Component Community Structure Research Articles

Structure of compound and component communities of fleas parasitic on small mammals in six different regions as revealed by environmental‐based co‐occurrence geometry analyses

AbstractWe inferred the patterns of co‐occurrence of flea species in compound (across all host species) and component (across conspecific hosts) communities from six regions of the world (Mongolia, Northwest Argentina, Argentinian Patagonia, West Siberia, Slovakia, and South Africa) using the novel eigenvector ellipsoid method. This method allows us to infer structural community patterns by comparing species’ environmental requirements with the pattern of their co‐occurrences. We asked whether: (a) communities are characterized by species segregation, nestedness, or modularity; (b) patterns detected by the novel method conform to the patterns identified by traditional methods that search for non‐randomness in community structure; and (c) the pattern of flea species co‐occurrences in component communities is associated with host species traits. The results of the application of the eigenvector ellipsoid method suggested that the co‐occurrence of flea species was random in all compound communities except in South Africa, where this community demonstrated a tendency to be nested. Flea species co‐occurrences were random in many component communities. Species segregation was detected in the flea community of one host, whereas the flea communities of 14 hosts from different regions appeared to be nested. No indication of a modular structure in any community was found. The nestedness of flea component communities was mainly characteristic of hosts with a low relative brain mass. We concluded that the application of this novel method that combines data on species distribution and their environmental requirements allows better identification of the community structural patterns and produces more reliable results as compared with traditional methods.

Metazoan parasites in Colomesus asellus (Pisces: Tetraodontidae) from Amazon River, in Brazil: an ecological, annual and seasonal study

ABSTRACT Our hypothesis is that annual and seasonal variations influence the structure of component communities and diversity of metazoan parasites from Colomesus asellus from the Amazon River. A total of 107 fish were collected during 2020 and 2021, and 932 metazoan parasites were recovered. In 2020, four species of parasites (one Nematoda, two Digenea and one Crustacea) were found; and in 2021, five species (one Nematoda, one Digenea, one Acanthocephala and two Crustacea) were recorded. Ergasilus colomesus was the most dominant throughout the study. Species richness and Brillouin diversity index were higher in 2021 and in the dry season. Some parasite component communities showed differences between years and between seasonal periods. The structure of parasite communities was mainly influenced by rainfall levels, seasonal availability of infective stages in the environment, and body size of the fish host. These facts corroborate the hypothesis that such variables could influence the component communities of parasites. Lastly, this is the first record of Contracaecum sp., Genarchella genarchella, Clinostomum marginatum, Brasacanthus sp. and Argulus pestifer in C. asellus.

Long-term study reveals central European aerial insectivores as an unusual group of hosts that harbor mostly helminths that are unable to complete life-cycles in the nesting quarters of their hosts

BackgroundCentral European aerial insectivores are long-distance migrants that winter in sub-Saharan Africa. Most of them employ the fly-and-forage migrating strategy and differ in their food composition. The composition and structure of helminth component communities of these hosts are poorly understood, and information regarding seasonality and long-term changes is unavailable.MethodsFrom 1963 to 2022, we analyzed the population trends of helminths in five aerial insectivore species. Namely, we examined Apus apus, Hirundo rustica, Delichon urbicum, Riparia riparia, and Ficedula albicollis; all originated from the Czech Republic.ResultsWe identified central European aerial insectivores as hosts that are parasitized mostly by helminths that cannot complete their life-cycles in the nesting quarters of their hosts. This phenomenon is unknown in other bird host species. In contrast, only a single dominant trematode species that completes its life-cycle locally colonized the central European aerial insectivores. All other dominant species of Trematoda, all Nematoda, and all Acanthocephala were dependent on intermediate hosts unavailable in the nesting quarters of the examined bird hosts. Surprisingly, these helminths transmitted from winter quarters or migratory routes were diverse, and many of them were abundant in terms of both prevalence and intensity of infection. The helminth component communities of aerial insectivores were dynamic systems. During the study period, three species became new and regularly encountered members of helminth fauna of examined hosts, and other species gradually increased or decreased their intensity of infection. In contrast to other groups of bird hosts, the dominant helminth species of aerial insectivores did not experience local extinctions or rapid population losses.ConclusionsThe analysis of helminths of five central European aerial insectivores revealed component communities that heavily rely on completing host–parasite cycles at migration routes or wintering grounds. The composition of the analyzed component communities changed dynamically during the 60-year-long study period, but there was no evidence of large-scale declines in abundance or prevalence.Graphical

