uu.seUppsala University Publications
Change search
Refine search result
1234 51 - 100 of 168
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 51.
    Hallsson, Lára R.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Quantitative Trait Evolution in a Changing Environment in a Seed Beetle2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    During the last decades the climate has been changing more rapidly than in the preceding periods. This is for instance characterized by an increase in temperature. Interestingly, such changes in the environment are not necessarily constant over time as they often show high levels of fluctuation. Organisms are exposed to these changes and respond to them and a recent theoretical model predicts that fluctuations in the environment are important for populations’ response to climate change. The aim of this thesis is to investigate how populations respond to a changing environment, including fluctuations. My thesis is based on the previously mentioned theoretical model and I used a suite of laboratory experiments on the seed beetle Callsosobruchus maculatus, to test the model predictions in a quantitative genetic framework. First, I assessed the genetic architecture of several life history and morphological traits in order to verify that there is sufficient additive genetic variation for the population to respond to changes in the environment. Second, I tested the detailed model predictions explicitly, by investigating whether different types of environmental fluctuations matter for a population’s response. Third, I investigated changes in quantitative genetic variation after i) a rapid shift in temperature and ii) long term selection under increasing temperature including fluctuations. Fourth, I concentrated on sex differences in response to temperature, and finally, I assessed the relative importance of genetic and nongenetic inheritance for traits that differ in their plastic response to a change in the environment. I found that environmental fluctuations are highly important for a population’s response to environmental change. I could detect changes in a set of quantitative genetic parameters, suggesting that a population’s potential to respond to selection, environmental sensitivity and the evolution of phenotypic plasticity are affected by the selective past. I also found that sexes differ in additive genetic variation and plasticity and that parental effects may play an important role in the evolutionary process. Therefore, future studies would benefit greatly from considering details of the selective past and especially environmental fluctuations during attempts to predict how populations respond to a changing environment, particularly with regards to climate change.

    List of papers
    1. Sex specific genetic variances in life history and morphological traits ofthe seed beetle C. maculatus
    Open this publication in new window or tab >>Sex specific genetic variances in life history and morphological traits ofthe seed beetle C. maculatus
    2012 (English)In: Ecology and Evolution, ISSN 2045-7758, Vol. 2, no 1, p. 128-138Article in journal (Refereed) Published
    Abstract [en]

    Knowledge of heritability and genetic correlations are of central importance in the study ofadaptive trait evolution and genetic constraints. We use a paternal half-sib-full-sib breeding designto investigate the genetic architecture of three life history and morphological traits in the seed beetle, Callosobruchus maculatus. Heritability was significant for all traits under observation andgenetic correlations between traits (rA) were low. Interestingly we found substantial sex-specificgenetic effects and low genetic correlations between sexes (rMF) in traits that are only moderately(weight at emergence) to slightly (longevity) sexually dimorphic. Furthermore we found anincreased sire (s2sire) compared to dam (s2dam) variance component within trait and sex. Our resultshighlight that the genetic architecture even of the same trait should not be assumed to be the samefor males and females. Furthermore it raises the issue of the presence of unnoticed environmental effects that may inflate estimates of heritability. Overall, our study stresses the fact that estimatesof quantitative genetic parameters are not only population, time, environment but also sex specific.Thus, extrapolation between sexes and studies should be treated with caution.

