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Hannu Ylonen - One of the best experts on this subject based on the ideXlab platform.
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long term fitness benefits of polyandry in a small mammal the bank vole Clethrionomys glareolus
Proceedings of The Royal Society B: Biological Sciences, 2008Co-Authors: Ines Klemme, Hannu Ylonen, Jana A EccardAbstract:Polyandry, i.e. mating with multiple males within one reproductive event, is a common female mating strategy but its adaptive function is often unclear. We tested whether polyandrous females gain genetic benefits by comparing fitness traits of monandrous (mated twice with a single male) and polyandrous (mated twice with two different males) female bank voles Clethrionomys glareolus. We raised the offspring in the laboratory until adulthood and measured their body size, before releasing them to outdoor enclosures to overwinter. At the onset of the breeding season in the following spring, we found that offspring of polyandrous females performed significantly better at reproduction than those of monandrous females. This was mainly due to sons of polyandrous females producing significantly more offspring than those of monandrous females. No significant differences were found for offspring body mass or winter survival between the two treatments. Our results appear to provide evidence that bank vole females gain long-term benefits from polyandry.
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Reproductive success of male bank voles (Clethrionomys glareolus): the effect of operational sex ratio and body size
Behavioral Ecology and Sociobiology, 2007Co-Authors: Ines Klemme, Hannu Ylonen, Jana A EccardAbstract:The operational sex ratio (OSR) may influence the intensity of competition for mates and mate choice and is therefore thought to be a major factor predicting the intensity and direction of sexual selection. We studied the opportunity for sexual selection, i.e., the variance in male reproductive success and the direction and intensity of sexual selection on male body mass in bank vole ( Clethrionomys glareolus ) enclosure populations with experimentally manipulated sex ratios. The opportunity for sexual selection was high among male-biased OSRs and decreased towards female-biased OSRs. Paradoxically, selection for large male body mass was strongest in female-biased OSRs and also considerable at intermediate OSRs, whereas at male-biased OSRs, only a weak relationship between male size and reproductive success was found. Litters in male-biased OSRs were more likely to be sired by multiple males than litters in female-biased OSRs. Our results suggest that the intensity and direction of sexual selection in males differs among different OSRs. Although the direction of sexual selection on male body mass was opposite than predicted, large body mass can be favored by sexual selection. Naturally varying OSRs may therefore contribute to maintain variation in male sexually selected traits.
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do female bank voles Clethrionomys glareolus mate multiply to improve on previous mates
Behavioral Ecology and Sociobiology, 2006Co-Authors: Ines Klemme, Jana A Eccard, Hannu YlonenAbstract:Contrary to classical sexual selection theories, females of many taxa mate with multiple males during one reproductive cycle. In this study, we conducted an experiment on the “trade-up hypothesis”, which proposes that females remate if a subsequently encountered male is potentially superior to previous mates to maximize the genetic quality of their offspring. We presented bank vole females (Clethrionomys glareolus) sequentially with two males of known dominance rank in different orders, i.e., either first subordinate and second dominant, first dominant and second subordinate, or two males that were equal in dominance (high ranking) and observed their mating behavior. We found that 92% of the females mated multiply and did not base their remating decision on male social status. Therefore, polyandry cannot be explained by the “trade-up hypothesis” based on dominance rank in this species. However, we found that dominant males sired significantly more offspring than subordinate males. This varied according to mating order: dominant males sired more offspring when they were second than when they were first. Moreover, litter sizes were significantly smaller when the dominant male was first (smallest relative success of dominant males) compared to litter sizes when mating order was reversed or both males equal in status. Our results suggest that even though multimale mating includes males that are of poorer quality and thus potentially decreases the fitness of offspring, most of a female’s offspring are sired by dominant males. Whether this is due to cryptic female choice, sperm competition, or a combination of both, remains to be tested.
