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Bruno Baur - One of the best experts on this subject based on the ideXlab platform.
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Parasitic Mites influence intra‐ and interpopulational variation in sperm length in a simultaneous hermaphrodite land snail (Gastropoda: Helicidae)
Biological Journal of the Linnean Society, 2014Co-Authors: Ellen M. Haeussler, Dénes Schmera, Bruno BaurAbstract:Sperm morphology can be highly variable among species, but less is known about patterns of population differentiation within species. Sperm morphology is under strong sexual selection, may evolve rapidly, and often co-varies with other reproductive traits that differ between populations. We investigated variation in sperm morphology in the simultaneous hermaphrodite land snail Arianta arbustorum in relation to Parasitic mite infection. Variation in total sperm length and sperm head length was assessed in 23 populations sampled across the distributional range of the species in Central and Northern Europe. We found a pronounced variation in total sperm length among the populations studied, with a difference of 11.0% of total sperm length between the shortest and longest population means. Differences among populations explained 62.9% of the variance in total sperm length, differences among individual snails within population 23.4% and differences within individual snail 13.7%. Mantel tests showed that interpopulation differences in total sperm length increased significantly with geographical distance between populations. A minimal adequate model revealed that Parasitic infection had a positive effect and longitude a negative effect on total sperm length. Thus, independent of the population examined, mite-infected individuals of A. arbustorum produced larger sperm than uninfected snails and total sperm length decreased from west to east. Sperm head length also varied among populations, but it was not influenced by any of the factors examined. In a subsample of 12 populations restricted to the mountains of Switzerland (elevational range 440–2485 m a.s.l.), total sperm length decreased with increasing elevation. Our results suggest that selection pressures acting among populations may differ from those acting within. Stabilizing selection might be a possible mechanism for producing the reduced variation observed in sperm length within a population. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113, 1036–1046.
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contact based transmission models in terrestrial gastropod populations infected with Parasitic Mites
International Journal for Parasitology, 2010Co-Authors: Hans U Schupbach, Bruno BaurAbstract:Parasite transmission fundamentally affects the epidemiology of host–parasite systems, and is considered to be a key element in the epidemiological modelling of infectious diseases. Recent research has stressed the importance of detailed disease-specific variables involved in the transmission process. Riccardoella limacum is a hematophagous mite living in the mantle cavity of terrestrial gastropods. In this study, we experimentally examined whether the transmission success of R. limacum is affected by the contact frequency, parasite load and/or behaviour of the land snail Arianta arbustorum, a common host of R. limacum. In the experiment the transmission success was mainly affected by physical contacts among snails and slightly influenced by parasite intensity of the infected snail. Using these results we developed two different transmission models based on contact frequencies and transmission probability among host snails. As parameters for the models we used life-history data from three natural A. arbustorum populations with different population densities. Data on contact frequencies of video-recorded snail groups were used to fit the density response of the contact function, assuming either a linear relationship (model 1) or a second-degree polynomial relationship based on the ideal gas model of animal encounter (model 2). We calculated transmission coefficients (β), basic reproductive ratios (R0) and host threshold population densities for parasite persistence in the three A. arbustorum populations. We found higher transmission coefficients (β) and larger R0-values in model 1 than in model 2. Furthermore, the host population with the highest density showed larger R0-values (16.47–22.59) compared to populations with intermediate (2.71–7.45) or low population density (0.75–4.10). Host threshold population density for parasite persistence ranged from 0.35 to 2.72 snails per m2. Our results show that the integration of the disease-relevant biology of the organisms concerned may improve models of host–parasite dynamics.
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Parasitic Mites influence fitness components of their host the land snail arianta arbustorum
Invertebrate Biology, 2008Co-Authors: Hans U Schupbach, Bruno BaurAbstract:Parasites can influence the population dynamics of their hosts by affecting life-history strategies and behavior. The hematophageous mite Riccardoella limacum lives In the lung cavity of terrestrial gastropods. We used correlational and experimental approaches to investigate the influence of parasite infection on the behavior and life-history traits of the simultaneously hermaphroditic land snail Arianta arbustorum, a common host of R. limacum. Naturally infected individuals of A. arbustorum, collected in the wild, showed a decreased activity compared with uninfected snails. The reproductive output, expressed as the number of eggs deposited in a reproductive season, was reduced in mite-infected hosts. However, the hatching success of the eggs laid by parasitized snails was slightly higher than that of uninfected individuals. We also examined winter survival in 361 adults of A. arbustorum collected from four natural populations. The prevalence of mite infection ranged from 44.8 Populations (snails in the fourth population were not infected). Winter Survival was reduced in infected snails in two out of three populations. Furthermore, experimentally infected snails from an uninfected population showed a reduced winter survival compared with control snails. Our results indicate that parasite pressure imposed by members of R. limacum may influence life history in A. arbustorum.
