Metazoan Parasite Communities Research Articles

Patterns in metazoan parasite communities of some oyster species

Metazoan parasite communities of Crassostrea gigas and Ostrea edulis from Great Britain, Crassostrea virginica from Mexico, and Saccostrea commercialis from Australia are described and summarized in terms of species composition, species richness, total number of individuals and dominance. Metazoan parasite communities in all host species were composed of turbellarians and the metacercarial stage of digeneans, with the exception of S. commercialis where only metacercariae were found. Arthropods, including one copepod and one mite species, were present only in British oyster species. All metazoan parasite communities of oysters had few species and low density of individuals. Richest communities were found in C. virginica at both component and infracommunity level. The least diverse component community occurred in S. commercialis. Infracommunities in O. edulis and S. commercialis never exceeded one species per host. The host response against parasites is suggested as the principal factor responsible for depauperate parasite communities of oysters. Environmental factors characteristic of tropical latitudes are likely to have enhanced both the number of species and the densities of parasites per host in the infracommunities of C. virginica.

Patterns in metazoan parasite communities of some oyster species

Metazoan parasite communities of Crassostrea gigas and Ostrea edulis from Great Britain, Crassostrea virginica from Mexico, and Saccostrea commercialis from Australia are described and summarized in terms of species composition, species richness, total number of individuals and dominance. Metazoan parasite communities in all host species were composed of turbellarians and the metacercarial stage of digeneans, with the exception of S. commercialis where only metacercariae were found. Arthropods, including one copepod and one mite species, were present only in British oyster species. All metazoan parasite communities of oysters had few species and low density of individuals. Richest communities were found in C. virginica at both component and infracommunity level. The least diverse component community occurred in S. commercialis. Infracommunities in O. edulis and S. commercialis never exceeded one species per host. The host response against parasites is suggested as the principal factor responsible for depauperate parasite communities of oysters. Environmental factors characteristic of tropical latitudes are likely to have enhanced both the number of species and the densities of parasites per host in the infracommunities of C. virginica.

Diversity of metazoan parasites of the introduced oyster species Crassostrea gigas in the Exe Estuary

Temporal patterns in metazoan parasite community diversity of Crassostrea gigas, (Lamellibranchia: Ostreidae) were studied in the Exe Estuary at monthly intervals over one year and in relation to host age-classes. A total of four metazoan species was found to parasitize C. gigas in the Exe Estuary: the turbellarian Paravortex sp., cercaria Lepocreadiidae, metacercariae of Renicola roscovita and the copepod Mytilicola intestinalis. Only R. roscovita and M. intestinalis were present in all months throughout the year and in all host age-classes. Analysis of the metazoan parasite community at individual host level revealed little variation in community structure with respect to season or host age, as only a slight increase in diversity values was observed during the summer months. However, community diversity does vary from year to year, as shown by comparison between host age group samples in three consecutive years. None of the parasites are specialist to oysters but all appear to be widespread and abundant parasite of other lamellibranch species.

Metazoan parasite community structure in brown trout from two lakes in western Ireland.

A total of 549 brown trout were caught from two lakes, Lough Feeagh and Bunaveela Lake, in the Burrishoole system, Co. Mayo, Ireland. Seven species of metazoan parasite were detected but only four species occurred in > or = 10% of the sample. The parasite community of the trout was dominated by a single species, Pomphorhynchus laevis, with a prevalence if 58%. Only one allogenic helminth species was recorded from the trout, Diphyllobothrium ditremum, with the community mainly comprising autogenic species. Few differences were found between the two lakes, although the larger lake, Lough Feeagh, did contain some trout which harboured more parasite species and had, on average, fish with higher numbers of individual parasites. Measures of species richness and diversity were very low, indicating an impoverished helminth community with little potential for interspecific interactions. Host age was found to significantly influence these indices of infracommunity structure.

The Metazoan Parasite Community of Migrating Greater Yellowlegs, Tringa melanoleuca, from the Rio Grande Valley, Texas and New Mexico

Forty-eight migrant greater yellowlegs, Tringa melanoleuca, collected from southwestern Texas and southeastern New Mexico were examined for metazoan parasites. Nine helminth and 7 ectoparasite species were collected. Five new host records were recorded. The helminth fauna showed little diversity, little concentration for dominance, and no significant positive or negative associations between species were found. All species of helminths showed a contagious distribution. The component helminth community consisted of 2 core, 3 secondary, and 4 satellite species, and there was no host specialist. A checklist of metazoan parasites reported from greater yellowlegs in North America is included.