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WEASELS’ (MUSTELA NIVALIS NIVALIS) PREFERENCE FOR OLFACTORY CUES OF THE VOLE (Clethrionomys glareolus)
Ecology, 2003Co-Authors: Hannu Ylonen, Jana A Eccard, Janne Sundell, Raisa Tiilikainen, Taina J. HorneAbstract:Many studies on life history strategies of small mammals under predation risk are based on assumptions that mammalian predators use scent marking from prey in searching and hunting. This is especially true for small mustelids hunting in the tunnels and cavities of their prey. It is assumed that weasels use the estrous signs of female voles as hunting cues, which exposes such females to a more pronounced risk of predation. We studied the preferences of 57 least weasels (Mustela nivalis nivalis) toward odor cues from four different reproductive categories of the bank vole (Clethrionomys glareolus). In the first experiment, weasels selected clearly for vole odors over clean bedding in a Y-maze arena. The second experiment demonstrated that there was no difference in weasel preference between estrous and pregnant or lactating females. Thirdly, there was no preference for odors from dominant vs. subordinate males. Finally, we offered weasels a dyadic choice between olfactory signs of six possible combinations ...
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heritabilities of dominance related traits in male bank voles Clethrionomys glareolus
Evolution, 1998Co-Authors: Taina J. Horne, Hannu YlonenAbstract:A number of studies have shown that in several animal species females prefer dominant males as mating partners, but fewer attempts have been made to measure possible indirect benefits of this choice. One reason for this may be that, even though dominance is a widely used concept, the definition of dominance still remains controversial. Furthermore, defining and measuring the heritability of social behaviors is problematic because they are not individual traits but, by definition, involve interactions between at least two individuals. In this study we estimated heritabilities and coefficients of additive genetic variances (CVA) for male traits that are closely associated with dominance and female mating preferences in bank voles (Clethrionomys glareolus). The heritability values were estimated using father- offspring regression. All heritability estimates were relatively high ranging from 0.531 (urine marking) to 0.767 (preputial glands). The CVA-values indicated high levels of additive genetic variance especially in the characters most closely related to dominance: the weight of preputial glands and urine marking behavior. All phenotypic correlations among the traits measured were significantly positive and the genetic correlations were of similar magnitude as the corresponding phenotypic counterparts. Even though heritabilities may be lower in the natural environment than under controlled laboratory conditions, our results suggest that characters closely related to dominance may be at least partly genetically determined.
Petr Kotlik - One of the best experts on this subject based on the ideXlab platform.
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the complete mitochondrial genome of the bank vole Clethrionomys glareolus rodentia arvicolinae
Mitochondrial DNA, 2016Co-Authors: Karolina Bendova, Silvia Markova, Jeremy B Searle, Petr KotlikAbstract:We present the first complete sequence of the bank vole (Clethrionomys glareolus) mitochondrial genome (GenBank accession no. KF918859). The bank vole mitogenome is 16,353 base pairs long and shows the gene content, genome architecture and gene strand asymmetry typical for mammals. The sequence provides an important new genomic resource for the bank vole, which is a popular study species in ecological and evolutionary research.
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mapping 3 transcript ends in the bank vole Clethrionomys glareolus mitochondrial genome with rna seq
BMC Genomics, 2015Co-Authors: Silvia Markova, Jeremy B Searle, Karolina Filipi, Petr KotlikAbstract:Although posttranscriptional modification of mitochondrial (mt) transcripts plays key roles in completion of the coding information and in the expression of mtDNA-encoded genes, there is little experimental evidence on the polyadenylation status and the location of mt gene poly(A) sites for non-human mammals. Poly(A)-enriched RNA-Seq reads collected for two wild-caught bank voles (Clethrionomys glareolus) were mapped to the complete mitochondrial genome of that species. Transcript polyadenylation was detected as unmapped adenine residues at the ends of the mapped reads. Where the tRNA punctuation model applied, there was the expected polyadenylation, except for the nad5 transcript, whose polyadenylated 3′ end is at an intergenic sequence/cytochrome b boundary. As in human, two pairs of bank vole genes, nad4l/nad4 and atp8/atp6, are expressed from bicistronic transcripts. TAA stop codons of four bank vole protein-coding genes (nad1, atp6, cox3 and nad4) are incompletely encoded in the DNA and are completed by polyadenylation. This is three genes (nad2, nad3 and cob) less than in human. The bank vole nad2 gene encodes a full stop codon (TAA in one vole and TAG in the other), which is followed by a 2 bp UTR and the gene conforms to the tRNA punctuation model. In contrast, the annotations of the reference mouse and some other rodent mt genomes in GenBank include complete TAG stop codons in both nad1 and nad2, which overlap downstream trnI and trnW, respectively. Thus the RNA-Seq data of bank voles provides a model for stop codons of mt-encoded genes in mammals comparable to humans, but at odds with some of the interpretation based purely on genomic data in mouse and other rodents. This work demonstrates how RNA-Seq data were useful to recover mtDNA transcriptome data in a non-model rodent and to shed more light on mammalian mtDNA transcriptome and post-transcriptional modification. Even though gene content and organisation of mtDNA are strongly conserved among mammals, annotations that neglect the transcriptome may be prone to errors in relation to the stop codons.