Insect herbivory immediately before the eclipse of the gymnosperms: The Dawangzhangzi plant assemblage of Northeastern China

The Early Cretaceous terrestrial revolution involved global shifts from gymnosperm- to angiosperm-dominated floras. However, responses of insect herbivores to these changes remain unexamined. We evaluated 2176 highly sampled plant specimens representing 62 species/morphotypes from the 126Ma Dawangzhangzi plant assemblage of Northeastern China. Our study consisted of horsetails, ferns, ginkgoaleans, czekanowskialeans, conifers, and an angiosperm. Their herbivory was evaluated by the functional feeding groups of hole feeding, margin feeding, and surface feeding (ectophytic feeders); piercer and suckers, and ovipositing insects (ectoendophytic feeders); mining, galling, and borings (endophytic feeders); and pathogens, collectively constituting 65 damage types (DTs). The plant assemblage was assessed for herbivory richness by DT richness, component community structure, and DT specialization on plant hosts; for herbivory intensity, it was evaluated for DT frequency, herbivorized surface area, and feeding event occurrences. Using feeding event occurrences, the data supported seven species/morphotypes as most intensely herbivorized: Liaoningocladus boii (76.6%), Czekanowskia sp. 1 (8.4%), Czekanowskia rigida (4.10%), Lindleycladus lanceolatus (3.5%), Ginkgoites sp. 2 (2.0%), Podozamites sp. 1 (1.1%), and Solenites sp. 1 (0.9%). The most herbivorized taxa were pinaleans (conifers), then czekanowskialeans, and lastly ginkgoaleans; the monodominant component community was the conifer Liaoningocladus boii. DT host specialization levels were low. The plant assemblage had an overall low 0.86% of foliage removed by herbivores, explained by physical and chemical antiherbivore defenses, and parasitoid attack. Although Paleozoic, gymnosperm-dominated assemblages had greater herbivory, component community structure of the three most herbivorized taxa are more similar to modern bracken fern and willow than modern gymnosperm taxa.

Helminth communities of Coregonus lavaretus (Salmonidae: Coregoninae) from Lake Kamennoye (Kostomuksha State Nature Reserve, Russia)

Macroecological models are useful for assessing trends in variability for developing monitoring strategies of successional changes and anthropogenic transformation of aquatic ecosystems. Modelling of the relationships of the generalised population indices also makes possible to reveal qualitative differences in the structure of parasite component communities. We analysed helminth communities of Coregonus lavaretus from a natural water body, Lake Kamennoye (Kostomuksha State Nature Reserve, Russia). The component community of metazoan parasites of C. lavaretus was represented by nine helminth species. Infection with cestodes (two species), nematodes (three species), and trematodes (one species) reflects the presence of zooplankton, aquatic insects and molluscs in the diet of fish, while infection with trematode larvae (three species) occurs by percutaneous penetration. The complete ITS1-5.8S-ITS2 cluster of the rRNA gene was sequenced in order to identify trematode larvae. Metacercariae of Diplostomum sp. LIN 5 were the most abundant among them. Using populational approaches, we described the species richness and the diversity of infra- and component communities of the parasites. We also described the species composition and the structure of the component community, the distribution and the accumulation rate of species richness, and the relationships between the infection intensity and the prevalence. Five species (Diplostomum sp. LIN5, Tylodelphys immer, Crepidostomum farionis, Proteocephalus longicollis, and Raphidascaris acus) were considered as the core species of the component community, while other helminths were considered as satellite species. We conclude that infra-communities play a key role in the formation of species richness, structure and abundance of the parasitic component community of C. lavaretus. Infra-communities in younger age groups of C. lavaretus are characterised by the paucity and a relatively high diversity of the species composition of parasites, which is probably a consequence of their diverse diet. In older fish, the species richness of infra-communities increases but the species diversity of the parasites declines, indicating a pronounced dietary specialisation. An analysis of species richness and population characteristics indicates that in Lake Kamennoye, the parasite communities of C. lavaretus are fairly stable, which reflects the stability of the entire lake ecosystem.