    Keywords
    additive genetic variance, genetic correlation, breeding design, sex specific genetic effect, sexual dimorphism
    National Category
    Evolutionary Biology
    Research subject
    Animal Ecology
    Identifiers
    urn:nbn:se:uu:diva-159275 (URN)10.1002/ece3.56 (DOI)000312442000010 ()
    Available from: 2011-09-26 Created: 2011-09-26 Last updated: 2013-01-24Bibliographically approved
    2. The colour of noise matters for the response of a population to environmental change
    Open this publication in new window or tab >>The colour of noise matters for the response of a population to environmental change
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Recent models predict that the pattern of stochastic fluctuations (noise) matters for theevolutionary response to environmental change. In this study we test predictions from a recenttheoretical model in a laboratory experiment using the seed beetle Callosobruchus maculatus as amodel organism. Populations were exposed to different regimes of temperature increase; withoutnoise and with noise with no temporal autocorrelation (white noise) and very high temporalautocorrelation (red noise) over 18 generations. Developmental time decreased in the treatmentwith white noise fluctuation, but not in the treatment without noise or with red noise fluctuation,compared to the control lines. The main conclusions is, that the pattern of environmentalstochasticity is important for the evolutionary response of a population to a changing environmentas predicted by model simulations.

    Keywords
    environmental noise, changing environment, life-history traits, seed beetle, empirical evidence
    National Category
    Evolutionary Biology
    Research subject
    Animal Ecology
    Identifiers
    urn:nbn:se:uu:diva-159278 (URN)
    Available from: 2011-09-26 Created: 2011-09-26 Last updated: 2018-06-26
    3. Selection in a fluctuating environment leads to decreased genetic variation and facilitates the evolution of phenotypic plasticity
    Open this publication in new window or tab >>Selection in a fluctuating environment leads to decreased genetic variation and facilitates the evolution of phenotypic plasticity
    2012 (English)In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, no 7, p. 1275-1290Article in journal (Refereed) Published
    Abstract [en]

    Changes in the environment are expected to induce changes in the quantitative genetic variation, which influences the ability of a population to adapt to environmental change. Furthermore, environmental changes are not constant in time, but fluctuate. Here, we investigate the effect of rapid, continuous and/or fluctuating temperature changes in the seed beetle Callosobruchus maculatus, using an evolution experiment followed by a split-brood experiment. In line with expectations, individuals responded in a plastic way and had an overall higher potential to respond to selection after a rapid change in the environment. After selection in an environment with increasing temperature, plasticity remained unchanged (or decreased) and environmental variation decreased, especially when fluctuations were added; these results were unexpected. As expected, the genetic variation decreased after fluctuating selection. Our results suggest that fluctuations in the environment have major impact on the response of a population to environmental change; in a highly variable environment with low predictability, a plastic response might not be beneficial and the response is genetically and environmentally canalized resulting in a low potential to respond to selection and low environmental sensitivity. Interestingly, we found greater variation for phenotypic plasticity after selection, suggesting that the potential for plasticity to evolve is facilitated after exposure to environmental fluctuations. Our study highlights that environmental fluctuations should be considered when investigating the response of a population to environmental change.

    Keywords
    canalization, environmental change, environmental sensitivity, experimental evolution, fluctuating temperature, gene by environment interaction, genetic correlation, genetic variation, insects, phenotypic plasticity
    National Category
    Evolutionary Biology
    Research subject
    Animal Ecology
    Identifiers
    urn:nbn:se:uu:diva-159279 (URN)10.1111/j.1420-9101.2012.02512.x (DOI)000305130800005 ()
    Available from: 2011-09-26 Created: 2011-09-26 Last updated: 2017-12-08Bibliographically approved
    4. Selection in a fluctuating environment and the evolution of sexual dimorphism in the seed beetle Callosobruchus maculatus
    Open this publication in new window or tab >>Selection in a fluctuating environment and the evolution of sexual dimorphism in the seed beetle Callosobruchus maculatus
    2012 (English)In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, no 8, p. 1564-1575Article in journal (Refereed) Published
    Abstract [en]

    Sexual dimorphism can be affected by environmental variables such as temperature. There are two hypotheses regarding sex differences in plasticity in a changing environment: the adaptivecanalization hypothesis, and the condition–dependence hypothesis. Here we use a quantitativegenetic framework to test these hypotheses and to investigate both immediate changes in, and theevolution of, sexual dimorphism in response to a changing environment (with and withoutfluctuations). We found a decreased sexual size dimorphism in higher temperature and femalesresponded more plastically than males, supporting the condition dependence hypothesis. However,selection in a fluctuating environment can alter sex-specific patterns of genetic and environmentalvariation, indicating support for the adaptive canalization hypothesis. Also, genetic correlationsbetween sexes (rMF) were affected by fluctuating selection, suggesting a facilitated independent evolution of the sexes. Thus, the selective past of a population is highly important for theunderstanding of the evolutionary dynamics of sexual dimorphism.