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mitogenomic phylogenetics of the bank vole Clethrionomys glareolus a model system for studying end glacial colonization of europe
Molecular Phylogenetics and Evolution, 2015Co-Authors: Karolina Filipi, Silvia Markova, Jeremy B Searle, Petr KotlikAbstract:Abstract We have revisited the mtDNA phylogeny of the bank vole Clethrionomys glareolus based on Sanger and next-generation Illumina sequencing of 32 complete mitochondrial genomes. The bank vole is a key study species for understanding the response of European fauna to the climate change following the Last Glacial Maximum (LGM) and one of the most convincing examples of a woodland mammal surviving in cryptic northern glacial refugia in Europe. The genomes sequenced included multiple representatives of each of the eight bank vole clades previously described based on cytochrome b ( cob ) sequences. All clades with the exception of the Basque – likely a misidentified pseudogene clade – were highly supported in all phylogenetic analyses and the relationships between the clades were resolved with high confidence. Our data extend the distribution of the Carpathian clade, the marker of a northern glacial refugium in the Carpathian Mountains, to include Britain and Fennoscandia (but not adjacent areas of continental Europe). The Carpathian sub-clade that colonized Britain and Fennoscandia had a somewhat different history from the sub-clade currently found in or close to the Carpathians and may have derived from a more north-westerly refugial area. The two bank vole populations that colonized Britain at the end of the last glaciation are for the first time linked with particular continental clades, the first colonists with the Carpathian clade and the second colonists with the western clade originating in a more southerly refugium in the vicinity of the Alps. We however found no evidence that a functional divergence of proteins encoded in the mitochondrial genome promoted the partial genetic replacement of the first colonists by the second colonists detected previously in southern Britain. We did identify one codon site that changed more often and more radically in the tree than expected and where the observed amino acid change may affect the reductase activity of the cytochrome bc 1 complex, but the change was not specific to a particular clade. We also found an excess of radical changes to the primary protein structure for geographically restricted clades from southern Italy and Norway, respectively, possibly related to stronger selective pressure at the latitudinal extremes of the bank vole distribution. However, overall, we find little evidence of pervasive effects of deviation from neutrality on bank vole mtDNA phylogeography.
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A northern glacial refugium for bank voles (Clethrionomys glareolus)
Proceedings of the National Academy of Sciences of the United States of America, 2006Co-Authors: Petr Kotlik, Valérie Deffontaine, Silvia Mascheretti, Jan Zima, Johan Michaux, Jeremy B SearleAbstract:There is controversy and uncertainty on how far north there were glacial refugia for temperate species during the Pleistocene glaciations and in the extent of the contribution of such refugia to present-day populations. We examined these issues using phylogeographic analysis of a European woodland mammal, the bank vole (Clethrionomys glareolus). A Bayesian coalescence analysis indicates that a bank vole population survived the height of the last glaciation (≈25,000–10,000 years B.P.) in the vicinity of the Carpathians, a major central European mountain chain well north of the Mediterranean areas typically regarded as glacial refugia for temperate species. Parameter estimates from the fitted isolation with migration model show that the divergence of the Carpathian population started at least 22,000 years ago, and it was likely followed by only negligible immigration from adjacent regions, suggesting the persistence of bank voles in the Carpathians through the height of the last glaciation. On the contrary, there is clear evidence for gene flow out of the Carpathians, demonstrating the contribution of the Carpathian population to the colonization of Europe after the Pleistocene. These findings are consistent with data from animal and plant fossils recovered in the Carpathians and provide the clearest phylogeographic evidence to date of a northern glacial refugium for temperate species in Europe.