Temporal and seasonal variations in parasites of Metynnis lippincottianus (Characiformes: Characidae), a host from the eastern Amazon (Brazil)

ABSTRACTThis study investigated the influence of temporal and seasonal variation (rainy/dry cycle) on the component community structure and infracommunities of parasites in Metynnis lippincottianus from the eastern Amazon (Brazil). A total of 8,774 parasites representing 9 species and 22,765 parasites representing 12 species was collected in 2011 and 2016 respectively, but only 42.8% of the species were common to both study years. In both years, there was a dominance of Ichthyophthirius multifiliis and the component community was 51% dissimilar. The species richness of parasites and the Berger–Parker dominance were higher in 2016, while the evenness and Brillouin diversity were higher in 2011. The prevalence and abundance of I. multifiliis and P. pillulare, as well as the prevalence of Contracaecum sp. were higher in the rainy season. The abundance of Anacanthorus strongylophalus, Urocleidoides sp., Dadayus pacupeva and Dadaytrema oxycephala was higher in the dry season. Infection with Procamallanus (Spirocamallanus) inopinatus was not influenced by the season, while by Trichodina sp. occurred only in the dry season and Ergasilus xinguensis only in the rainy season. The species richness of parasites, Brillouin diversity index and evenness were higher in the dry season, while the Berger–Parker index was higher in the rainy season. Temporal variation of communities and infracommunities of parasites was influenced by the body size of host populations and increase in anthropogenic impacts. Effect of seasons on environmental quality, host size and availability of infective stages of parasites were the determining factors in structuring the component communities and infracommunities of parasites.

Parasites as indicators of fish population structure at two different geographical scales in contrasting coastal environments of the south-western Atlantic

Fish parasites are widely used as biological tags of stocks and populations of their hosts at large spatial scales, but less frequently at small geographical scales. The application of this methodology at small scales requires heterogeneity in the availability of infective stages of parasites and hosts with high site fidelity. Here we tested the value of parasite tags at both large and small spatial scales using the Argentine silverside, Odontesthes argentinensis (Valenciennes, 1835) as a model. This is a marine fish that can tolerate a wide range of salinities and has great phenotypic plasticity, which has promoted adaptive divergences at reduced spatial scales across populations, in the absence of geographical barriers isolating them, which could be reflected in their parasite assemblages. A total of 142 specimens were examined for parasites. Samples were collected at two close localities from each of two different biogeographical regions of the south-western Atlantic. The structure and composition of both parasite infracommunities and component communities were analysed through uni and multivariate statistics. All sites were significantly different in their infracommunity structure, even those that were at shorter distances from each other. However, infracommunity composition and component community structure showed higher similarities within each region than between samples from different ones. These results proved that fish parasites are valuable tools to assess fine-scale population structure of their hosts when site fidelity and adaptations to local conditions prevail. The inclusion of parasite indicators as complementary tools in such kind of studies can provide valuable evidence for those resources requiring stock assessments and management at fine-scale, in order to prevent negative impacts over exploited populations.

Species composition and structure of parasites component communities of tugun <i>Coregonus tugun</i> (Pallas, 1814) from the Khatanga and Yenisei Rivers

Tugun Coregonus tugun (Pallas, 1814) is an endemic of Siberia. Information about the species composition and structure of tugun parasite community on the stage of spawning migration is described in this paper. We carried out ichtioparasitologic studies in the Yenisey and the Khatanga Rivers in 20112014. Tugun parasite complex from the Khatanga River remains statistically identical in species composition, number of individuals and biomass and differs from those of the Yeniseis tugun over the entire study period. Apparently two different stocks of tugun were investigated in the Yenisei River. One of them lives in the Yeniseis streambed, the other one lives in the Podkamennaya Tunguska River. The composition of the parasitic fauna of tugun from two rivers is formed by generalist species. Tugun parasites component communities from all material collection stations have high values of the Shannon index and two dominant species (by numbers of parasites and by biomass). We found out that the species biomasses differ significantly on the graphic community structure. The description of tugun parasite communities corresponds to characteristic of a climax community on the stage of destruction except the graphic structure. In the analyzed parasitic communities the processes of egg laying and larval appearance, the death of parasites of previous year generation and infection with this year parasites occur simultaneously. The stages of formation and destruction of the community overlap. The described state of tugun parasites communities has an adaptive value. The load on the host body is reduced which ensures the long-term existence of parasites.

