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We surveyed 12 populations of the montane water vole (Arvicola scherman), previously known as the fossorial form of the water vole A. terrestris, in eastern France for antibodies (immunoglobulin G) to Puumala virus (PUUV), lymphocytic choriomeningitis virus (LCMV), and cowpox virus (CPXV). Antibodies to PUUV were found in 9 (5.5) of 164 voles from 7 populations, antibodies to LCMV were found in 13 (26.0) of 50 voles from 2 populations, and antibodies to CPXV were found in 66 (41.8) of 158 voles from 7 populations. Antibody status to CPXV was statistically associated with the phase of the A. schermanpopulation density cycle and the percentage of grassland areas surrounding the sampling sites. [ABSTRACT FROM AUTHOR]

Proper fisheries management of the Atlantic croaker Micropogonias undulatus is necessary in the United States due to the commercial and recreational importance of this fish species. Croaker stock structure in the western North Atlantic has been investigated in the past by various authors, with inconclusive results. In this study, macroparasites were used as biological tags to identify putative croaker stocks in the area between New Jersey and Florida, which encompasses the Mid Atlantic Bight and the South Atlantic Bight separated at Cape Hatteras, North Carolina. The macroparasite community of the fish was identified, showing the presence of 30 species in four phyla, of which several were new host records, and one species, a monogenean, was new to science. A canonical correspondence analysis was applied to determine the variables responsible for parasite species composition, to resolve the question of croaker stock structure in the western North Atlantic Ocean. This analysis showed that latitude was the deciding variable delineating the parasite community composition of the Atlantic croaker. Among the 30 parasites, 15 were identified as putative tags according to qualitative criteria, and then 10 out of those 15 were selected as being appropriate tags using quantitative criteria. These parasite tags support the presence of two stocks roughly separated at the known biogeographical barrier at Cape Hatteras. [ABSTRACT FROM AUTHOR]

Abstract??A central point not yet elucidated in immuno-ecological studies is whether the different ways to assess the immune status of individuals are good indicators of parasite resistance of the host. We investigate the relationship between immunocompetence and the resistance/susceptibility phenotype of five strains of two European subspecies of the house mouse and their hybrids derived from natural populations. The assessment of immunocompetence was measured indirectly by the mass of the spleen and directly by the phytohaemagglutinin (PHA) test. The resistance of each mouse strain to common helminths was previously determined by the distribution of parasite burdens obtained after experimental infection. We found no relationship between the resistance/susceptibility phenotype of strains and the level of PHA response or the size of the spleen. A significant negative correlation was found between residuals of log spleen mass (controlled for body mass) and PHA response, suggesting that these two components of immune function are not independent measures of defence against parasitism. We discuss the validity of these two techniques of measuring immunocompetence and emphasize the importance of taking into account the complexity of the immune system at structural and functional levels in understanding the component of selection attributable to parasitism in the evolution of immunocompetence. [ABSTRACT FROM AUTHOR]

The number of species coexisting in a community may be regulated by local factors (e.g., competitive interactions), or by regional processes (e.g., dispersal from a regional species pool). The relative importance of local and regional processes can be inferred from the shape of the relationship between local and regional species richness. We investigated this relationship in communities of fleas parasitic on small mammals at two spatial scales: between the richness of fleas on individual hosts (infracommunities) and that of fleas on host populations (component communities), and between the richness of component communities and that of the entire regional species pool. We tested linearity (proportional sampling) versus curvilinearity with an asymptote (species saturation) by plotting “local” against “regional” species richness of fleas either among host species or within host species among populations. At the two spatial scales, we found consistent curvilinear relationships between species richness of the more “local” communities and richness of the more “regional” communities. This was true across all host species in the data set and for geographic subsets, even after controlling for the influence of sampling effort on estimates of species richness, and that of host phylogeny in interspecific analyses. We also tested for density compensation in species-poor communities. There was no strong evidence for density compensation at the infracommunity level, although its existence at the component community level appeared likely. Our results suggest that identical patterns in local-versus-regional species richness observed on two different spatial scales arise via different mechanisms: infracommunities appear saturated with flea species most likely because of local processes, such as host immune defenses, whereas component communities are saturated with species through interspecific competition, possibly among larval stages. [ABSTRACT FROM AUTHOR]

Haliotrema species are described and/or reported from the gills of butterfly fishes (Chaetodontidae) from coral reefs of the Indo-West Pacific islands: Moorea (French Polynesia), Palau (Micronesia), Wallis (Wallis and Futuna), New Caledonia, Lizard Island and Heron Island (Great Barrier Reef, Australia). Haliotrema angelopterum sp. nov., a new species of Monogenoidea parasite from seven species of Chaetodon Linnaeus, 1758 (Chaetodontidae), is described. A new redescription and statute are given for Haliotrema aurigae (Yamaguti, 1968) comb. nov., a parasite from ten species of Chaetodon and one species of Heniochus Cuvier, 1816 (Chaetodontidae). New records of Haliotrema scyphovagina Yamaguti, 1968 are reported from two localities and from several host species belonging to the genera Chaetodon and Forcipiger Jordan and McGregor, 1898 (Chaetodontidae). [ABSTRACT FROM AUTHOR]