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beyond the mediterranean peninsulas evidence of central european glacial refugia for a temperate forest mammal species the bank vole Clethrionomys glareolus
Molecular Ecology, 2005Co-Authors: Valérie Deffontaine, Jeremy B Searle, Petr Kotlik, Roland Libois, Roger Sommer, Caroline M Nieberding, Emmanuel Paradis, Johan MichauxAbstract:This study details the phylogeographic pattern of the bank vole, Clethrionomys glareolus,a European rodent species strongly associated with forest habitat. We used sequences of 1011 base pairs of the mitochondrial DNA cytochrome b gene from 207 bank voles collected in 62 localities spread throughout its distribution area. Our results reveal the presence of three Mediterranean (Spanish, Italian and Balkan) and three continental (western, eastern and ‘Ural’) phylogroups. The endemic Mediterranean phylogroups did not contribute to the postglacial recolonization of much of the Palaearctic range of species. Instead, the major part of this region was apparently recolonized by bank voles that survived in glacial refugia in central Europe. Moreover, our phylogeographic analyses also reveal differentiated populations of bank voles in the Ural mountains and elsewhere, which carry the mitochondrial DNA of another related vole species, the ruddy vole (Clethrionomys rutilus). In conclusion, this study demonstrates a complex phylogeographic history for a forest species in Europe which is sufficiently adaptable that, facing climate change, survives in relict southern and northern habitats. The high level of genetic diversity characterizing vole populations from parts of central Europe also highlights the importance of such regions asa source of intraspecific genetic biodiversity.
Edward Sinski - One of the best experts on this subject based on the ideXlab platform.
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medium term temporal stability of the helminth component community structure in bank voles Clethrionomys glareolus from the mazury lake district region of poland
Parasitology, 2005Co-Authors: Anna Bajer, Agnieszka Pawelczyk, Jerzy M Behnke, Karolina Kulis, Michal J Sereda, Edward SinskiAbstract:The structure of helminth communities in wild rodents is subject to seasonal variation, and is dependent on host age within years. Although between-year variation has been monitored, seldom has it been assessed rigorously by appropriate multifactorial analysis with potentially confounding factors taken into account. In this study we tested the null hypothesis that despite seasonal, host age and sex effects, helminth communities should show relative stability between years. Over a period of 3 years (1998–2000) we sampled bank vole (Clethrionomys glareolus) populations (total n=250) at 2 points in the year: in spring, at the start of the breeding season, and in autumn, after the cessation of breeding. In spite of seasonal differences and strong age effects, the between-year effects were surprisingly small. Measures of component community structure (Berger- Parker dominance index, the dominant species, S. petrusewiczi) did not vary, or varied only slightly from year to year. The majority of measures of infracommunity structure [Brillouin’s index of diversity, prevalence of all helminths combined, prevalence and abundance of H. mixtum (the most prevalent helminth), mean species richness] did not differ significantly between years when other factors such as age, sex and seasonal variation had been taken into account. Some between-year variations were found (at the component community level, Simpson’s index of diversity ; at the infracommunity level, prevalence and abundance of S. petrusewiczi and abundance of all helminths combined), but even these were modest in comparison to seasonal and age differences, and were primarily attributable to S. petrusewiczi. We conclude that despite dynamic within-year fluctuations, helminth communities in bank voles in this region of Poland show relative stability across years. The sporadic occurrence of individual platyhelminths at low prevalence, makes little difference to the overall structure, which is largely maintained by the key roles played by the dominant intestinal nematodes of bank voles and the rarer species collectively.