Metazoan Parasites and Health State of European Eel, Anguilla Anguilla (Anguilliformes, Anguillidae), From Tonga Lake and El Mellah Lagoon in the Northeast of Algeria

Abstract The aim of the study was to examine metazoans parasite communities of European eels (Anguilla anguilla) in freshwater (Tonga Lake) and brackish water (El Mellah lagoon) in the northeast of Algeria. Six parasite taxa were collected: one monogenean, Pseudodactylogyrus sp.; two crustaceans, Ergasilus sp. and Argulus foliaceus; two nematodes, Cucullanus sp. and Anguillicola crassus; one cestode, Bothriocephalus claviceps. Th e most prevalent parasite taxa in freshwater were Pseudodactylogyrus sp., A. crassus and Bothriocephalus claviceps; whereas in the brackish water, eels were infected mainly with A. crassus. Th e characteristics of the parasite component community structure revealed low parasite species diversity and high dominance values in eels from the two localities. Both communities were dominated by a single parasite species: Tonga eels by the monogenean Pseudodactylogyrus sp. and El Mellah lagoon eels by the nematode A. crassus, verified by high Berger-Parker dominance values of 0.76 and 0.87 respectively.

Composition and Diversity of Communities of Dactylogyrus spp. In Wild and Farmed Goldfish Carassius auratus.

Species composition and diversity of dactylogyrids were compared on gills of wild and cultured goldfish (silver crucian carp) Carassius auratus from 3 naturally populated lakes and 3 stocked aquaculture ponds in the Hubei province of China to examine the differences in the gill parasite community between these natural and farmed waters. Of the 7 Dactylogyrus spp. detected, all were found in lakes and 5 in ponds, with Dactylogyrus inexpectatus and Dactylogyrus anchoratus being absent from ponds. No significant correlation was found between the species richness and habitat area or host size, nor was there a significant difference in mean species richness between lakes (0.41-0.65) and ponds (0.30-0.76). Brillouin's diversity in lakes (0.049-0.067) was higher than that in ponds (0.024-0.046), but not significantly so. Although the diversity of parasite communities was higher in wild goldfish, higher mean abundance of some Dactylogyrus spp. was found in cultured goldfish. Based on Bray-Curtis similarity, it was difficult to differentiate parasite communities in lakes from those in ponds at the infracommunity level, whereas the 3 lakes and Guanqiao pond differed markedly from the remaining 2 ponds at the component community level. Although infracommunities differed among waterbodies, no effects of fish length or waterbody type were found on infracommunity or component community structure. Together, these results suggest that abundance and species richness of Dactylogyrus spp. on goldfish in lakes and farm ponds are influenced by habitat-specific environmental factors.

Williamson Drive: Herbivory from a north-central Texas flora of latest Pennsylvanian age shows discrete component community structure, expansion of piercing and sucking, and plant counterdefenses