    Keywords
    Environmental change, genetic variance, experimental evolution, split brood experiment, sex-specific plasticity, sex-specific environmental sensitivity, insects, condition dependency, genetic correlations
    National Category
    Evolutionary Biology
    Research subject
    Animal Ecology
    Identifiers
    urn:nbn:se:uu:diva-159280 (URN)10.1111/j.1420-9101.2012.02541.x (DOI)000306402800011 ()22594940 (PubMedID)
    Available from: 2011-09-26 Created: 2011-09-26 Last updated: 2017-12-08Bibliographically approved
    5. The relative importance of genetic and nongenetic inheritance in traits of varying degree of plasticity in Callosobruchus maculatus
    Open this publication in new window or tab >>The relative importance of genetic and nongenetic inheritance in traits of varying degree of plasticity in Callosobruchus maculatus
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Both genetic and nongenetic mechanisms of inheritance are important in the study of a trait’sresponse to environmental change. Here we address the question of whether the relativeimportance of these mechanisms is related to the degree of trait plasticity. We investigate theinfluence of additive genetic effects and non genetic parental effects in traits that differ in theirdegree of plasticity. We predicted that more plastic traits will be more amenable to parentaleffects, and genetic variation/covariance will be more difficult to detect. Our findings are in linewith predictions. We suggest that environment dependent parental effects may influence theevolution of a highly plastic trait to a greater extent than traits with low degrees of plasticity.Hence, due to difficulties in detecting genetic variance and covariances and the potential influenceof environment dependent parental effects on heritability, our ability to predict evolutionarychange in highly plastic traits may be limited.

    Keywords
    Plasticity, genetic variation, parental effects, host quality, seed beetle
    National Category
    Evolutionary Biology
    Research subject
    Animal Ecology
    Identifiers
    urn:nbn:se:uu:diva-159281 (URN)
    Available from: 2011-09-26 Created: 2011-09-26 Last updated: 2016-04-19
  • 52.
    Hallsson, Lára R.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Bjorklund, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    The colour of noise matters for the response of a population to environmental changeManuscript (preprint) (Other academic)
    Abstract [en]

    Recent models predict that the pattern of stochastic fluctuations (noise) matters for theevolutionary response to environmental change. In this study we test predictions from a recenttheoretical model in a laboratory experiment using the seed beetle Callosobruchus maculatus as amodel organism. Populations were exposed to different regimes of temperature increase; withoutnoise and with noise with no temporal autocorrelation (white noise) and very high temporalautocorrelation (red noise) over 18 generations. Developmental time decreased in the treatmentwith white noise fluctuation, but not in the treatment without noise or with red noise fluctuation,compared to the control lines. The main conclusions is, that the pattern of environmentalstochasticity is important for the evolutionary response of a population to a changing environmentas predicted by model simulations.

  • 53.
    Hallsson, Lára R.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Björklund, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Selection in a fluctuating environment and the evolution of sexual dimorphism in the seed beetle Callosobruchus maculatus2012In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, no 8, p. 1564-1575Article in journal (Refereed)
    Abstract [en]

    Sexual dimorphism can be affected by environmental variables such as temperature. There are two hypotheses regarding sex differences in plasticity in a changing environment: the adaptivecanalization hypothesis, and the condition–dependence hypothesis. Here we use a quantitativegenetic framework to test these hypotheses and to investigate both immediate changes in, and theevolution of, sexual dimorphism in response to a changing environment (with and withoutfluctuations). We found a decreased sexual size dimorphism in higher temperature and femalesresponded more plastically than males, supporting the condition dependence hypothesis. However,selection in a fluctuating environment can alter sex-specific patterns of genetic and environmentalvariation, indicating support for the adaptive canalization hypothesis. Also, genetic correlationsbetween sexes (rMF) were affected by fluctuating selection, suggesting a facilitated independent evolution of the sexes. Thus, the selective past of a population is highly important for theunderstanding of the evolutionary dynamics of sexual dimorphism.