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local variation in helminth burdens of bank voles Clethrionomys glareolus from ecologically similar sites temporal stability and relationships with hormone concentrations and social behaviour
Journal of Helminthology, 2003Co-Authors: C J Barnard, Anna Bajer, Jerzy M Behnke, K Kulis, Joanna Gromadzkaostrowska, Malgorzata Stachon, Edward SinskiAbstract:Populations of bank voles (Clethrionomys glareolus) in a fragmented forest habitat in north-east Poland showed local differences in helminth infection intensity, morphometric measures and organ weights that were consistent with differences at the same locations two years previously. Although overall intensities of infection were lower than previously, and there were some differences in the relative intensities of individual helminth species, site differences remained significant and were consistent across replicated subsites. In keeping with site differences in helminth infection and adrenal gland weight and asymmetry, voles at site 1 (high intensity infection) had higher circulating concentrations of corticosterone than those at site 2 (low intensity infection). Since males were sampled outside the breeding season, and thus non-scrotal, testosterone levels were low and did not differ between sites. As previously, voles at site 1 also showed greater hind foot asymmetry. Dyadic interactions between males from the same and different sites in the laboratory showed that males from site 1 were significantly less aggressive, especially when confronted with intruder males from site 2. There was no relationship between aggressiveness and intensity of infection overall or at site 1, but a significant negative relationship emerged at site 2. Aggression thus appeared to be downregulated at the higher intensity site independently of individual levels of infection. Terminal corticosterone concentrations were greater at site 1 and lower among residents that initiated more aggression. While corticosterone concentrations rose over the period of testing, they did not correlate with the amount of aggression initiated or received.
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local variation in endoparasite intensities of bank voles Clethrionomys glareolus from ecologically similar sites morphometric and endocrine correlates
Journal of Helminthology, 2002Co-Authors: C J Arnard, J M Ehnke, Anna Aje, T Race, K Frake, J Osmond, J Dinmore, Edward SinskiAbstract:Much interest has centred recently on the role of adaptive trade-offs between the immune system and other components of life history in determining resistance and parasite intensities among hosts. Steroid hormones, particularly glucocorticoids and sex steroids, provide a plausible mechanism for mediating such trade-offs. A basic assumption behind the hypothesis, however, is that steroid activity will generally correlate with reduced resistance and thus greater parasite intensities. Here, we present some findings from a field study of bank voles (Clethrionomys glareolus ) in which we have looked at associations between parasite intensities, anatomical and morphometric measures relating to endocrine function and life history variation in three local populations inhabiting similar but mutually isolated woodland habitats. In general, sites with greater parasite intensities were those in which male C. glareolus had significantly larger adrenal glands, testes and seminal vesicles for their age and body size. Females also showed a site difference in adrenal gland weight. Some aspects of site-related parasite intensity were associated with asymmetry in adrenal gland weight and hind foot length, which may have reflected developmental effects on glucocorticoid activity.
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variation in the helminth community structure in bank voles Clethrionomys glareolus from three comparable localities in the mazury lake district region of poland
Parasitology, 2001Co-Authors: Jerzy M Behnke, T Race, K Frake, J Osmond, J Dinmore, Anna Bajer, C J Barnard, Daniel Bray, Edward SinskiAbstract:We tested the null hypothesis that populations of hosts trapped in isolated neighbouring locations showing comparable habitat quality, should support similar helminth parasite communities. The study was undertaken in a 2-week period in late summer in NE Poland in a single year, thereby eliminating seasonal and between-year variation in parasite burdens. A total of 139 Clethrionomys glareolus (bank vole) were sampled from 3 forest sites of similar habitat quality. Total species richness was 11 (6 nematodes and 5 cestodes) with 85±6% of the voles carrying at least 1 species and an overall mean species richness of 1±4. At the component community level, the fewest species of helminths were recorded from site 2 (n=6, compared with 9 at each of the other sites), but site 3 had the lowest Berger-Parker Dominance Index and the highest Simpson's Index of Diversity. At the infracommunity level, site 3 had the highest mean no. of helminthspecies}vole, the highest mean Brillouin's Index of Diversity but the lowest mean no. of helminths/vole. Voles from sites 1 and 3 differed in the nematodes that were most common (site 1, Heligmosomum mixtum ± 95%; site 3, Heligmosomoides glareoli ± 79±3%). At site 2 no species exceeded 50% but prevalence of Syphacia petrusewiczi was higher than at the other sites. The prevalence of cestodes was too low to test reliably (12±9%), but the highest prevalence of adult cestodes was recorded at site 1 (22±5%compared with 4±9 and 1±7%for sites 2 and 3 respectively). Host sex did not ifluence infection, but mean species richness increased with age. The different sites were responsible for most of the variation in our data, and the intrinsic factors (sex and age) were less important in shaping the component community structure of helminths. We conclude that even locations in relative close proximity to one another (13±25 km), selected on the basis of similar habitat quality, have rodent populations that differ in their helminth parasite communities, although for reasons other than the factors quantified in the present study.
