Community ecology of metazoan parasites of the anchovy Anchoa tricolor (Osteichthyes: Engraulidae) from the coastal zone of the State of Rio de Janeiro, Brazil.

Between October 2001 and March 2002, 103 specimens of A. tricolor from Angra dos Reis (23 degrees 01' S, 44 degrees 19' W), in the coastal zone of the State of Rio de Janeiro, Brazil, were analyzed in order to study their metazoan parasite infracommunities. Ten species of metazoan parasites were collected: 4 digeneans, 1 cestode, 1 acantocephalan, 2 nematodes, 1 copepod, and 1 hirudinean; 77.7% of the fishes were parasitized by one or more metazoan, with a mean of 3.5 +/- 6.2 parasite/fish. Digenean was the most dominant with 4 species that accounted for 53.2% of the total parasites collected; Ergasilus sp. was the most abundant species. Abundance and prevalence of Parahemiurus merus (Linton, 1910) were positively correlated with the total length of host. Relationships between total body length of fish and both total parasite abundance and mean parasite species richness were observed. Mean parasite diversity of species was correlated to host's total length, with significant differences found between male and female fishes. Two pairs of larval species showed significant positive association and covariation. The metazoan parasite infracommunities of A. tricolor presented dominance of larval endoparasites; correlation of parasite abundance, diversity, and species richness with host total length; and low number of parasite interspecific relationships. The parasite community of A. tricolor showed some similarities with the parasite community of another South American Atlantic engraulid.     

Spatial and temporal predictability of the parasite community structure of a benthic marine fish along its distributional range

The search for consistent patterns of organisation in parasite communities remains a central theme in parasite community ecology. However, to date, much evidence comes from studies without replication in both space and time; when replicate communities are examined, repeatable patterns are rarely observed. Here we determine, using nested subset analyses, whether the infracommunities of ectoparasites and endoparasites of a benthic marine fish (Sebastes capensis) show non-random structure. Then we examine the spatial repeatability of parasite community structure across the host's distribution in the southern Pacific, and the temporal repeatability of ectoparasite community structure from one locality. In total, 537 fish were captured from different latitudes (between 11 degrees S and 52 degrees S) along the Pacific coast of South America; a further 122 specimens were captured in two other years from one of the sampling localities, Valdivia (40 degrees S). In spite of variation in fish sizes among samples, fish size generally did not correlate with either ecto- or endoparasite species richness. The ecto- and endoparasite species richness of the component communities were also not correlated with fish sample size across the nine localities. Significant nested patterns were found in the ectoparasite communities of S. capensis at all eight localities, except at latitude 52 degrees S. Significant nested patterns were also found in the endoparasite infracommunities of S. capensis at seven of the nine localities, the exceptions being those from latitudes 11 degrees S and 20 degrees S. On a temporal scale, significant nestedness was observed in the ectoparasite infracommunities of S. capensis during each of the 3 years of sampling at Valdivia. In general, the same parasite species are responsible for the repeatability of nested patterns, though their importance varies among localities. The spatial and temporal predictability of the parasite community structure in S. capensis may be associated with the fish's benthic habitat and territorial behavior, suggesting that host biology may be a key determinant of the structure of parasite communities.     

Community ecology of the metazoan parasites of namorado sandperches, Pseudopercis numida Miranda-Ribeiro, 1903 and P. semifasciata Cuvier, 1829 (Perciformes: Pinguipedidae), from the coastal zone of the State of Rio de Janeiro, Brazil