Masahiro Yoneda - One of the best experts on this subject based on the ideXlab platform.
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Worldwide migration of Parasitic Mites as a result of bumblebee commercialization
Population Ecology, 2006Co-Authors: Koichi Goka, Kimiko Okabe, Masahiro YonedaAbstract:We investigated the status of infestation by a tracheal mite, Locustacarus buchneri, in natural populations of a Japanese native bumblebee species, Bombus hypocrita, collected on Hokkaido Island and in the Aomori prefecture between 1997 and 2001. We also investigated mite infestation in commercial colonies of the European bumblebee, Bombus terrestris, imported from the Netherlands and Belgium, and the Japanese native species, B. ignitus, imported from the Netherlands, between 1997 and 2001. We detected Mites in natural populations of the two B. hypocrita subspecies and in the commercial colonies. Analysis of variations in 535 bp sequences of the mitochondrial cytochrome oxidase subunit 1 (CO1) gene showed that the mite haplotypes in the native populations and in the imported colonies did not overlap in 1997–1999, but in 2000–2001 some Mites possessing European CO1 haplotypes were detected in the natural populations of Japanese native bumblebees. In addition, many Mites possessing Japanese haplotypes were detected in the imported commercial colonies from Europe. Considering the fact that the Japanese native bumblebees, B. hypocrita, were once exported to Europe for commercialization, these results suggest that bumblebee commercialization has caused overseas migration and cross-infestation of Parasitic Mites among natural and commercial colonies. However, because the Japanese and European CO1 haplotypes were closely related, there was a possibility that the European haplotypes found in the Mites in the Hokkaido Island revealed native variation. To clarify the status of mite invasion, further detailed analysis of genetic variation of the mite, using other genetic markers on additional samples, need to be performed.
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Bumblebee commercialization will cause worldwide migration of Parasitic Mites
Molecular ecology, 2001Co-Authors: Koichi Goka, Kimiko Okabe, Masahiro Yoneda, Satomi NiwaAbstract:We investigated natural populations of three Japanese native bumblebee species to determine the status of infestation by a tracheal mite, Locustacarus buchneri, which we had earlier detected in introduced commercial colonies of the European bumblebee, Bombus terrestris. We also investigated mite infestation in commercial colonies of a Japanese native species, B. ignitus, which are mass-produced in the Netherlands and reimported into Japan. We detected the mite in both natural and commercial colonies of the Japanese species. Comparison of 555 bp sequences of the mitochondrial DNA (mtDNA) cytochrome oxidase 1 (CO1) gene from the mite showed that there were seven haplotypes, on the basis of combinations of substitutions at eight sites in the gene. The haplotypes of the Mites in the Japanese native bumblebees and the haplotypes of the Mites in B. terrestris did not overlap; however, mtDNA of Mites detected in the commercial colonies of B. ignitus possessed the same sequence as a European haplotype. These results indicate that transportation of bumblebee colonies will cause overseas migration of Parasitic Mites of different origins.
Koichi Goka - One of the best experts on this subject based on the ideXlab platform.
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Worldwide migration of Parasitic Mites as a result of bumblebee commercialization
Population Ecology, 2006Co-Authors: Koichi Goka, Kimiko Okabe, Masahiro YonedaAbstract:We investigated the status of infestation by a tracheal mite, Locustacarus buchneri, in natural populations of a Japanese native bumblebee species, Bombus hypocrita, collected on Hokkaido Island and in the Aomori prefecture between 1997 and 2001. We also investigated mite infestation in commercial colonies of the European bumblebee, Bombus terrestris, imported from the Netherlands and Belgium, and the Japanese native species, B. ignitus, imported from the Netherlands, between 1997 and 2001. We detected Mites in natural populations of the two B. hypocrita subspecies and in the commercial colonies. Analysis of variations in 535 bp sequences of the mitochondrial cytochrome oxidase subunit 1 (CO1) gene showed that the mite haplotypes in the native populations and in the imported colonies did not overlap in 1997–1999, but in 2000–2001 some Mites possessing European CO1 haplotypes were detected in the natural populations of Japanese native bumblebees. In addition, many Mites possessing Japanese haplotypes were detected in the imported commercial colonies from Europe. Considering the fact that the Japanese native bumblebees, B. hypocrita, were once exported to Europe for commercialization, these results suggest that bumblebee commercialization has caused overseas migration and cross-infestation of Parasitic Mites among natural and commercial colonies. However, because the Japanese and European CO1 haplotypes were closely related, there was a possibility that the European haplotypes found in the Mites in the Hokkaido Island revealed native variation. To clarify the status of mite invasion, further detailed analysis of genetic variation of the mite, using other genetic markers on additional samples, need to be performed.