Insect herbivory during the Pennsylvanian–Permian transition interval (late Gzhelian) was estimated from the Williamson Drive locality of north-central Texas, USA. We investigated vegetational composition and the response of host plants to herbivores by characterization of insect-damage patterns. The bulk flora consists of four major plant groups: lycophytes, sphenophytes, pteridophytes, and pteridosperms, as well as unaffiliated morphotypes. Forty-six distinctive damage types (DTs) were recognized from 17 herbivorized plant-host taxa that were categorized into the five functional feeding groups (FFGs) of external foliage feeding (20 DTs), oviposition (11 DTs), piercing and sucking (9 DTs), galling (5 DTs), and wood boring (1 DT). The distributional patterns of FFGs and DTs on the most herbivorized plant hosts indicate several generalized and specialized patterns and organization into distinctive component communities. The overall herbivory level in the flora is elevated compared to other Cisuralian floras of north-central Texas, based on separate analyses of foliar surface area removed (0.86%) and frequency of herbivorized leaves (19.83%). One ubiquitous plant host, Macroneuropteris scheuchzeri (Hoffmann) Cleal, Shute and Zodrow, is disproportionately consumed, representing 35.75% of all specimens, but contributing 84.38% of the total herbivorized surface area, 60.87% of DT richness, and 55.44% of the DT abundance from all plant species. A notable feature is the abundance of nine piercing-and-sucking DTs on several hosts, representing three of the four new DTs described in this flora and indicating the ecological expansion of this FFG by Paleodictyopteroidea and earliest Hemipteroidea. There is evidence for physical and chemical antiherbivore defense afforded by trichomes and resin ducts of two major host plants, but the absence of seed predation is curious. Analyses of herbivory at Williamson Drive and four younger Cisuralian floras of the region support Feeny's apparency hypothesis. The overwhelming dominance of M. scheuchzeri herbivory at Williamson Drive, absent in earlier, peat-substrated Pennsylvanian floras, is typical of Cisuralian mineral-substrated plants.

Floral Assemblages and Patterns of Insect Herbivory during the Permian to Triassic of Northeastern Italy.

To discern the effect of the end-Permian (P-Tr) ecological crisis on land, interactions between plants and their insect herbivores were examined for four time intervals containing ten major floras from the Dolomites of northeastern Italy during a Permian–Triassic interval. These floras are: (i) the Kungurian Tregiovo Flora; (ii) the Wuchiapingian Bletterbach Flora; (iii) three Anisian floras; and (iv) five Ladinian floras. Derived plant–insect interactional data is based on 4242 plant specimens (1995 Permian, 2247 Triassic) allocated to 86 fossil taxa (32 Permian, 56 Triassic), representing lycophytes, sphenophytes, pteridophytes, pteridosperms, ginkgophytes, cycadophytes and coniferophytes from 37 million-year interval (23 m.yr. Permian, 14 m.yr. Triassic). Major Kungurian herbivorized plants were unaffiliated taxa and pteridosperms; later during the Wuchiapingian cycadophytes were predominantly consumed. For the Anisian, pteridosperms and cycadophytes were preferentially consumed, and subordinately pteridophytes, lycophytes and conifers. Ladinian herbivores overwhelming targeted pteridosperms and subordinately cycadophytes and conifers. Throughout the interval the percentage of insect-damaged leaves in bulk floras, as a proportion of total leaves examined, varied from 3.6% for the Kungurian (N = 464 leaves), 1.95% for the Wuchiapingian (N = 1531), 11.65% for the pooled Anisian (N = 1324), to 10.72% for the pooled Ladinian (N = 923), documenting an overall herbivory rise. The percentage of generalized consumption, equivalent to external foliage feeding, consistently exceeded the level of specialized consumption from internal feeding. Generalized damage ranged from 73.6% (Kungurian) of all feeding damage, to 79% (Wuchiapingian), 65.5% (pooled Anisian) and 73.2% (pooled Ladinian). Generalized-to-specialized ratios show minimal change through the interval, although herbivore component community structure (herbivore species feeding on a single plant-host species) increasingly was partitioned from Wuchiapingian to Ladinian. The Paleozoic plant with the richest herbivore component community, the coniferophyte Pseudovoltzia liebeana, harbored four damage types (DTs), whereas its Triassic parallel, the pteridosperm Scytophyllum bergeri housed 11 DTs, almost four times that of P. liebeana. Although generalized DTs of P. liebeana were similar to S. bergeri, there was expansion of Triassic specialized feeding types, including leaf mining. Permian–Triassic generalized herbivory remained relatively constant, but specialized herbivores more finely partitioned plant-host tissues via new feeding modes, especially in the Anisian. Insect-damaged leaf percentages for Dolomites Kungurian and Wuchiapingian floras were similar to those of lower Permian, north-central Texas, but only one-third that of southeastern Brazil. Global herbivore patterns for Early Triassic plant–insect interactions remain unknown.

