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  • 1.
    Carlsson-Graner, Ulla
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Giles, Barbara
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Thrall, P. H.
    Centre for Plant Biodiversity Research, CSIRO - Plant Industry, GPO Box 1600, Canberra, ACT, 2601, Australia.
    Patterns of disease and host resistance in spatially structured systems2014In: European journal of plant pathology, ISSN 0929-1873, E-ISSN 1573-8469, Vol. 138, no 3, p. 499-511Article in journal (Refereed)
    Abstract [en]

    We use data from species of the anther-smut fungi and the host plants Lychnis alpina and Silene dioica to show that spatial structuring at different scales can influence patterns of disease and host resistance. Patterns of disease and host resistance were surveyed in an archipelago subject to land-uplift where populations of S. dioica constitute an age-structured metapopulation, and in three contrasting areas within the mainland range of L. alpina, where population distributions range from continuous, through patchy but spatially connected to highly isolated demes. In S. dioica, disease levels depend on the age, size and density of local patches and populations. Disease is most predictably found in larger dense host patches and populations of intermediate age, and more frequently goes extinct in small old populations. The rate of local disease spread is affected by the level of host resistance; S. dioica populations showing an increase in disease over time are more susceptible than populations where the disease has remained at low levels. Among-population variation in resistance is driven by founding events and populations remain differentiated due to limited gene flow between islands. As observed in the L. alpina system, when populations are more connected, a greater fraction of populations have disease present. Results from a simulation model argue that, while increased dispersal in connected systems can increase disease spread, it may also favour selection of host resistance which ultimately reduces disease levels within populations. This could explain the observed lower disease prevalence in L. alpina in regions where populations are more continuous.

  • 2.
    Carlsson-Granér, Ulla
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ericson, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Giles, Barbara E.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Plant disease and islands2009In: Encyclopedia of Islands / [ed] Rosemary G. Gillespie and David A. Clague, University of California Press , 2009, p. 748-752Chapter in book (Refereed)
  • 3. Chauvet, S
    et al.
    van der Velde, M
    Imbert, E
    Guillemin, ML
    Mayol, M
    Riba, M
    Smulders, MJM
    Vosman, B
    Ericson, L
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Bijlsma, R
    Giles, BE
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Past and current gene flow in the selfing wind-dispersed species Mycelis muralis in western Europe2004In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 13, no 6, p. 1391-1407Article in journal (Refereed)
    Abstract [en]

    The distribution of genetic diversity in Mycelis muralis, or wall lettuce, was investigated at a European scale using 12 microsatellite markers to infer historical and contemporary forces from genetic patterns. Mycelis muralis has the potential for long-distance seed dispersal by wind, is mainly self-pollinated, and has patchily distributed populations, some of which may show metapopulation dynamics. A total of 359 individuals were sampled from 17 populations located in three regions, designated southern Europe (Spain and France), the Netherlands, and Sweden. At this within-region scale, contemporary evolutionary forces (selfing and metapopulation dynamics) are responsible for high differentiation between populations (0.34 < FST < 0.60) but, contrary to expectation, levels of within-population diversity, estimated by Nei's unbiased expected heterozygosity (HE) (0.24 < HE < 0.68) or analyses of molecular variance (50% of the variation found within-populations), were not low. We suggest that the latter results, which are unusual in selfing species, arise from efficient seed dispersal that counteracts population turnover and thus maintains genetic diversity within populations. At the European scale, northern regions showed lower allelic richness (A = 2.38) than populations from southern Europe (A = 3.34). In light of postglacial colonization hypotheses, these results suggest that rare alleles may have been lost during recolonization northwards. Our results further suggest that mutation has contributed to genetic differentiation between southern and northern Europe, and that Sweden may have been colonized by dispersers originating from at least two different refugia.