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Bumblebee commercialization will cause worldwide migration of Parasitic Mites
Molecular ecology, 2001Co-Authors: Koichi Goka, Kimiko Okabe, Masahiro Yoneda, Satomi NiwaAbstract:We investigated natural populations of three Japanese native bumblebee species to determine the status of infestation by a tracheal mite, Locustacarus buchneri, which we had earlier detected in introduced commercial colonies of the European bumblebee, Bombus terrestris. We also investigated mite infestation in commercial colonies of a Japanese native species, B. ignitus, which are mass-produced in the Netherlands and reimported into Japan. We detected the mite in both natural and commercial colonies of the Japanese species. Comparison of 555 bp sequences of the mitochondrial DNA (mtDNA) cytochrome oxidase 1 (CO1) gene from the mite showed that there were seven haplotypes, on the basis of combinations of substitutions at eight sites in the gene. The haplotypes of the Mites in the Japanese native bumblebees and the haplotypes of the Mites in B. terrestris did not overlap; however, mtDNA of Mites detected in the commercial colonies of B. ignitus possessed the same sequence as a European haplotype. These results indicate that transportation of bumblebee colonies will cause overseas migration of Parasitic Mites of different origins.
U. Gerson - One of the best experts on this subject based on the ideXlab platform.
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Frequency-dependent host selection by Parasitic Mites: a model and a case study
Oecologia, 1995Co-Authors: S. Izraylevich, O. Hasson, U. GersonAbstract:Previous studies on frequency-dependent food selection (changing food preferences in response to changes in relative food abundance) have focused on predators and parasitoids. These organisms utilize several victims during their lifetime. We introduce the case of parasites which, having accepted a host, do not change it. We propose two alternative models to explain the biased occurrence of parasites on different host types: (1) through the option of rejecting less-preferred hosts prior to accepting one of them; (2) by differential parasite survival on different host types. These models predict that host rejection, but not differential survival, can create frequency-dependent parasitism (FDP). Unlike previously described factors responsible for frequency dependence of food selection, which act through changing the foraging behaviour of individual predators or parasitoids, FDP involves no adjustment of parasite foraging strategy according to previous feeding experience. The mite Hemisarcoptes coccophagus is an obligate parasite of armoured scale insects (Homptera: Diaspididae). Our field data show that H. coccophagus is found more frequently on ovipositing than on young host females. Our model, combining the effects of host rejection and differential survival, is used to estimate the relative contribution of these factors to parasite biased occurrence on different hosts. The contribution of differential survival was dominant in H. coccophagus , and overode any effect of host rejection. Nevertheless, our prediction that FDP may be found in parasites is supported by literature data about a Parasitic water mite.
Andy J. Green - One of the best experts on this subject based on the ideXlab platform.
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Parasitism by water Mites in native and exotic Corixidae: Are Mites limiting the invasion of the water boatman Trichocorixa verticalis (Fieber, 1851)?
Journal of Insect Conservation, 2015Co-Authors: Marta I. Sánchez, Cristina Coccia, Antonio G. Valdecasas, Luz Boyero, Andy J. GreenAbstract:The water boatman Trichocorixa verticalis verticalis (Fieber 1851) is originally from North America and has been introduced into the southern Iberian Peninsula, where it has become the dominant Corixidae species in saline wetlands. The reasons for its success in saline habitats, and low abundance in low salinity habitats, are poorly known. Here we explore the potential role of water Mites, which are typical parasites of hemipterans, in the invasion dynamics of T. v. verticalis . We compared infection levels between T. v. verticalis and the natives Sigara lateralis (Leach, 1817) and S. scripta (Rambur, 1840). No Mites were found in saline wetlands where T. v. verticalis is highly dominant. Larvae of two mite species were identified infecting corixids in habitats of lower salinity: Hydrachna skorikowi and Eylais infundibulifera . Total parasite prevalence and prevalence of E. infundibulifera were significantly higher in T. v. verticalis compared with S. lateralis and S. scripta . Mean abundance of total infection and of E. infundibulifera and H. skorikowi were also higher in T. v. verticalis . When infected with H. skorikowi , native species harbored only one or two parasite individuals, while the smaller T. v. verticalis carried up to seven Mites. When infected with E. infundibulifera , native species harboured only one parasite individual, while T. v. verticalis carried up to 6. Mite size didn’t differ among host species, suggesting that all are suitable for engorgement. Both mite species showed a negative correlation between prevalence and salinity. T. v. verticalis susceptibility to Parasitic Mites may explain its low abundance in low salinity habitats, and may contribute to the conservation of native corixids. The success of T. v. verticalis in saline wetlands may be partly explained by the absence of Parasitic Mites, which are less halotolerant.