Morphometrical parameters of the attachment apparatus and copulatory organs of 52 Dactylogyrus species parasitizing 17 species of cyprinid fishes were analysed to test for the existence of reproductive barriers among congeneric species. The minimal spanning tree (MST) method was applied in the analyses. The position of ?real? parasite communities, based on (1) observed infracommunities, (2) a checklist of parasites for a given host in the morphological space, was compared to the position of randomly generated communities using all Dactylogyrus species. The distribution of species similarity within infracommunities (using both attachment and copulatory measurements) was not significantly different from that obtained by simulation, and this trend was similar for both the checklist and observed infracommunities. When real infracommunities were separated according to host specificity (specialists versus generalists), we found differences reflecting similarities in the shapes of attachment and copulatory organs. Within specialists, more similarities in the shape of the attachment apparatus can be found than within generalists, whereas the similarity in copulatory organ shape seems to be random. When generalists are considered, parasite infracommunities with the greater differences in attachment apparatus are also more different in terms of the shape of their copulatory apparatus. We conclude that specialist parasites possess more similarity in attachment apparatus due to specialisation to their host, whereas the species similarity in copulatory organs within infracommunities exhibits a random pattern, but with the copulatory organs being more variable than the attachment apparatus (which may be due to reproductive isolation). The morphology of the copulatory apparatus seems not to be the single factor explaining reproductive isolation among species. [ABSTRACT FROM AUTHOR]

Morphometrical parameters of the attachment apparatus and copulatory organs of 52 Dactylogyrus species parasitizing 17 species of cyprinid fishes were analysed to test for the existence of reproductive barriers among congeneric species. The minimal spanning tree (MST) method was applied in the analyses. The position of ?real? parasite communities, based on (1) observed infracommunities, (2) a checklist of parasites for a given host in the morphological space, was compared to the position of randomly generated communities using all Dactylogyrus species. The distribution of species similarity within infracommunities (using both attachment and copulatory measurements) was not significantly different from that obtained by simulation, and this trend was similar for both the checklist and observed infracommunities. When real infracommunities were separated according to host specificity (specialists versus generalists), we found differences reflecting similarities in the shapes of attachment and copulatory organs. Within specialists, more similarities in the shape of the attachment apparatus can be found than within generalists, whereas the similarity in copulatory organ shape seems to be random. When generalists are considered, parasite infracommunities with the greater differences in attachment apparatus are also more different in terms of the shape of their copulatory apparatus. We conclude that specialist parasites possess more similarity in attachment apparatus due to specialisation to their host, whereas the species similarity in copulatory organs within infracommunities exhibits a random pattern, but with the copulatory organs being more variable than the attachment apparatus (which may be due to reproductive isolation). The morphology of the copulatory apparatus seems not to be the single factor explaining reproductive isolation among species. [ABSTRACT FROM AUTHOR]

Maturation time is a pivotal life-history trait of parasitic nematodes, determining adult body size, as well as daily and total fecundity. Recent theoretical work has emphasized the influence of prematurational mortality on the optimal values of age and size at maturity in nematodes. Eosinophils are a family of white blood cells often associated with infections by parasitic nematodes. Although the role of eosinophils in nematode resistance is controversial, recent work has suggested that the action of these immune effectors might be limited to the larval stages of the parasite. If eosinophils act on larval survival, one might predict, in line with theoretical models, that nematode species living in hosts with large eosinophil numbers should show reduced age and size at maturity. We tested this prediction using the association between the pinworms (Oxyuridae, Nematoda) and their primate hosts. Pinworms are highly host specific and are expected to be involved in a coevolutionary process with their hosts. We found that the body size of female parasites was negatively correlated with eosinophil concentration, whereas the concentration of two other leucocyte families--neutrophils and lymphocytes--was unrelated to female body size. Egg size of parasites also decreased with host eosinophil concentration, independently of female size. Male body size was unrelated to host immune parameters. Primates with the highest immune defence, therefore, harbour small female pinworms laying small eggs. These results are in agreement with theoretical expectations and suggest that life histories of oxyurid parasites covary with the immune defence of their hosts. Our findings illustrate the potential for host immune defence as a factor driving parasite life-history evolution. [ABSTRACT FROM AUTHOR]

Abstract We investigated the pattern of helminth species diversity in woodmouse, Apodemus sylvaticus, on western Mediterranean islands. We first performed a survey of the helminth fauna of A. sylvaticus in Sicily. Despite the small sampling effort, parasite species richness in Sicily is large in comparison with parasite species richness on other Mediterranean islands. We tested the nestedness of helminth parasite species from a number of Mediterranean localities using data compiled from epidemiological surveys of the helminth species of A. sylvaticus. We showed a nested pattern for woodmouse helminth species on western Mediterranean islands which suggests that the distribution of parasites on these islands is not the result of a random process. Properties of helminth parasites such as taxonomic group or life cycle and properties of the host population localities such as area size or the stability of the environment (estimated by mammal species diversity) contribute to the nestedness. [ABSTRACT FROM AUTHOR]