Host specificity and seasonality of helminth component communities in central European grebes (Podicipediformes) and loons (Gaviiformes)

Structure and pattern of helminth component communities parasitizing grebes and loons are poorly understood. Here we analyze the prevalence, intensity and diversity of helminths in 505 Czech grebes (Podiceps cristatus, Podiceps nigricollis, Tachybaptus ruficollis) and loons (Gavia arctica, Gavia stellata) collected between 1962 and 2014. The species richness of helminth component communities ranged from 31±8 (P. cristatus) to 50±4 (G. stellata) species, with helminth load similar in all five host species, but with strong differences in prevalence and intensity of infection at a helminth species-specific level. The dominance was low, ranging from 0.11 (P. cristatus and G. stellata) to 0.21 (P. nigricollis). Dominant species (>25% prevalence) in P. cristatus were Confluaria sp., Tylodelphys clavata, Echinochasmus coaxatus, Petasiger neocomense and Ligula colymbi; in P. nigricollis and T. ruficollis: Confluaria sp. and Tatria sp.; in G. arctica and G. stellata: Tetrabothrius microcephalus, Stephanoprora denticulata, Cryptocotyle concava, Diplostomum gavium and Ichthyocotylurus erraticus; in G. stellata only: Echinochasmus (Monilifer) spinulosus. Four (12%) of the grebe digenean species were not locally acquired (with non-sympatric intermediate hosts) despite the fact that they represented 25% of digenean individuals found. In loons, five (28%) of digenean species and striking 38% of individuals found used the non-sympatric intermediate host species. Component communities of grebes were similar to each other (Sørensen similarity index 0.47–0.65) but differed strongly from those hosted by loons (0.00–0.20). We present the first systematically collected evidence of intra-annual changes of helminth component communities in grebes, and provide 20 new host records.

Urbanization breaks up host-parasite interactions: a case study on parasite community ecology of rufous-bellied thrushes (Turdus rufiventris) along a rural-urban gradient.

Urbanization drastically alters natural ecosystems and the structure of their plant and animal communities. Whereas some species cope successfully with these environmental changes, others may go extinct. In the case of parasite communities, the expansion of urban areas has a critical effect by changing the availability of suitable substrates for the eggs or free-larval stages of those species with direct life cycles or for the range of hosts of those species with complex cycles. In this study we investigated the influence of the degree of urbanization and environmental heterogeneity on helminth richness, abundance and community structure of rufous-bellied thrushes (Turdus rufiventris) along a rural-urban gradient in the metropolitan region of Porto Alegre, State of Rio Grande do Sul, Brazil. This common native bird species of southern Brazil hosts 15 endoparasite species at the study region. A total of 144 thrushes were collected with mist nets at 11 sites. The degree of urbanization and environmental heterogeneity were estimated by quantifying five landscape elements: buildings, woodlands, fields, bare lands, and water. Landscape analyses were performed at two spatial scales (10 and 100 ha) taking into account home range size and the potential dispersal distance of thrushes and their prey (intermediate hosts). Mean parasite richness showed an inverse relationship with the degree of urbanization, but a positive relationship with environmental heterogeneity. Changes in the structure of component communities along the rural-urban gradient resulted from responses to the availability of particular landscape elements that are compatible with the parasites' life cycles. We found that the replacement of natural environments with buildings breaks up host-parasite interactions, whereas a higher environmental (substrate) diversity allows the survival of a wider range of intermediate hosts and vectors and their associated parasites.