One hundred and twenty-eight specimens of namorado sandperches, 62 P. numida and 66 P. semifasciata, collected between October 2002 and June 2003 off the Cabo Frio, Rio de Janeiro, Brazil (Lat 23 degrees S and Long 42 degrees W), were examined to study their metazoan parasites. Parasite communities of these fish were composed basically of endoparasites, mainly digenean and cestodes species, with low prevalence and abundance but having high parasite species richness values (at the component community level). Among these values, that found for P. numida is the highest so far recorded for marine fishes from the Neotropical Region. Thirty-nine species of metazoan parasites were collected: 36 from P. numida and 28 from P. semifasciata. Twenty-five parasite species were common to both species of namorado sandperches. Pseudopercis numida and P. semifasciata are new host records for all parasite species collected, with the exception of Microcotyle pseudopercis. Choanodera sp., Leurodera decora, Neolebouria georgenascimentoi, and Proctoeces sp. which were recorded for the first time in the South American Atlantic Ocean. Gnathia sp. from P. numida and Scolex pleuronectis from P. semifasciata were the species having the greatest dominance frequency. Parasite abundance in P. numida and P. semifasciata were positively correlated with the host total length. Only in P. numida was parasite species richness correlated positively with the host total length. No significant differences between endoparasite infracommunities of P. numida and P. semifasciata were detected. The ectoparasites of P. numida had higher values for parasite abundance, parasite richness, Brillouin index, evenness index, and Berger-Parker index than those of the ectoparasites of P. semifasciata. Comparisons among all ecto- and endoparasites showed the ectoparasites of P. numida as the most heterogeneous group. Low similarity values were observed among the three types of parasite infracommunities of the two hosts.     

Patterns of diversity and abundance of fleas and mites in the Neotropics: host‐related,parasite‐related and environment‐related factors

The effects of host‐related, parasite‐related and environmental factors on the diversity and abundance of two ectoparasite taxa, fleas (Insecta: Siphonaptera) and mites (Acari: Mesostigmata), parasitic on small mammals (rodents and marsupials), were studied in different localities across Brazil. A stronger effect of host‐related factors on flea than on mite assemblages, and a stronger effect of environmental factors on mite than on flea assemblages were predicted. In addition, the effects of parasite‐related factors on flea and mite diversity and abundance were predicted to manifest mainly at the scale of infracommunities, whereas the effects of host‐related and environmental factors were predicted to manifest mainly at the scale of component and compound communities. This study found that, in general, diversity and abundance of flea and mite assemblages at two lower hierarchical levels (infracommunities and component communities) were affected by host‐related, parasite‐related and environmental factors, and compound communities were affected mainly by host‐related and environmental factors. The effects of factors differed between fleas and mites: in fleas, community structure and abundance depended on host diversity to a greater extent than in mites. In addition, the effects of factors differed among parasite assemblages harboured by different host species.     

Cestode communities in non-breeding populations of four grebe species (Aves: Podicipedidae) from the Bulgarian Black Sea coast.

Cestode communities in Podiceps cristatus, P. grisegena, P. nigricollis and Tachybaptus ruficollis during their migrations and overwintering are studied at the Bulgarian Black Sea coast. The infracommunities exhibit high richness, abundance and dominance, and low diversity and similarity. The component communities have a similar taxonomic structure at the levels higher than species, a small number of core species and a high portion of grebe specialists in the richness and abundance. The comparison with cestode communities in grebes from Canada (Stock & Holmes, 1987) reveals several differences and similarities. The higher richness and abundance of the infracommunities in Canada are explained by the constant conditions of breeding habitats enhancing higher transmission rates. At the component community level, there is a significant difference between the two species lists. The degree of parasite exchange among the grebe species in Bulgaria is lower. Several characters of cestode component communities in grebes do not depend on either historical factors or different habitats. These are the similar patterns of the taxonomic structure at the levels higher than species, almost the same list of generalists, the participation of specialists of anatids, and the leading role of grebe specialists in the structure.     