  • 4. Drotz, Marcus K.
    et al.
    Brodin, Tomas
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Saura, Anssi
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Giles, Barbara E.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ecotype Differentiation in the Face of Gene Flow within the Diving Beetle Agabus bipustulatus (Linnaeus, 1767) in Northern Scandinavia2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 2, p. e31381-Article in journal (Refereed)
    Abstract [en]

    The repeated occurrence of habitat-specific polyphyletic evolved ecotypes throughout the ranges of widely distributed species implies that multiple, independent and parallel selection events have taken place. Ecological transitions across altitudinal gradients over short geographical distances are often associated with variation in habitat-related fitness, these patterns suggest the action of strong selective forces. Genetic markers will therefore contribute differently to differences between ecotypes in local hybrid zones. Here we have studied the adaptive divergence between ecotypes of the water beetle Agabus bipustulatus along several parallel altitudinal gradients in northern Scandinavia. This water beetle is well known for its remarkable morphological variation associated with mountain regions throughout the western Palaearctic. Two morphological ecotypes are recognised: a montane type with reduced flight muscles and a lowland type with fully developed muscles. Using a multilocus survey of allozyme variation and a morphological analysis with landmark-based morphometrics, across thirty-three populations and seven altitudinal gradients, we studied the local adaptive process of gene flow and selection in detail. Populations were sampled at three different elevations: below, at and above the tree line. The results indicate that the levels of divergence observed between ecotypes in morphology and allele frequencies at alpha-Glycerophosphate dehydrogenase relative to those shown by neutral molecular markers reflects local diversifying selection in situ. Four main lines of evidence are shown here: (1) A repeated morphological pattern of differentiation is observed across all altitudinal transects, with high reclassification probabilities. (2) Allele and genotype frequencies at the alpha-Gpdh locus are strongly correlated with altitude, in sharp contrast to the presumable neutral markers. (3) Genetic differentiation is two to three times higher among populations across the tree line than among populations at or below. (4) Genetic differentiation between ecotypes within independent mountain areas is reflected by different sets of allozymes.

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  • 5.
    Giles, Barbara E.
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Granberg, Åsa
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Carlsson-Granér, Ulla
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Race-specific and spatially variable resistance to Microbotryum violaceum, a systemic anther smut disease in Silene dioica metapopulationsManuscript (Other (popular science, discussion, etc.))
  • 6.
    Granberg, Åsa
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Carlsson-Granér, Ulla
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Arnqvist, Per
    Giles, Barbara E
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Variation in breeding system traits within and among populations of Microbotryum violaceum on Silene dioica2008In: International journal of plant sciences, ISSN 1058-5893, E-ISSN 1537-5315, Vol. 169, no 2, p. 293-303Article in journal (Refereed)
    Abstract [en]

    Breeding systems exert profound effects on the amount and distribution of genetic diversity within and among populations. Knowledge of breeding systems is also important for understanding dynamics between coevolving organisms, e.g., pathogen‐host interactions. Here we study the breeding system of the obligate anther smut Microbotryum violaceum on Silene dioica. Microbotryum violaceum is capable of both inbreeding and outcrossing, but several recent studies on other host races have indicated that automixis via intrapromycelial mating is the predominant breeding system. Compared with conjugations between cells from different meioses, automixis results in slower loss of heterozygosity and faster production of infectious hypha. However, high rates of intrapromycelial matings have been suggested to invoke a fitness cost due to production of fewer infectious dikaryons. Working with single strains under standardized laboratory conditions, we studied traits that could influence the distribution of genetic variability and pathogen fitness. We found that intrapromycelial mating is the dominant conjugation form for M. violaceum var. dioica but that the breeding system varies, partly because of genetic differences, both within and among populations. Further, we did not find the predicted fitness reduction for intrapromycelial matings, suggesting that intrapromycelial mating is a highly favorable breeding system for M. violaceum.

  • 7.
    Granberg, Åsa
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Carlsson-Granér, Ulla
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Giles, Barbara E.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Genetic architecture of biochemical resistance to the anther smut Microbotryum violaceum in Silene dioicaManuscript (Other (popular science, discussion, etc.))
  • 8.
    Granberg, Åsa
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Carlsson-Granér, Ulla
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Giles, Barbara E.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Neutral gene diversity in the range margins of an obligate fungal pathogen: Microbotryum violaceum on Silene dioicaManuscript (Other (popular science, discussion, etc.))
  • 9.
    Peedu, Elisabet
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Giles, Barbara E.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ingvarsson, Pär K.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Genetic diversity and differentiation in a Silene dioica metapopulationManuscript (preprint) (Other academic)
  • 10.
    Peedu, Elisabet
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ingvarsson, Pär K.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ericson, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Giles, Barbara E.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sex-specific resource allocation, reproductive costs and life-history consequences in dioecious Silene dioica (Caryophyllaceae)Manuscript (preprint) (Other academic)
  • 11.
    Pettersson, Viktoria
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gardfjell, Hans
    Institutionen för Skoglig resursanalys, SLU, Forest resource management, Swedish University of Agricultural Science.
    Ericson, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Giles, Barbara E
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Male and female resposes to florivory in the perennial herb Silene dioicaManuscript (Other academic)
    Abstract [en]