Extrinsic- and intrinsic-dependent variation in component communities and patterns of aggregations in helminth parasites of great cormorant (Phalacrocorax carbo) from N.E. Poland

In the present study, we investigate the effect extrinsic (habitat and season) and intrinsic (host’s age and sex) factors on the richness, diversity, and structure of parasite component communities and aggregation patterns in the helminth fauna of the great cormorant Phalacrocorax carbo from northeastern Poland. The helminth fauna of cormorants from the brackish water habitat was far richer (30 species) than in those from freshwater lakes (18 species) and strongly depend on season and age of the host. The values of diversity index strongly varied in relation to habitat and host age with clear seasonal differences in the value of diversity index, i.e., its value increased over time in adults from the brackish water habitat and decreased in those from the freshwater lakes. The number of helminths in adult and immature birds varied, depending on the season and habitat: in the brackish water habitat, the overall percentage of helminths was higher in spring than in summer, while in the freshwater habitat a higher proportion of helminths was recorded in summer. During spring, in the brackish water habitat, we observed a higher level of aggregation (for all groups of helminths) than in autumn. The opposite pattern was found in the freshwater habitat. However, this regularity was typical of adult birds only. In immature hosts, the level of aggregation was not predictable and varied among the higher taxa. Our study clearly showed that processes determinate diversity, structure, richness, and patterns of aggregation in helminth assemblages of avian hosts are multi-origin and highly complex.Electronic supplementary materialThe online version of this article (doi:10.1007/s00436-013-3714-7) contains supplementary material, which is available to authorized users.

Temporal and spatial changes in the composition and structure of helminth component communities in European eels Anguilla anguilla in an Adriatic coastal lagoon and some freshwaters in Italy

The composition and diversity of the helminth component communities in eels Anguilla anguilla were determined in three separate localities in Italy: an Adriatic coastal lagoon, Comacchio and two freshwater localities, the River Po and the Lake Piediluco. Data from Comacchio lagoon were analysed over 15 years to determine whether community composition and diversity changed significantly overtime. The community was species rich (nine species, all marine except Proteocephalus macrocephalus) and was dominated by a suite of digeneans: Deropristis inflata, Helicometra fasciata, Lecithochirium musculus and Bucephalus anguillae. The community showed little change in composition over the period, but the relative abundance and dominance of the species did alter. By contrast, the component communities in the freshwater localities were species poor and the dominant species were freshwater acanthocephalans, Pomphorhyncus laevis in River Po and Acanthocephalus rhinensis in Lake Piediluco. The helminth community of Lake Piediluco with five species was richer than that of the River Po with only three species, but was poorer than that of Comacchio lagoons. Similarity indices between samples from Comacchio were high; between the lagoon and the freshwater localities and between the two freshwater localities, similarity indices were very low. Helminth component community structure in coastal lagoons was comparable across Europe. The helminth community in the River Po was similar to those in the River Tiber and other European rivers whilst that in Lake Piediluco was similar to that in other European lakes. Levels of the pathogenic Anguillicoloides crassus in swim bladders were consistently lower in prevalence and abundance in the coastal lagoons than in freshwater localities. This suggests that this parasite may have little impact on migrating eels if they are indeed primarily of marine origin and so it may be of little importance in the recent decline of eel populations throughout Europe.

Survey of flea infestation in cats in Spain

Fleas are a common cause of feline skin disorders as well as vectors of zoonotic diseases. This study evaluated the flea species infesting domestic cats in Spain and assessed factors influencing their distribution. Fleas from 217 cats from 57 localities in Spain were identified and associations between abundance, and host-dependent, host habitat and environmental factors were examined. Variations in infracommunity and component community structure were also explored. Three species were present, of which Ctenocephalides felis (Bouché) (Siphonaptera: Pulicidae) was the most abundant (98.4%), followed by Ctenocephalides canis (Curtis) (1.1%) and Pulex irritans (L.) (Siphonaptera: Pulicidae) (0.5%). Overall abundance and abundances of both C. felis and C. canis were higher on farms than in apartments, but overall flea abundance and abundances of both C. felis and C. canis were lower in rural than urban environments. Overall abundance and C. felis abundance were lower during the warmest months, and mean annual rainfall was positively correlated with overall, C. felis and C. canis abundances. No relationship between the number of species per cat and any host, habitat or physiographical variable was found. Species richness was not correlated with mean annual temperature or rainfall. Flea abundance was mainly associated with host habitat and environmental factors.

Helminth communities from two urban rat populations in Kuala Lumpur, Malaysia.