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factors affecting the component community structure of haemoparasites in bank voles Clethrionomys glareolus from the mazury lake district region of poland
Parasitology, 2001Co-Authors: Anna Bajer, Agnieszka Pawelczyk, Jerzy M Behnke, Francis Gilbert, Edward SinskiAbstract:The prevalence and abundance of infections with haemoparasites were studied over a 3 year period in Clethrionomys glareolus (bank vole, n=420) sampled from forests in the NE of Poland. Total species richness was 5 (Prevalence=Haemobartonella sp. 63.1%, Bartonella grahamii 27.4%, Hepatozoon erhardovae 31.4%, Trypanosoma evotomys 15% and Babesia microti 1.0%) with 81.9% of the voles carrying at least 1 species and a mean infracommunity species richness of 1.4. Variation in species richness was determined primarily by season and year, and the interaction of these factors. The observed frequency distribution of infracommunity species richness did not differ from that predicted by a null model, suggesting that there were no marked associations between the species. Analyses of prevalence and abundance of infection with each species in turn, revealed that overall the principal causes of variation were temporal and seasonal and their interaction, intrinsic factors such as age and sex playing only a minor role. However, the relative importance of specific extrinsic, and rarely intrinsic, factors varied and was distinct for each of the species in the study. Prevalence data revealed 4 sets of 2-way associations between species, mostly varyingly dependent on combinations of intrinsic and extrinsic factors. Analysis of quantitative associations suggested 4 sets of positive 2-way interactions, 3 of which remained after controlling for the effect of extrinsic and intrinsic factors on the abundance of each species, but only one could be unequivocally accepted (Haemobartonella sp. +B. grahamii) after correction for multiple comparisons. These data are discussed in the context of the changing ecological profiles in this region of Eastern Europe and, in a wider context, in relation to current understanding of the factors which shape component community structures of haemoparasites in wild rodents.
Taina J. Horne - One of the best experts on this subject based on the ideXlab platform.
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WEASELS’ (MUSTELA NIVALIS NIVALIS) PREFERENCE FOR OLFACTORY CUES OF THE VOLE (Clethrionomys glareolus)
Ecology, 2003Co-Authors: Hannu Ylonen, Jana A Eccard, Janne Sundell, Raisa Tiilikainen, Taina J. HorneAbstract:Many studies on life history strategies of small mammals under predation risk are based on assumptions that mammalian predators use scent marking from prey in searching and hunting. This is especially true for small mustelids hunting in the tunnels and cavities of their prey. It is assumed that weasels use the estrous signs of female voles as hunting cues, which exposes such females to a more pronounced risk of predation. We studied the preferences of 57 least weasels (Mustela nivalis nivalis) toward odor cues from four different reproductive categories of the bank vole (Clethrionomys glareolus). In the first experiment, weasels selected clearly for vole odors over clean bedding in a Y-maze arena. The second experiment demonstrated that there was no difference in weasel preference between estrous and pregnant or lactating females. Thirdly, there was no preference for odors from dominant vs. subordinate males. Finally, we offered weasels a dyadic choice between olfactory signs of six possible combinations ...
