Search

Ixodes apronophorus Schulze, 1924, the marsh tick, belongs to a group of so-called "neglected" ixodid ticks, which remain underexplored compared to the most well-studied species of the genus Ixodes (I. ricinus, I. persulcatus). In this communication, we analyze and summarize the quantitative data on the abundance of this parasite, its geographical distribution, and the diversity of its small mammal hosts in the region of West Siberia (Asiatic Russia). The analyzed data represent a continuous series of observations made between 1953 and 2007, which constitutes one of the longest timeseries ever studied by acarologists. It is shown that the marsh tick in West Siberia is most common in the northern forest steppe and southern taiga landscape zones, being distributed south of 60° N. Among 24 species of small mammals registered as hosts for I. apronophorus in the studied region, three play the most important role: the European water vole (Arvicola amphibius), the tundra vole (Microtus oeconomus), and the Northern red-backed vole (Clethrionomys rutilus). The data characterizing parasitism of the marsh tick on these three hosts in various landscape zones and subzones are provided. We can report a weak albeit significant negative relationship between the abundances of I. apronophorus and its small mammal hosts. The possible explanation lies in the mismatch between the cycles of abundance characteristic of the tick and its hosts. [ABSTRACT FROM AUTHOR]

Dark diversity (DD) is represented by species that may potentially inhabit a locality but are absent. We applied this approach to identify missing species and links in the interaction networks of fleas and gamasid mites with small mammals and asked (a) which factors affect host, parasite or interaction (= link) DD and (b) whether the probability of an interaction to be missing is associated with the host and/or the parasite traits.The DD of both parasite taxa increased with an increase in host DD. The DD of interactions increased with an increase in the DD of the respective parasite taxon. The quantity of missing flea–host links was affected by environment, whereas that of mite–host links was affected by host DD.The values of the probability of an interaction to belong to DD were similar (= repeatable) within host and flea, but not mite, species. The probability of a flea–host and a mite–host interaction to be missing was higher if social hosts that possessed complex shelter, had low population densities but large geographic ranges.The probability of a flea–host interaction to be missing was higher if a flea species was not abundant and preferred to spend most of its life on either the body or nest of its host but not both.In conclusion, we propose a relatively simple way to apply the dark diversity concept to assess the quantity of missing links in parasite–host networks, to identify these links, and to relate the probability of a link to be missing with parasite and/or host traits. [ABSTRACT FROM AUTHOR]

1. We applied a Markov random fields/conditional random fields (MRF/CRF) modelling to understand whether and how species associations in ectoparasite infracommunities of small mammals vary along environmental gradients across space and time. 2. We analysed the variation in species associations in flea and mite infracommunities of seven host species across localities (spatial scale) and time periods (in the same locality; temporal scale). 3. The performance of the CRF models differed between ectoparasite taxa, scales, and host species. The model performance for flea and mite infracommunities in the majority of host species was satisfying although the proportions of correctly predicted positive occurrences and model sensitivity were moderate. 4. The probability of occurrence of many flea and mite species depended mostly on the occurrence of another flea and mite species (respectively), with many negative interspecific interactions, although occurrences of some species were mainly affected by environmental factors. The patterns of pairwise associations between some ectoparasite species were affected by environmental factors. 5. Although many ectoparasite pairs demonstrated stability in the strength or sign of association across space or time, interactions between other species pairs were spatially or temporally variable, with the association between the same pair of species being stable in one host species and variable in another host species. 6. We conclude that ectoparasite associations are mediated by the off‐host environment and may depend on the life histories of both host and ectoparasite species. [ABSTRACT FROM AUTHOR]

We studied patterns of compositional, functional, and phylogenetic α- and β-diversity in flea and gamasid mite infracommunities of small Siberian mammals, taking into account host-associated (species) and environmental (biome or sampling period) factors. We asked: (a) How do these factors and their interactions affect infracommunity diversity? (b) Does infracommunity composition, in terms of species, traits, and phylogenetic lineages, deviate from random? (c) Are species, traits, and phylogenetic lineages in infracommunities clustered or overdispersed?, and (d) Do patterns of diversity differ between the three diversity facets and/or the two ectoparasite taxa? We found that the α-diversity of infracommunities was strongly affected by host species, biome, and sampling period. The highest proportion of infracommunity diversity in both taxa was associated with the interaction between either host species and biome or host species and sampling period. Infracommunities of both taxa within, as well as between, host species, biomes, and sampling periods were characterized by the clustering of species, traits and lineages. The patterns of the effects of host species, biome, and sampling period on infracommunity diversity were congruent among the three diversity facets in both fleas and mites. We conclude that the assembly patterns in ectoparasite infracommunities mirror those characteristics of component and compound communities. [ABSTRACT FROM AUTHOR]