长江中下游三个湖泊中鳜消化道寄生蠕虫群落的组成与多样性

鱼类在食物网中的营养位置对其消化道寄生蠕虫的群落结构有重要作用。本研究调查了梁子湖、洞庭湖、鄱阳湖中鳜(Siniperca chuatsi)消化道寄生蠕虫群落的组成和多样性。在3个湖泊中共发现11种寄生蠕虫, 优势种均为范尼道佛吸虫(Dollfustrema vaneyi), 频率分布中感染有12种寄生虫的样本占65%, 单个样本中最大物种数为6。3个湖泊中平均物种丰富度为1.532.13, Brillouin多样性指数为0.120.33, 其中鄱阳湖中的多样性最高。梁子湖和洞庭湖之间的Jaccard相似度和百分比相似指数最高。通过比较食物网中不同营养位置鱼类的消化道寄生蠕虫群落结构, 发现鳜的消化道寄生虫群落的物种丰富度与多样性水平都高于植食性和杂食性鱼类。研究还讨论了宿主食物组成对消化道寄生蠕虫群落结构的影响。       

The parasitic communities of the minnow (Phoxinus phoxinus L>)

Phoxinus phoxinus being a widely distributed through Palaearctic and ecologically specialised species is a good model to study parasite communities. 72 specimens of P. phoxinus from 5 localities of the Siberia and Mongolia has been studied by the author and 651 specimens--from 5 localities in Kola Peninsula by the other researches. 595 specimens were studied by B. S. Shulman (1983) year around. To describe infra- and component parasite communities the Brillouin, Shannon, Berger-Parker indexes were used. Communities within individual fish were compared within, and between localities with quantitative percentage similarity index (Esch e. a., 1988). The Brillouin, Shannon and Berger-Parker indexes can be calculated based on abundance or total number of parasites of each species for component or compound communities. Intensity cannot be used. Significant negative correlation was observed between the Brillouin and Berger-Parker dominance indexes (r = -0.984, p < 0.01, n = 66) in infracommunities. The Brillouin index was significant positive correlated with the number of parasites in infracommunity (r = 0.407, p < 0.01, n = 66) and with the number of species in infracommunity (r = 0.92, p < 0.01, n = 66). Berger-Parker dominance index was significant negative correlated with the number of parasite in infacommunity (r = -0.815, p < 0.01, n = 66) and with the number of species in infracommunity (r = -0.268, p < 0.05). Total number of parasites and the number of species in infracommunity was positive correlated significantly (r = 0.565, p < 0.01, n = 66). These correlations remain the same at the component community level for the Shannon/Berger-Parker indexes (r = -0.965, p < 0.01, n = 10) and total number of parasites/number of species (r = 0.789, p < 0.01, n = 10) only. Similarity index was not correlate with any other indexes and parameters. No significant correlation was found between the Brillouin, Berger-Parker indexes and geographical characters of localities (longitude, latitude, altitude above sea-level). Weak correlation (r = 0.551, p < 0.098, n = 10) was observed only between the Berger-Parker dominance index and the latitude. 37 metazoan parasites have been found in all localities (specialists--40%, allogenic species--22%, rare species--40%). Allogenic generalist species of the genus Diplostomum (D. phoxini in most cases) were dominant in 60% of the component communities and 36% of infracommunities on average. 20% of the component communities were dominant by autogenic specialists Gyrodactylus magnificus and only 12% of the infracommunities were dominated by this species. Trematode and nematode larvae were core species in most localities. Frequency distribution of infracommunity richness varied from locality to locality being overdispersed in combine sample. Parasite communities at least on the infracommunity level demonstrate high variability of all parameters. Some tendency to decrease the diversity seems to be present depending on remoteness from prospective centre of origin of the genus Phoxinus.     

Dynamics of parasite communities in an age series of Baikal omul Coregonus migratorius (Georgi, 1775)

Parasite communities of Baikal omul from Chivyrkuiskii Bay of Lake Baikal have been analyzed at levels of a host individual (infracommunity), a separate age group of a host (set of infracommunities), and a host population (component community). Significant positive correlations of parameters of species richness (number of parasite species, Margalef and Menhinick indices) with the age of Baikal omul were recorded only at the level of parasite infracommunities. The absence of linear positive correlations between the parameters of species richness and the age of Baikal omul at the level of sets of parasite infracommunities were revealed for the first time for fishes of Lake Baikal. The peculiarity of the dynamics of parasite communities of Baikal omul is determined by specific features of the host physiology and ecology, primarily by the age dynamics of the feeding spectrum.     