     In dioecious species the two sexes differ in amount and timing of allocation to reproduction and as a consequence we would expect different sex specific responses to equal losses to herbivory. We studied the response of Silene dioica male and female plants to herbivory of two specialist insect herbivores Caryocolum viscariella and Delia criniventris that share the same food resource, the floral stems. We tracked the fates of marked individuals located in nine populations over eight consecutive years in a Bothnian archipelago. We found no differences in survival probabilities between attacked and non-attacked plants or between the sexes. We found that attacked plants of both sexes re-flowered to a higher extent compared to non-attacked plants. However, there was an inter-sexual difference in response to attack. Attacked females tended to re-flower more often than males and therefore showed a stronger compensatory response to this type of herbivore attack. The likely mechanism for this difference is that females in response to attack of floral stems early in season will save more resources than males and that these resources will be retained in the basal rosette to be used for future reproductive events. This suggests a positive effect on plant life time fecundity in females. However, there is also a negative effect of florivory on number of capsules produced as capsule production was halved in attacked compared to non-attacked females. The demographic implications of these direct and indirect effects of florivory remain to be understood.

     

  • 12.
    Pettersson, Viktoria
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gardfjell, Hans
    Institutionen för Skoglig resursanalys, SLU, Forest resource management, Swedish University of Agricultural Science.
    Ericson, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Giles, Barbara E
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Which sex is most sensitive to a sexually transmitted disease?: A case study of the Microbortyum vioalaceum-Silene dioica associationManuscript (Other academic)
    Abstract [en]

     In contrast to the many studies that have addressed whether herbivores discriminate between male and female plants of dioecious plant species, only a few studies have asked whether the two sexes differ in susceptibility to fungal attack. Most of these have dealt with the anther smut Microbotryum violaceum-Silene association and have generally reported a change from male to female biased disease frequencies in parallel to increasing overall disease frequencies. We followed the study system on nine island populations over seven years in a rising Bothnian archipelago. We found an overall pattern that female plants were more diseased than male plants with two exceptions. Disease frequencies were male biased on islands with low disease levels and in one of the seven study years. The change in disease frequencies from male to female bias confirm earlier studies suggesting that the relative contribution of the two components of infection risk, disease encounter and per contact infection probability can vary with population disease level. The change in the proportions of diseased males and females that was observed in one of the study years, followed a year of extreme weather conditions (prolonged drought). Both sexes showed a similar decline in flowering but diseased females decreased more than diseased males. This difference in response can be explained if considering that disease is more resource demanding in females than in males. Except for resources needed for mycelial growth and spore production, in females resources are also needed to restructure their sex expression and produce anthers. Thus in dioecious species traits that are sexually dimorphic are of great importance for understanding the outcome of interactions with natural enemies, including parasitic fungi.

     

  • 13.
    Pettersson, Viktoria
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gardfjell, Hans
    Institutionen för Skoglig resursanalys, SLU, Forest resource management, Swedish University of Agricultural Science.
    Witzell, Johanna
    Institutionen för sydsvensk skogsvetenskap,SLU, Southern swedish forest reserach centre, Swedish University of Agricultural Science.
    Ericson, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Giles, Barbara E
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Rates of insect herbivory on Silene dioica change across primary successional zones.Manuscript (Other academic)
    Abstract [en]