BackgroundThe prevalence of parasitic infections among commensal animals such as black and brown rats in many tropical countries is high and in comparison with studies on rodents in temperate climates, little is known about the community structure of their parasites. Rodent borne parasites pose threats to human health since people living in close proximity to rodent populations can be exposed to infection.MethodsThe helminth community structures of two urban rat populations in Kuala Lumpur, Malaysia were investigated. The rats were from two contrasting sites in the city caught over a period of 21 months in 2000-2002.ResultsEleven species of helminth parasites comprising seven nematodes (Heterakis spumosum, Mastophorus muris, Nippostrongylus brasiliensis, Syphacia muris, Pterygodermatites tani/whartoni, Gongylonema neoplasticum, Angiostrongylus malaysiensis), three cestodes (Hymenolepis (Rodentolepis) nana, H. diminuta and Taenia taeniaeformis) and one acanthocephalan (Moniliformis moniliformis) were recovered from 346 Rattus rattus and 104 R. norvegicus from two urban sites, Bangsar and Chow Kit, during 2000-2002. Rattus rattus harboured over 60% of all helminths compared with R. norvegicus, although both host species played a dominant role in the different sites with, for example R. norvegicus at Bangsar and R. rattus at Chow Kit accounting for most of the nematodes. Overall 80% of rats carried at least one species of helminth, with the highest prevalences being shown by H. diminuta (35%), H. spumosum (29.8%) and H. nana (28.4%). Nevertheless, there were marked differences in prevalence rates between sites and hosts. The influence of extrinsic (year, season and site) and intrinsic (species, sex and age) factors affecting infracommunity structure (abundance and prevalence of infection) and measures of component community structure were analyzed.ConclusionsSince at least two species of rat borne helminths in Kuala Lumpur have the potential to infect humans, and these showed high prevalences in the rats, the assessment and regular monitoring of infections carried by wild rodents have important roles to play in public health.

Parasite Assemblages of Australian Species of Pseudomys (Rodentia: Muridae: Murinae)

The parasite fauna of many Australian rodents is poorly known. The ectoparasite and helminth faunas of Pseudomys delicatulus, Pseudomys desertor, Pseudomys gracilicaudatus, and Pseudomys hermannsburgensis were determined and compared. In total, 12 species of arthropods, 2 cestodes, and 13 nematodes were found. Species richness of parasites was highest in P. hermannsburgensis and lowest in P. desertor. Despite the sampling effort, the number of parasite species discovered did not reach an asymptote for any of the host species, indicating that the full parasite fauna was not examined. Helminth species richness was highest in the insectivorous P. hermannsburgensis and lower in the obligate herbivores. The structure of parasite component communities was influenced by the social structure of the host species, not surprisingly, with the most highly social species having the highest richness of parasites. Habitat preferences also provided contrast between the helminth component communities, with heligmonellid nematodes occurring in damp woodlands and dominating the parasite fauna of P. gracilicaudatus. Oxyurid nematodes dominated the component communities of the 3 other species, all of which inhabit drier habitats.

Parasites in a man-made landscape: contrasting patterns of trematode flow in a fishpond area in Central Europe

We have explored a large body of novel data focusing on small-scale temporal and spatial patterns in the composition and structure of larval trematode communities in Lymnaea stagnalis (L.) from a typical Central European agricultural landscape. The 5 eutrophic fishponds studied provide excellent environments for the development of species-rich and abundant trematode communities. Nine prevalent species were consistently present in component communities, but had differential contribution to the parasite flow in the 5 ponds resulting in significant contrasting patterns of community similarity and the prevalence of the 3 major transmission guilds driving this similarity. Component communities split into 2 groups: (i) those from the large pond dominated by anatid and larid generalists with active miracidial transmission; and (ii) those from the smaller ponds dominated by 2 plagiorchioideans infecting snails via egg ingestion. We put forward 3 hypotheses for the remarkable differences in larval trematode flow in the similar and closely located eutrophic ponds: (i) species-specific differences in parasite colonization potential displayed by an 'active-passive' dichotomy in miracidial transmission strategies of the species; (ii) top-down effects of pond context on transmission pathways of the trematodes; and (iii) competition as an important mechanism in eutrophic environments with a bottom-up effect on component community structure.