  • 54.
    Hallsson, Lára R.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Björklund, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Selection in a fluctuating environment leads to decreased genetic variation and facilitates the evolution of phenotypic plasticity2012In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, no 7, p. 1275-1290Article in journal (Refereed)
    Abstract [en]

    Changes in the environment are expected to induce changes in the quantitative genetic variation, which influences the ability of a population to adapt to environmental change. Furthermore, environmental changes are not constant in time, but fluctuate. Here, we investigate the effect of rapid, continuous and/or fluctuating temperature changes in the seed beetle Callosobruchus maculatus, using an evolution experiment followed by a split-brood experiment. In line with expectations, individuals responded in a plastic way and had an overall higher potential to respond to selection after a rapid change in the environment. After selection in an environment with increasing temperature, plasticity remained unchanged (or decreased) and environmental variation decreased, especially when fluctuations were added; these results were unexpected. As expected, the genetic variation decreased after fluctuating selection. Our results suggest that fluctuations in the environment have major impact on the response of a population to environmental change; in a highly variable environment with low predictability, a plastic response might not be beneficial and the response is genetically and environmentally canalized resulting in a low potential to respond to selection and low environmental sensitivity. Interestingly, we found greater variation for phenotypic plasticity after selection, suggesting that the potential for plasticity to evolve is facilitated after exposure to environmental fluctuations. Our study highlights that environmental fluctuations should be considered when investigating the response of a population to environmental change.

  • 55.
    Hallsson, Lára R.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Björklund, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Sex specific genetic variances in life history and morphological traits ofthe seed beetle C. maculatus2012In: Ecology and Evolution, ISSN 2045-7758, Vol. 2, no 1, p. 128-138Article in journal (Refereed)
    Abstract [en]

    Knowledge of heritability and genetic correlations are of central importance in the study ofadaptive trait evolution and genetic constraints. We use a paternal half-sib-full-sib breeding designto investigate the genetic architecture of three life history and morphological traits in the seed beetle, Callosobruchus maculatus. Heritability was significant for all traits under observation andgenetic correlations between traits (rA) were low. Interestingly we found substantial sex-specificgenetic effects and low genetic correlations between sexes (rMF) in traits that are only moderately(weight at emergence) to slightly (longevity) sexually dimorphic. Furthermore we found anincreased sire (s2sire) compared to dam (s2dam) variance component within trait and sex. Our resultshighlight that the genetic architecture even of the same trait should not be assumed to be the samefor males and females. Furthermore it raises the issue of the presence of unnoticed environmental effects that may inflate estimates of heritability. Overall, our study stresses the fact that estimatesof quantitative genetic parameters are not only population, time, environment but also sex specific.Thus, extrapolation between sexes and studies should be treated with caution.

  • 56.
    Hallsson, Lára R.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Chenoweth, Stephen F.
    School of Integrative Biology, University of Queensland, Brisbane, QLD 4072, Australia.
    Bonduriansky, Russell
    Evolution and Ecology Research Centre and School of Biological, Earth, and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.
    The relative importance of genetic and nongenetic inheritance in traits of varying degree of plasticity in Callosobruchus maculatusManuscript (preprint) (Other academic)
    Abstract [en]

    Both genetic and nongenetic mechanisms of inheritance are important in the study of a trait’sresponse to environmental change. Here we address the question of whether the relativeimportance of these mechanisms is related to the degree of trait plasticity. We investigate theinfluence of additive genetic effects and non genetic parental effects in traits that differ in theirdegree of plasticity. We predicted that more plastic traits will be more amenable to parentaleffects, and genetic variation/covariance will be more difficult to detect. Our findings are in linewith predictions. We suggest that environment dependent parental effects may influence theevolution of a highly plastic trait to a greater extent than traits with low degrees of plasticity.Hence, due to difficulties in detecting genetic variance and covariances and the potential influenceof environment dependent parental effects on heritability, our ability to predict evolutionarychange in highly plastic traits may be limited.