Aggregation and species coexistence of ectoparasites of marine fishes.

Interspecific interaction may lead to species exclusion but there are several ways in which species can coexist. One way is by reducing the overall intensity of competition via aggregated utilisation of fragmented resources. Known as the 'aggregation model of coexistence', this system assumes saturation and an equilibrium number of species per community. In this study we tested the effects of interspecific aggregation on the level of intraspecific aggregation among ectoparasites of marine fishes (36 communities of gill and head ectoparasite species). If parasite species are distributed in a way that interspecific aggregation is reduced relative to intraspecific aggregation then species coexistence is facilitated. We found a positive relationship between parasite species richness and fish body size, controlling for host phylogeny. A positive relationship between infracommunity species richness and total parasite species richness was also found, providing no evidence for saturation. This result supports the view that infracommunities of parasites are not saturated by local parasite residents. The observed lack of saturation implies that we are far from a full exploitation of the fish resource by parasites. Ectoparasites were aggregated at both population and species levels. However, only half of the ectoparasite communities were dominated by negative interspecific aggregation. We found that infracommunity parasite species richness was positively correlated with the level of intraspecific aggregation versus interspecific aggregation. This means that intraspecific aggregation increases compared with interspecific aggregation when total parasite species richness increases, controlling fish size and phylogeny. This supports one assumption of the 'aggregation model of coexistence', which predicts that interspecific interactions are reduced relative to intraspecific interactions, facilitating species coexistence.     

Parasite fauna and food contents of Notothenia c.f. angustata Hutton, 1875 (Pisces: Nototheniidae) from two intertidal localities of the Arauco Gulf,Chile

We studied the parasite fauna and food contents of 38 juvenile of Notothenia c.f. angustata specimens captured in the intertidal of Island Santa María and Maule, in the Arauco Gulf, Chile. Trophic habits of Notothenia c.f. angustata were not different between localities, which was mainly algae. A total 11 parasitic taxa among were found with the digenean Lecitasther macrocotyle, cestode larvae Tetraphyllidea and Diphyllidea and nematode Ascarophis sp. being the dominant taxa. The abundance of parasites was similar in the two localities, although the infracommunity richness was higher in fish from Maule. The most abundant parasite was L. macrocotyle in hosts from Isla Santa María, while those from Maule they were the Diphyllidea larvae and nematodes Ascarophis sp. The body length of the hosts was not a good predictor of the variations in abundance and richness at infracommunities, probably because of the early ontogenetic stage of fishes.     

Patterns of infracommunity species richness in eels, Anguilla anguilla

Between October 1999 and October 2001, a total of 510 European eels Anguilla anguilla were captured in 13 different samples from the rivers Thames (five locations) and Test (one location) in southern England. The relationship between parasite component community species richness (CCR) and maximum infracommunity species richness (ICRmax) compared with that previously observed in bird and mammal hosts. Specifically, the maximum number of parasite species occurring in infracommunities equalled or exceeded half the number of parasite species in the component community at that time, across a wide range of CCR values (2-9 parasite species). Furthermore, the frequency distribution of infracommunity richness (ICR) suggested that the species composition of infracommunities is probably random. These findings suggest that intestinal macroparasite infracommunities in eels are unsaturated and potentially species rich assemblages and, in these respects, share a fundamental similarity with the infracommunities of birds and mammals.     