Metazoan parasite communities of yellow eels (Anguilla rostrata) in acidic and limed rivers of Nova Scotia

Metazoan parasite communities of 269 yellow eels (Anguilla rostrata) inhabiting acidic (pH 4.5–5.0) and deacidified (limed to a pH of 6.0–7.0) portions of a watershed in southwest Nova Scotia were compared over 3 years. Paraquimperia tenerrima, Ergasilus celestis, Bothriocephalus claviceps, Proteocephalus macrocephalus, Crepidostomum brevivitellum, and Azygia longa were found. Species richness was greater and there were more multiple infections in the component community in eels from the limed portion of the watershed than in the community in the acidic river. Differential susceptibility of the parasites or their intermediate hosts to acidification appears to be involved in structuring the community. Digeneans were absent from eels in the acidic river. The copepod E. celestis occurred throughout the watershed but was less common in the acidic river. The occurrences of two species, B. claviceps, and P. macrocephalus, were similar at acidified and limed sites. Numbers of infected fish and prevalence of the dominant parasite, P. tenerrima, were highly variable in eels from the acidic region, but were relatively stable at the limed site. It is concluded that the assemblage of metazoan parasites of fish may be useful as environmental indicators, and may also provide information on the dynamics of altered food webs.

Are eels (Anguilla anguilla L.) planktonic feeders? Evidence from parasite communities

The metazoan parasite communities of eels Anguilla anguilla were investigated in three riverine localities and one lake in Devon. Altogether 21 species of parasite, the majority of the British eel parasite fauna, were recorded. Parasite communities in the three riverine localities were more similar to each other than to that of the lake. The four parasite component communities were typical and representative of those from eels in other parts of the U.K. They were characterized by low species diversity and domination by a single species: Pseudodacytlogyrus anguillae in the rivers and Diplostomum spathaceum in the lake. Both the dominant species and the majority of parasite species, and hence individuals, in any locality infected eels directly by free swimming planktonic larval stages or indirectly by the ingestion of infected planktonic copepod intermediate hosts. Examination of other species of fish in each locality showed that only Raphidascaris acus utilized a fish species as an intermediate or paratenic host to infect eels. Increases in prevalence and intensity of infection with size of eel by helminths such as Camallanus lacustris and Paraquimperia tenerrima were observed in localities in which transmission of these parasites could not have involved another fish species. Over 63% of the specialist, specific parasites of eels throughout Europe employ planktonic transmission to their hosts, as do several species of the commoner generalists. A study of eel parasite communities thus leads to the conclusion that eels are widely and closely associated in their habits with plankton and that eels of all sizes feed regularly upon planktonic copepods: the widely accepted view of eels as being more or less exclusively benthic in habit and feeding behaviour requires re‐appraisal.

Metazoan Parasite Community Composition and Structure of Migrating Wilson's Phalarope, Steganopus tricolor Viellot, 1819 (Aves), from El Paso County, Texas

Metazoan Parasite Community Composition and Structure of Migrating Wilson's Phalarope, Steganopus tricolor Viellot, 1819 (Aves), from El Paso County, Texas

Population sizes of metazoan parasites of brook trout (Salvelinus fontinalis) and Atlantic salmon (Salmo salar) in a small Newfoundland lake

The metazoan parasite community of fishes (Salvelinus fontinalis, Salmo salar, Gasterosteus aculeatus) in a small lake in central Newfoundland, Canada, was studied. It consisted of three components: parasites of salmonids (Salmincola spp., Discocotyle sagittata, Apophallus imperator, Diplostomum sp., Tetracotyle sp. 1, Cystidicoloides tenuissima, Eubothrium salvelini, Diphyllobothrium sp., glochidia), parasites of sticklebacks (Gyrodactylus avalonia, Tetracotyle sp. 2, Shistocephalus solidus), and parasites shared by salmonids and sticklebacks (Ergasilus sp., Metechinorhynchus lateralis, Crepidostomum farionis). Population estimates were made of the salmonid fishes by the Schnabel mark–recapture method. By multiplying infection prevalence × intensity × number of fish, population estimates were obtained for each species of salmonid parasite. This information revealed that S. fontinalis carries almost all of the salmonid parasite populations and that the seaward migration of S. salar at 2–5 years of age is an insignificant loss to the parasite community. It also revealed that the majority of the population of C. tenuissima, M. lateralis, and Ergasilus sp. is carried by the more abundant small fishes, while the majority of the population of D. sagittata, A. imperator, Tetracotyle sp. 1, and S. edwardsii is carried by the less abundant large hosts. Possible reasons for these two distributions are discussed.