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ABSTRACTThe reality of spatial clinal variation in morphological traits of freshwater pulmonate snails (Gastropoda: Pulmonata) has repeatedly been questioned or totally discounted. There is a lack of sound statistical evidence in the articles hitherto published on this subject supporting these claims. Here, by means of different analytical methods (analysis of spatial autocorrelation, linear regression analysis, canonical correlation analysis and others), we demonstrate that shell variation in the dwarf pond snail, Galba truncatula, is patterned in space throughout the northern and central Palearctic, with latitudinally-oriented clines in body size and in some shell proportions. Shell size in G. truncatula decreases with latitude and temperature, representing a special case of converse Bergmann cline. However, the temperature itself is hardly the main driver of shell size variation. It is argued that the shorter growing seasons at high latitudes may represent a better explanation for the observed trend. Shell proportions in the dwarf pond snails vary weakly at the macrogeographic scale, being spatially patterned at lower (mesogeographic) scales around 1200–1500?km. In general, spatial variation in G. truncatula shell size is decoupled from variation in shell shape, demonstrating clear scale-dependence similar to that found in different species of terrestrial (non-aquatic) pulmonate snails. 相似文献
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Krasnov BR Stanko M Matthee S Laudisoit A Leirs H Khokhlova IS Korallo-Vinarskaya NP Vinarski MV Morand S 《Oecologia》2011,166(4):1099-1110
We studied the co-occurrence of flea species in infracommunities of 16 rodents from four regions (South Africa, Tanzania,
central Europe and western Siberia) using null models, and predicted that flea co-occurrences will be expressed more strongly
in male than in female hosts. We examined patterns of co-occurrence (measured as the C score) in infracommunities of fleas that are parasitic on male and female hosts by comparing co-occurrence frequencies with
those expected by chance. When a significant degree of nonrandomness in flea co-occurrences was detected, it indicated aggregative
infracommunity structure. In Tanzanian rodents, no significant flea co-occurrences were detected in either male or female
hosts. In a South African rodent, significant flea co-occurrences were not detected in males, but were found in females in
some localities. In Palaearctic rodents, significant nonrandomness was detected either equally for males and females or more
frequently in males than in females. Meta-analyses demonstrated that the frequency of the detection of nonrandomness in flea
co-occurrences was significantly higher in male than in female hosts. The values of the standardized effect size (SES) for
the C score differed significantly among host species, but not between host genders. When the Palaearctic hosts were analyzed separately,
the effects of both host gender and species appeared to be significant, with the SES values for the C score in males being smaller than those in females. The strength of the gender difference in the manifestation of flea community
structure increased with increasing gender difference in flea species richness, and with decreasing gender difference in flea
prevalence for the Palaearctic hosts. We conclude that male hosts are the main drivers of flea infracommunity structure. However,
the manifestation of gender bias in flea community structure varies among host species, and is likely determined by the pattern
of species-specific spatial behavior. 相似文献
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mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species 总被引:4,自引:0,他引:4
Reconstructions of the human-African great ape phylogeny by using
mitochondrial DNA (mtDNA) have been subject to considerable debate. One
confounding factor may be the lack of data on intraspecific variation. To
test this hypothesis, we examined the effect of intraspecific mtDNA
diversity on the phylogenetic reconstruction of another Plio- Pleistocene
radiation of higher primates, the fascicularis group of macaque (Macaca)
monkey species. Fifteen endonucleases were used to identify 10 haplotypes
of 40-47 restriction sites in M. mulatta, which were compared with similar
data for the other members of this species group. Interpopulational,
intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of
divergence time and branching order incorporating this variation were
substantially different from those based on single representatives of each
species. We conclude that intraspecific mtDNA diversity is substantial in
at least some primate species. Consequently, without prior information on
the extent of genetic diversity within a particular species, intraspecific
variation must be assessed and accounted for when reconstructing primate
phylogenies. Further, we question the reliability of hominoid mtDNA
phylogenies, based as they are on one or a few representatives of each
species, in an already depauperate superfamily of primates.