Ectoparasite community structure on three closely related seabird hosts: a multiscale approach combining ecological and genetic data

Parasite communities can be structured at different spatial scales depending on the level of organization of the hosts; hence, examining this structure should be a multiscale process. We investigated ectoparasite community structure in three closely related seabird hosts, the Mediterranean Cory's shearwater Calonectris diomedea diomedea , the Atlantic Cory's shearwater C. d. borealis and the Cape Verde shearwater C. edwardsii . This community was composed of three lice ( Halipeurus abnormis , Austromenopon echinatum and Saemundssonia peusi) and one flea species ( Xenopsylla gratiosa ), and was considered at the infra-, component and regional community levels. We examined temporal and spatial structuring of the infracommunities, the influence of host aggregation and body condition on the component community, and the effect of genetic and geographic connectivity among host populations on the regional community. Ectoparasite infracommunities showed substantial species overlaps in temporal patterns of abundance, but species were spatially segregated within the host body. Within component communities, all ectoparasite species showed an aggregated distribution in abundance. However, aggregation patterns and their relationships with the spatial distribution of hosts within the breeding colony differed among ectoparasite species, mainly reflecting ecological differences between fleas and lice. At the regional scale, similarity in ectoparasite communities correlated with geographic distances among host colonies, but not with genetic distances. This result suggests differences in climate and habitat characteristics among host localities as a major determinant of regional communities, rather than host connectivity. Taken together, our results highlight the importance of the geographic distribution of host breeding colonies and the spatial segregation within the host body as key factors in determining ectoparasite community structure in Calonectris shearwaters.     

Metazoan parasites of freshwater cyprinid fish ( Leuciscus cephalus): testing biogeographical hypotheses of species diversity

The diversity and similarity of parasite communities is a result of many determinants widely considered in parasite ecology. In this study, the metazoan parasite communities of 15 chub populations (Leuciscus cephalus) were sampled across a wide geographical range. Three hypotheses of biogeographical gradients in species diversity were tested: (1) latitudinal gradient, (2) a 'favourable centre' versus 'local oasis' model, and (3) decay of similarity with distance. We found that the localities in marginal zones of chub distribution showed lower parasite species richness and diversity. A latitudinal gradient, with increasing abundance of larvae of Diplostomum species, was observed. There was a general trend for a negative relationship between relative prevalence or abundance and the distance from the locality with maximum prevalence or abundance for the majority of parasite species. However, statistical support for a 'favourable centre' model was found only for total abundance of Monogenea and for larvae of Diplostomum species. The phylogenetic relatedness of host populations inferred an important role when the 'favourable centre' model was tested. Testing of the hypothesis of 'decay of similarity with geographical distance' showed that phylogenetic distance was more important as a determinant of similarity in parasite communities than geographical distance between host populations.     

Helminth parasites of the tropical gar, Atractosteus tropicus Gill, from Tabasco, Mexico

A total of 8 helminth species were recorded in an examination of 43 tropical gar, Atractosteus tropicus Gill, collected at the Pantanos de Centla Biosphere Reserve, Tabasco, Mexico. The parasite species included 1 adult trematode, 3 metacercariae, 1 cestode, 1 adult nematode, and 2 nematode larvae. Six of these 8 species were rare, with low prevalence (< 17%) and abundance (< 1.0 helminths per examined fish). The larvae of Contracaecum sp. were the most abundant in the sample, constituting 60% of the total helminths (64% prevalence, 3.8 +/- 5.2 abundance), followed by the cestode Proteocephalus singularis, constituting 18% of the worms (30.5% prevalence, 1.1 +/- 3.0 abundance). Species richness, individual parasite abundance, and diversity were low in the infracommunities. The recording of 3 specialist species in the tropical gar confirms that the helminth fauna of gar has an appreciable degree of specificity. This study indicates the importance of ecological determinants of richness in helminth communities of the tropical gar.     

The helminth community of the skink Chalcides sexlineatus from Gran Canaria (Canary Islands)

A survey of the gastrointestinal helminth communities of a population of Chalcides sexlineatus Steindachner, a small skink endemic to Gran Canaria island (Canary Archipelago, Spain), was conducted to determine the prevalence, abundance and species diversity of intestinal parasites in these reptiles. Only three parasite species were found, one cestode, Oochoristica agamae Baylis, 1919 and two nematodes, Parapharyngodon micipsae (Seurat, 1917) and Pharyngodonidae gen. sp. Helminth infracommunities of C. sexlineatus showed low values of abundance and species richness and diversity, being more similar to the helminth community of Tarentola boettgeri boettgeri (Steindachner) rather than those of Gallotia stehlini (Schenkel), both syntopic with the sampled host.     