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maternal effort and male quality in the bank vole Clethrionomys glareolus
Proceedings of The Royal Society B: Biological Sciences, 1999Co-Authors: Tuula A Oksanen, Taina J. Horne, Rauno V Alatalo, Esa Koskela, Johanna Mappes, Tapio MappesAbstract:Parental investment in reproduction is adjusted according to potential bene¢ts in terms of oispring survival and/or mating success. If male quality aiects the reproductive success of a female, then females mating with high-quality males should invest more in reproduction. Although the subject has been of general interest, further experimental veri¢cation of the hypothesis is needed.We studied whether female bank voles (Clethrionomys glareolus) adjusted their maternal eiort according to male quality, measured as mating success. To enable the measurement of maternal eiort during nursing separately from male genetic eiects the litters were cross-fostered. Further, the genetic background of male quality was examined. Male quality did not correlate with litter size or oispring size at birth. Oispring growth was positively related to food consumption and milk production of mothers. However, these direct measurements of maternal eiort were independent of male quality. Male mating success appeared to be signi¢cantly heritable indicating that there are genetic bene¢ts. Still, females did not adjust maternal eiort according to the genetic quality of their oispring. We suggest that female bank voles gain signi¢cant genetic bene¢ts from mating with high-quality males whereas they cannot improve their reproductive success by increasing maternal eiort.
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heritabilities of dominance related traits in male bank voles Clethrionomys glareolus
Evolution, 1998Co-Authors: Taina J. Horne, Hannu YlonenAbstract:A number of studies have shown that in several animal species females prefer dominant males as mating partners, but fewer attempts have been made to measure possible indirect benefits of this choice. One reason for this may be that, even though dominance is a widely used concept, the definition of dominance still remains controversial. Furthermore, defining and measuring the heritability of social behaviors is problematic because they are not individual traits but, by definition, involve interactions between at least two individuals. In this study we estimated heritabilities and coefficients of additive genetic variances (CVA) for male traits that are closely associated with dominance and female mating preferences in bank voles (Clethrionomys glareolus). The heritability values were estimated using father- offspring regression. All heritability estimates were relatively high ranging from 0.531 (urine marking) to 0.767 (preputial glands). The CVA-values indicated high levels of additive genetic variance especially in the characters most closely related to dominance: the weight of preputial glands and urine marking behavior. All phenotypic correlations among the traits measured were significantly positive and the genetic correlations were of similar magnitude as the corresponding phenotypic counterparts. Even though heritabilities may be lower in the natural environment than under controlled laboratory conditions, our results suggest that characters closely related to dominance may be at least partly genetically determined.
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female bank voles Clethrionomys glareolus prefer dominant males but what if there is no choice
Behavioral Ecology and Sociobiology, 1996Co-Authors: Taina J. Horne, Hannu YlonenAbstract:Both intra-sexual competition between males and female mate choice have been found to affect mating behaviour in rodents. We studied female choice in the bank vole (Clethrionomys glareolus) under circumstances where male-male competition was excluded and the female could interact and mate freely with the males. Mating behaviour was observed in two situations: (1) the female encountered two males with a clear dominance relationship; and (2) the two males were equal in their social status. In all tests where a female in postpartum oestrus had a choice between males of different social rank she mated with the dominant one. When choosing between an even pair of males there was no difference in the frequency of lordotic responses, mounts or intromissions the female exhibited with either male before mating with one of them. The mean ejaculation latency was significantly longer in the tests with an even pair of males than in the tests where male hierarchy was clear. These results show that bank vole females are able to discriminate males according to their social status and strongly prefer dominant males as mating partners. However, when the females were presented with two equal males, they seemed to be unable to make a choice. The ability to choose the mating partner when the males are clearly different may be an important direct benefit for the female in terms of time saved during mating and thus decreased risk of predation and infanticide.
Jana A Eccard - One of the best experts on this subject based on the ideXlab platform.
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long term fitness benefits of polyandry in a small mammal the bank vole Clethrionomys glareolus
Proceedings of The Royal Society B: Biological Sciences, 2008Co-Authors: Ines Klemme, Hannu Ylonen, Jana A EccardAbstract:Polyandry, i.e. mating with multiple males within one reproductive event, is a common female mating strategy but its adaptive function is often unclear. We tested whether polyandrous females gain genetic benefits by comparing fitness traits of monandrous (mated twice with a single male) and polyandrous (mated twice with two different males) female bank voles Clethrionomys glareolus. We raised the offspring in the laboratory until adulthood and measured their body size, before releasing them to outdoor enclosures to overwinter. At the onset of the breeding season in the following spring, we found that offspring of polyandrous females performed significantly better at reproduction than those of monandrous females. This was mainly due to sons of polyandrous females producing significantly more offspring than those of monandrous females. No significant differences were found for offspring body mass or winter survival between the two treatments. Our results appear to provide evidence that bank vole females gain long-term benefits from polyandry.