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Two Radix spp. (Gastropoda: Lymnaeidae) endemic to thermal springs around Lake Baikal represent ecotypes of the widespread Radix auricularia 下载免费PDF全文
Olga Aksenova Maxim Vinarski Ivan Bolotov Alexander Kondakov Yulia Bespalaya Alyona Tomilova Inga Paltser Mikhail Gofarov 《Journal of Zoological Systematics and Evolutionary Research》2017,55(4):298-309
In this study, we re‐examine two species of freshwater gastropods of the genus Radix Montfort, 1810 (family Lymnaeidae), endemic to the geothermal springs in the Lake Baikal region in the southern part of eastern Siberia — Lymnaea (Radix) hakusyensis Kruglov et Starobogatov, 1989, and Lymnaea (Radix) thermobaicalica Kruglov et Starobogatov, 1989. The alleged species status of these endemics has been re‐assessed by means of an integrative approach combining molecular genetic taxonomy techniques with the traditional methods based on shell and soft body morphology. Phylogenetic reconstructions were made using both mitochondrial (COI) and nuclear (ITS2) DNA markers. We used topotypic samples of both species and specimens sampled from other sites around Lake Baikal. The results demonstrate that the two endemic species are only synonyms of a widespread Holarctic species, Radix auricularia (Linnaeus, 1758), and represent its intraspecific morph (ecotype) adapted to living in thermal springs. A new synonymy is proposed: Thermoradix Kruglov et Starobogatov, 1989 = Radix Montfort, 1810 (syn. n.). 相似文献
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Jane L Wagstaff Jonathan N Pruneda Stefan MV Freund David Komander 《The EMBO journal》2017,36(24):3555-3572
The Ser/Thr protein kinase PINK1 phosphorylates the well‐folded, globular protein ubiquitin (Ub) at a relatively protected site, Ser65. We previously showed that Ser65 phosphorylation results in a conformational change in which Ub adopts a dynamic equilibrium between the known, common Ub conformation and a distinct, second conformation wherein the last β‐strand is retracted to extend the Ser65 loop and shorten the C‐terminal tail. We show using chemical exchange saturation transfer (CEST) nuclear magnetic resonance experiments that a similar, C‐terminally retracted (Ub‐CR) conformation also exists at low population in wild‐type Ub. Point mutations in the moving β5 and neighbouring β‐strands shift the Ub/Ub‐CR equilibrium. This enabled functional studies of the two states, and we show that while the Ub‐CR conformation is defective for conjugation, it demonstrates improved binding to PINK1 through its extended Ser65 loop, and is a superior PINK1 substrate. Together our data suggest that PINK1 utilises a lowly populated yet more suitable Ub‐CR conformation of Ub for efficient phosphorylation. Our findings could be relevant for many kinases that phosphorylate residues in folded protein domains. 相似文献
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Boris R. Krasnov Maxim V. Vinarski Natalia P. Korallo-Vinarskaya David Mouillot Robert Poulin 《Oecologia》2009,160(1):175-185
Within a community, the abundance of any given species depends in large part on a network of direct and indirect, positive
and negative interactions with other species, including shared enemies. In communities where experimental manipulations are
often impossible (e.g., parasite communities), census data can be used to evaluate the strength or frequency of positive and
negative associations among species. In ectoparasite communities, competitive associations can arise because of limited space
or food, but facilitative associations can also exist if one species suppresses host immune defenses. In addition, positive
associations among parasites could arise merely due to shared preferences for the same host, without any interaction going
on. We used census data from 28 regional surveys of gamasid mites parasitic on small mammals throughout the Palaearctic, to
assess how the abundance of individual mite species is influenced by the abundance and diversity of other mite species on
the same host. After controlling for several confounding variables, the abundance of individual mite species was generally
positively correlated with the combined abundances of all other mite species in the community. This trend was confirmed by
meta-analysis of the results obtained for separate mite species. In contrast, there were generally no consistent relationships
between the abundance of individual mite species and either the species richness or taxonomic diversity of the community in
which they occur. These patterns were independent of mite feeding mode. Our results indicate either that synergistic facilitative
interactions among mites increase the host’s susceptibility to further attacks (e.g., via immunosuppression) and lead to different
species all having increased abundance on the same host, or that certain characteristics make some host species preferred
habitats for many parasite species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Maxim V. Vinarski Olga V. Aksenova Yulia V. Bespalaya Alexander V. Kondakov Alena A. Tomilova Irina S. Khrebtova Mikhail Yu. Gofarov Ivan N. Bolotov 《Journal of Zoological Systematics and Evolutionary Research》2021,59(1):44-59
The taxonomic position of three nominal species of lymnaeid snails placed by Kruglov & Starobogatov (1993) into the subgenus Lymnaea (Pacifimyxas) Kruglov & Starobogatov, 1985, has been re‐assessed based on a molecular genetic study of topotypic specimens and an examination of the type series and other materials available. It has been shown that the two species, Lymnaea (Pacifimyxas) magadanensis Kruglov & Starobogatov, 1985 and Lymnaea (Pacifimyxas) streletzkajae Kruglov & Starobogatov, 1985, are identical with the species Kamtschaticana kamtschatica (Middendorff, 1850) and must be treated as its junior synonyms. Hence, Pacifimyxas becomes a junior synonym of Kamtschaticana Kruglov & Starobogatov, 1984. The taxonomic identity of the third species of Pacifimyxas, Lymnaea (Pacifimyxas) perpolita, remains obscure, and this species is considered here as taxon inquirendum. Two other nominal species, Lymnaea aberrans (Westerlund, 1897) and Lymnaea middendorffi (W. Dybowski, 1904), have been synonymized with K. kamtschatica based on morphological and geographical evidence. The lectotype of Limnaea peregra var. middendorffi is designated. The actual level of species richness in the Beringian freshwater malacofauna may be 20–25% lower than it was determined on the basis of the traditional system. Some implications of this outcome for the biogeography of the Beringian freshwater fauna are discussed. 相似文献
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Boris R. Krasnov Sonja Matthee Marcela Lareschi Natalia P. Korallo‐Vinarskaya Maxim V. Vinarski 《Oikos》2010,119(1):120-128
We studied patterns of species co-occurrence in communities of ectoparasitic arthropods (ixodid ticks, mesostigmate mites and fleas) harboured by rodent hosts from South Africa ( Rhabdomys pumilio ), South America ( Scapteromys aquaticus and Oxymycterus rufus ) and west Siberia ( Apodemus agrarius , Microtus gregalis , Microtus oeconomus and Myodes rutilus ) using null models. We compared frequencies of co-occurrences of parasite species or higher taxa across host individuals with those expected by chance. When non-randomness of parasite co-occurrences was detected, positive but not negative co-occurrences of parasite species or higher taxa prevailed (except for a single sample of mesostigmate mites from O. rufus ). Frequency of detection of non-randomness of parasite co-occurrences differed among parasite taxa, being higher in fleas and lower in mites and ticks. This frequency differed also among host species independent of parasite taxon, being highest in Microtus species and lowest in O. rufus and S. aquaticus . We concluded that the pattern of species co-occurrence in ectoparasite communities on rodent hosts is predominantly positive, depends on life history of parasites and may be affected to a great extent by life history of a host. 相似文献