of M. arenaria. The experiments demonstrated that C. littorinae saxatilis V entered the cirri of feeding barnacles and later accumulated in the haemocoel close to the barnacle's gut. There the cercariae formed cysts which increased in size until they attained the structure of M. arenaria metacercariae. The study has clearly demonstrated that the cercariae of M. arenaria are those previously known as C. littorinae saxatilis V.

Dispersion and abundance of Maritrema arenaria in Semibalanus balanoides in north-east Ireland

ABSTRACTInfection of the barnacle Semibalanus balanoides with the digenean trematode Maritrema arenaria was investigated at 17 sites along the Co. Down coastline. There was a low background level of infection. Abundance of M. arenaria, however, was substantially greater at sites close to fish factories and at a site close to a sewage works. Aggregation of M. arenaria in S. balanoides was least marked at low mean parasite burdens. The parasitic burden was related more closely to barnacle size at a site of heavy infection than at one with a low abundance. There was a significant association between height on the shore and number of encysted metacercariae in S. balanoides. This was independent of variation in host size. It is concluded that relationships that bring about overdispersion of digeneans, such as that between the size-structure of the host population and parasite infection, may be dependent on the overall abundance of the parasite.

A Note on the Distribution of Metacercariae of Maritrema Arenaria in Balanus Balanoides at a Site on the North-East Coast of England

The survey of Balanus balanoides (L.) for metacercarial cysts of Maritrema arenaria Hadley and Castle, 1940, on the east coast of Northern Ireland by Irwin & Irwin (1980) prompted us to carry out a similar survey in the north-east of England. The site we selected was a rocky shore at Whitburn, Sunderland (Grid Ref. NZ411 613) from which six separate batches of 100 barnacles, B. balanoides, were examined. The results were as in Table 1.

The distribution of metacercariae of Maritrema arenaria (Digenea: Microphallidae) in the barnacle Balanus balanoides at three sites on the east coast of Northern Ireland

Overall incidence of metacercariae of Maritrema arenaria differed substantially at each of the three sites investigated. In each case, however, numbers were higher than those previously observed in the British Isles. Results indicate that gulls rather than waders are the more important final hosts of this parasite in the areas investigated. At one site where a more detailed survey was carried out metacercariae were more abundant on the upper half of the shore and they displayed a marked preference for barnacles on living Littorina littorea shells as compared to barnacles on rocks. Evidence would suggest that the two most likely molluscan hosts of this trematode are Littorina saxatilis and Nucella lapillus.

DESCRIPTION OF A NEW SPECIES OF MARITREMA NICOLL 1907, MARITREMA ARENARIA, WITH STUDIES OF THE LIFE HISTORY

A new species of the trematode genus Maritrema, Maritrema arenaria, is described as to morphology, adult host (Arenaria interpres), and metacercarial host (Balanus balanoides). Negative results are reported from a search for the sporocyst and cercarial stages of this fluke, and the suggestion is made that the cercaria may not be present during the summer months in the Woods Hole region.