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Reproductive success of male bank voles (Clethrionomys glareolus): the effect of operational sex ratio and body size
Behavioral Ecology and Sociobiology, 2007Co-Authors: Ines Klemme, Hannu Ylonen, Jana A EccardAbstract:The operational sex ratio (OSR) may influence the intensity of competition for mates and mate choice and is therefore thought to be a major factor predicting the intensity and direction of sexual selection. We studied the opportunity for sexual selection, i.e., the variance in male reproductive success and the direction and intensity of sexual selection on male body mass in bank vole ( Clethrionomys glareolus ) enclosure populations with experimentally manipulated sex ratios. The opportunity for sexual selection was high among male-biased OSRs and decreased towards female-biased OSRs. Paradoxically, selection for large male body mass was strongest in female-biased OSRs and also considerable at intermediate OSRs, whereas at male-biased OSRs, only a weak relationship between male size and reproductive success was found. Litters in male-biased OSRs were more likely to be sired by multiple males than litters in female-biased OSRs. Our results suggest that the intensity and direction of sexual selection in males differs among different OSRs. Although the direction of sexual selection on male body mass was opposite than predicted, large body mass can be favored by sexual selection. Naturally varying OSRs may therefore contribute to maintain variation in male sexually selected traits.
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do female bank voles Clethrionomys glareolus mate multiply to improve on previous mates
Behavioral Ecology and Sociobiology, 2006Co-Authors: Ines Klemme, Jana A Eccard, Hannu YlonenAbstract:Contrary to classical sexual selection theories, females of many taxa mate with multiple males during one reproductive cycle. In this study, we conducted an experiment on the “trade-up hypothesis”, which proposes that females remate if a subsequently encountered male is potentially superior to previous mates to maximize the genetic quality of their offspring. We presented bank vole females (Clethrionomys glareolus) sequentially with two males of known dominance rank in different orders, i.e., either first subordinate and second dominant, first dominant and second subordinate, or two males that were equal in dominance (high ranking) and observed their mating behavior. We found that 92% of the females mated multiply and did not base their remating decision on male social status. Therefore, polyandry cannot be explained by the “trade-up hypothesis” based on dominance rank in this species. However, we found that dominant males sired significantly more offspring than subordinate males. This varied according to mating order: dominant males sired more offspring when they were second than when they were first. Moreover, litter sizes were significantly smaller when the dominant male was first (smallest relative success of dominant males) compared to litter sizes when mating order was reversed or both males equal in status. Our results suggest that even though multimale mating includes males that are of poorer quality and thus potentially decreases the fitness of offspring, most of a female’s offspring are sired by dominant males. Whether this is due to cryptic female choice, sperm competition, or a combination of both, remains to be tested.
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WEASELS’ (MUSTELA NIVALIS NIVALIS) PREFERENCE FOR OLFACTORY CUES OF THE VOLE (Clethrionomys glareolus)
Ecology, 2003Co-Authors: Hannu Ylonen, Jana A Eccard, Janne Sundell, Raisa Tiilikainen, Taina J. HorneAbstract:Many studies on life history strategies of small mammals under predation risk are based on assumptions that mammalian predators use scent marking from prey in searching and hunting. This is especially true for small mustelids hunting in the tunnels and cavities of their prey. It is assumed that weasels use the estrous signs of female voles as hunting cues, which exposes such females to a more pronounced risk of predation. We studied the preferences of 57 least weasels (Mustela nivalis nivalis) toward odor cues from four different reproductive categories of the bank vole (Clethrionomys glareolus). In the first experiment, weasels selected clearly for vole odors over clean bedding in a Y-maze arena. The second experiment demonstrated that there was no difference in weasel preference between estrous and pregnant or lactating females. Thirdly, there was no preference for odors from dominant vs. subordinate males. Finally, we offered weasels a dyadic choice between olfactory signs of six possible combinations ...