    The strengths and directions of herbivore-host plant interactions are strongly shaped by environmental conditions that also affect a number of plant traits (density, size, nutritional quality). We studied spatio-temporal patterns in attack rates of two specialist herbivores Delia criniventris and Caryocolum viscariella that utilize the same food resource, the floral stems, of their shared host plant Silene dioica across young, intermediate and old successional zones in the primary succession in a Bothinan archipelago. Our data from nine islands collected during seven consecutive years showed that attack rates were consistently higher in the youngest zone and decreased in parallel to progressing succession. This zonal pattern of decreasing attack rates correlated with several plant attributes, a decrease in plant size and nitrogen content, and an increased content of secondary compounds, but not to host plant density. We failed to come up with a simple explanation for the spatial structure with chronic high attack rates in the younger zones. However, the consistent patterns in attack rate suggest that a suite of abiotic and biotic factors interact and reinforce the strength and direction of selection.

  • 14.
    Pettersson, Viktoria
    et al.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Gardfjell, Hans
    Institutionen för Skoglig resursanalys, SLU, Forest resource management, Swedish University of Agricultural Science.
    Witzell, Johanna
    Institutionen för sydsvensk skogsvetenskap,SLU, Southern swedish forest reserach centre, Swedish University of Agricultural Science.
    Ericson, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Giles, Barbara E
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sex-biased herbivory in Silene dioica.: Which sex is the better resource?Manuscript (Other academic)
    Abstract [en]

    In cases when sexual dimorphic traits form the target resource of a particular herbivore we would expect the herbivore to select the best resource. We studied the interaction between to specialist insect herbivores Delia criniventris and Caryocolum viscariella that share the same food resource, the floral stems, of their host plant the perennial and dioecious herb, Silene dioica. We studied the interaction on nine islands in a Bothinan archipelago over seven consecutive years. Both herbivores attacked female plants more than male plants (D. criniventris, 32.8% females, 30.7% males; C. viscariella, 4% females, 2% males). The pattern was consistent over years and islands. We also found a number of sexually dimorphic traits suggesting females to be the better resource. We have presented evidence that female-biased herbivory does occur in dioecious plants and, as with male-biased herbivory, it may occur because herbivores utilise the better resource which will vary depending upon feeding strategy. We conclude that in dioecious species we need identify the dimorphism responsible for the sex sustaining the greatest attack rates and avoid being blinded by the expectation of male herbivory.

  • 15. Riba, Miquel
    et al.
    Mayol, Maria
    Giles, Barbara E.
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Ronce, Ophélie
    Imbert, Eric
    van der Velde, Marco
    Chauvet, Stéphanie
    Lars Ericson, Lars
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. lars.ericson@emg.umu.se.
    Bijlsma, R
    Vosman, Ben
    Smulders, MJM
    Olivieri, Isabelle
    Darwin's wind hypothesis: does it work for plant dispersal in fragmented habitats?2009In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 183, no 3, p. 667-677Article in journal (Refereed)
    Abstract [en]

    Using the wind-dispersed plant Mycelis muralis, we examined how landscape fragmentation affects variation in seed traits contributing to dispersal. Inverse terminal velocity () of field-collected achenes was used as a proxy for individual seed dispersal ability. We related this measure to different metrics of landscape connectivity, at two spatial scales: in a detailed analysis of eight landscapes in Spain and along a latitudinal gradient using 29 landscapes across three European regions. In the highly patchy Spanish landscapes, seed increased significantly with increasing connectivity. A common garden experiment suggested that differences in may be in part genetically based. The was also found to increase with landscape occupancy, a coarser measure of connectivity, on a much broader (European) scale. Finally, was found to increase along a south2013north latitudinal gradient. Our results for M. muralis are consistent with 'Darwin's wind dispersal hypothesis' that high cost of dispersal may select for lower dispersal ability in fragmented landscapes, as well as with the 'leading edge hypothesis' that most recently colonized populations harbour more dispersive phenotypes.

  • 16.
    Ågren, Karin
    et al.
    Umeå University, Faculty of Social Sciences, Umeå Forum for Studies on Law and Society.
    Giles, Barbara
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lindkvist, Marie
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics.
    Akademiska bedömningsuppdrag - ännu en jämställdhetsfälla?: Slutrapport av projektet Kompensation av tid för uppdrag2012Report (Other (popular science, discussion, etc.))
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    akademiska bedömningsuppdrag - ännu en jämställdhetsfälla?
1 - 16 of 16
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