Aim: We studied compositional turnover in two ectoparasite taxa asking whether (a) the main driver of turnover (environmental factors, host composition, or distance) is the same in both taxa; (b) the turnover of rare and widespread fleas and mites is driven by different factors; and (c) the turnover of either fleas or mites or both respond to the same environmental gradients as the turnover of their hosts. Location: Northern and central Palaearctic. Time period: 1959–2004. Main taxa studied: Fleas, gamasid mites, mammals. Methods: We used data on fleas and mites collected from 30 and 20 regions, respectively, and applied a novel metric, zeta diversity, and a novel approach, multi‐site generalized dissimilarity modelling (MS‐GDM). Results: In fleas, variance explained by the models with host turnover as a predictor was higher than that of models with environment and distance or environment only. In mites, similar proportions of variance were explained by models with and without a host‐associated predictor. Host turnover strongly affected the compositional turnover of fleas, whereas mite turnover was equally influenced by host turnover and dissimilarity in air temperature. When host turnover was removed from the models, temperature became the most important predictor of turnover, followed by precipitation (for both taxa) and distance (for fleas). The effects of host turnover and environment were stronger for turnover of rare than widespread species. Temperature was the most important predictor of the host turnover independently of whether distance was included in the model. Main conclusions: We conclude that the strength and manifestation of the effects of host compositional turnover as compared to environmental dissimilarity differ between ectoparasite taxa. Moreover, the application of MS‐GDM allowed us to reveal patterns that were obscured or distorted in earlier studies. [ABSTRACT FROM AUTHOR]

1. This study tested the relationships between the probability of pairwise species co‐occurrence and pairwise dissimilarity in their traits in infracommunities (across assemblages harboured by conspecific individual hosts within a locality), component communities (across assemblages harboured by host species within a locality), and compound communities (across assemblages in different localities) of fleas and gamasid mites parasitic on small mammals in Western Siberia. 2. A significant, albeit weak, tendency was found for flea communities harboured by conspecific host individuals, host species, and host communities to be composed of similar species. No relationship between the probability of co‐occurrence and trait dissimilarity was detected for mite communities at any hierarchical scale. 3. For fleas, this study explained the link between positive co‐occurrence and trait dissimilarity by a process resembling environmental filtering realised mainly via host traits for infracommunities and component communities and via off‐host environment for compound communities, thus suggesting that the identical shape of the relationships between co‐occurrence and trait dissimilarity at different scales was driven by different mechanisms. 4. The explanation of the lack of this relationship in mites included: (i) the paucity of the subset of mite traits used in this study and its potential inadequacy for the question at hand; and (ii) possible masking of the effect induced by one trait on co‐occurrence owing to the lack of this effect induced by another trait(s). 5. Caution is recommended regarding the compilation of a dataset involving multiple traits, its analysis, and the interpretation of the results. [ABSTRACT FROM AUTHOR]

We 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. [ABSTRACT FROM AUTHOR]

The functional diversity structure of a community can be represented as a combination of three additive components (species dominance D, functional redundancy R, and functional diversity Q) (DRQ approach in which different facets of functional differences between species are considered simultaneously). We applied this concept to assemblages of fleas and gamasid mites parasitic on small mammals at continental (across regions of the Palearctic) and regional (across sampling sites in Slovakia) scales and asked: What are the relative effects of host species, biome/habitat type, and geographic locality on the DRQ composition of a parasite assemblage? At the continental scale, regions were partitioned according to predominant biome or geographic position in a continental section. At the regional scale, sampling sites were partitioned according to habitat type or geographic locality. We tested for differences in the functional diversity structure (measured as the DRQ composition) of an ectoparasite assemblage (a) within a host species between biomes/habitat types or continental sections/localities and (b) between host species within a biome/habitat type or a continental section/locality. At both scales, the functional diversity structure of both flea and mite assemblages differed mainly between host species within a biome/habitat or geographic regions/locations, whereas differences in the DRQ composition between biomes/habitats or geographic regions/locations were only detected in a few host species. We compare our results with the results of earlier studies and conclude that the DRQ approach has an advantage over a single diversity metric and allows a better understanding of spatial variation in different facets of ectoparasite diversity.

This article represents the third (and last) part of the catalogue of ectoparasitic gamasid mites associated with small mammals in Asiatic Russia (Siberia and the Russian Far East). A total of 19 species of the genus Hirstionyssus Fonseca, 1948 are indexed, with data on their taxonomic position, nomenclature, host range, and distribution within the region. As a conclusion, a brief overview of fauna of ectoparasitic gamasid mites parasitising Micromammalia (except bats) of Asiatic Russia is given. In total, 71 mite species belonging to nine genera of three families (Haemogamasidae, Hirstionyssidae, Laelapidae) are recorded and divided among taxonomic and ecological groupings.

We provide a list of the species of the family Haemogamasidae Oudemans, 1926 living in Asiatic Russia, with data on their synonymy, distribution, and relationships with mammal hosts. In total, 23 species of mites distributed between two genera (Eulaelaps Berlese, 1903, and Haemogamasus Berlese, 1889) are covered.

Twenty-nine species of mites of the family Laelapidae s. str. have been recorded as associated with small mammals (rodents, insectivores) in Asiatic Russia (Siberia and the Russian Far East). These species belong to two subfamilies (Laelapinae, Myonyssinae) and six genera: Androlaelaps Berlese, 1903, Dipolaelaps Zemskaya & Piontkovskaya, 1960, Laelaps C.L. Koch, 1836, Hyperlaelaps Zakhvatkin, 1948, Myonyssus Tiraboschi, 1904, Oryctolaelaps Lange, 1955. A list of the species, with data on synonymy, geographic ranges, and relationships with mammal hosts is provided. Some considerations concerning patterns of distribution of the parasitic Laelaptidae of Asiatic Russia are presented as well as their classifications from the point of view of known host association records.