Parasite communities of the spotted rose snapper Lutjanus guttatus (Perciformes: Lutjanidae) off the Mexican Pacific coasts: Spatial and long-term inter-annual variations

A total of 802 individuals of Lutjanus guttatus (Steindachner, 1869) specimens were collected over a 10-year period (August 2012 to February 2021) from four locations on the south-central Pacific coast of Mexico. Their parasite communities were quantified and analyzed to determine if they experience significant spatial and inter-annual variations.Thirty-two taxa of metazoan parasite were recovered and identified: four species of Digenea, four Monogenea, one Cestoda, two Acanthocephala, seven Nematoda, one Hirudinea, and nine of Crustacea (six Copepoda, and three Isopoda). Species richness was greatest among the digenean group, which represented 25% of the total species recovered, followed by the nematodes (22% of total species). Species richness at the component community level (10 to 20 species) was similar to reported richness in other Lutjanus spp. The component communities and infracommunities exhibited a similar pattern: low species richness and diversity, and dominance by a single species, mainly the monogenean Haliotrematoides guttati. Parasite community structure and species composition varied through the years, as well as between sampling locations. Variations were possibly caused by a combination of biotic and abiotic factors which generated notable changes in the infection levels of several component species. However, the similarity in the parasite species composition was high locally for short-term periods (one or two years). This result, therefore, suggests that parasite communities of L. guttatus may be more predictable locally, but only for short-term periods.     

Community structure and seasonal dynamics of helminth parasites in Lepomis cyanellus and L. macrochirus from Charlie's Pond, North Carolina: host size and species as determinants of community structure

The community structure and seasonal dynamics of 16 helminth species infecting green (Lepomis cyanellus) and bluegill (L. macrochirus) sunfishes in Charlie's Pond, North Carolina, was examined. One hundred and fifty-four fishes including 90 green sunfish and 64 bluegill sunfish were collected between March and November 2000 and examined for the presence of helminth parasites. Five of these species underwent significant changes in abundance in green sunfish infracommunities, 3 of which also displayed seasonal changes in prevalence. Three of the 16 species fluctuated seasonally in bluegill infrapopulations; 2 also underwent changes in prevalence. Species richness and diversity varied across the 9-mo period for both host species, whereas total helminth abundance remained constant. Analysis of component communities revealed differences in community structure for the 2 host species. Bluegills were found to harbor larger and more diverse communities. Bluegills also contained larger infrapopulations of 5 species, whereas green sunfish had greater abundance of 2 species. Interpretation of these data suggests that host species and size are strongly associated with the predictability of community structure.     

Ontogenetic variation in parasite infracommunities of the clingfish Sicyases sanguineus (Pisces: Gobiesocidae)

This study analyzed the variation of the parasite infracommunities and their relationship with the diet and spatial distribution of the clingfish Sicyases sanguineus during its ontogeny. In total, 154 clingfish were collected from the intertidal and the upper subtidal zone of Pacific Ocean along the central Chilean coast. A wide range in body length (1.4-34.5 cm) was observed, including juvenile and adult specimens. Eleven parasite species were found in the clingfish, i.e., 2 Copepoda, 2 Hirudinea, 1 Monogenea, 5 Digenea, and 1 Cestoda. The prevalence, total abundance, Brillouin's diversity index, and the infracommunity species richness increased with fish body length. The parasite communities, the diet, and the spatial distribution changed during clingfish ontogeny, specifically between juveniles (<20 cm body length [BL]) and adults (>20 cm BL). When fish reached a 20-cm BL, a considerable increment in abundance and species richness of parasites was observed; this coincided with an increase in the number of prey items in the diet and with a change of the fish from the intertidal into the subtidal zone. Therefore, the ontogeny of S. sanguineus is important for the variation of parasite infracommunities, which also was associated with dietary and spatial distribution shifts of this fish.