  • 57. Haugen, I. M. Aalberg
    et al.
    Berger, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Gotthard, K.
    The evolution of alternative developmental pathways: footprints of selection on life-history traits in a butterfly2012In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, no 7, p. 1377-1388Article in journal (Refereed)
    Abstract [en]

    Developmental pathways may evolve to optimize alternative phenotypes across environments. However, the maintenance of such adaptive plasticity under relaxed selection has received little study. We compare the expression of life-history traits across two developmental pathways in two populations of the butterfly Pararge aegeria where both populations express a diapause pathway but one never expresses direct development in nature. In the population with ongoing selection on both pathways, the difference between pathways in development time and growth rate was larger, whereas the difference in body size was smaller compared with the population experiencing relaxed selection on one pathway. This indicates that relaxed selection on the direct pathway has allowed life-history traits to drift towards values associated with lower fitness when following this pathway. Relaxed selection on direct development was also associated with a higher degree of genetic variation for protandry expressed as within-family sexual dimorphism in growth rate. Genetic correlations for larval growth rate across sexes and pathways were generally positive, with the notable exception of correlation estimates that involved directly developing males of the population that experienced relaxed selection on this pathway. We conclude that relaxed selection on one developmental pathway appears to have partly disrupted the developmental regulation of life-history trait expression. This in turn suggests that ongoing selection may be responsible for maintaining adaptive developmental regulation along alternative developmental pathways in these populations.

  • 58.
    Hotzy, Cosima
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Polak, Michal
    Rönn, Johanna L.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Arnqvist, Goran
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Phenotypic Engineering Unveils the Function of Genital Morphology2012In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 22, no 23, p. 2258-2261Article in journal (Refereed)
    Abstract [en]

    The rapidly evolving and often extraordinarily complex appearance of male genital morphology of internally fertilizing animals has been recognized for centuries [1]. Postcopulatory sexual selection is regarded as the likely evolutionary engine of this diversity [2], but direct support for this hypothesis is limited. We used two complementary approaches, evolution through artificial selection and microscale laser surgery, to experimentally manipulate genital morphology in an insect model system. We then assessed the competitive fertilization success of these phenotypically manipulated males and studied the fate of their ejaculate in females using high-resolution radioisotopic labeling of ejaculates. Males with longer genital spines were more successful in gaining fertilizations, providing experimental evidence that male genital morphology influences success in postcopulatory reproductive competition. Furthermore, a larger proportion of the ejaculate moved from the reproductive tract into the female body following mating with males with longer spines, suggesting that genital spines increase the rate at which seminal fluid passes into the female hemolymph. Our results show that genital morphology affects male competitive fertilization success and imply that sexual selection on genital morphology may be mediated in part through seminal fluid [3].

  • 59.
    Husby, Arild
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Gustafsson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Qvarnström, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Low Genetic Variance in the Duration of the Incubation Period in a Collared Flycatcher (Ficedula albicollis) Population2012In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 179, no 1, p. 132-136Article in journal (Refereed)
    Abstract [en]

    The avian incubation period is associated with high energetic costs and mortality risks suggesting that there should be strong selection to reduce the duration to the minimum required for normal offspring development. Although there is much variation in the duration of the incubation period across species, there is also variation within species. It is necessary to estimate to what extent this variation is genetically determined if we want to predict the evolutionary potential of this trait. Here we use a long-term study of collared flycatchers to examine the genetic basis of variation in incubation duration. We demonstrate limited genetic variance as reflected in the low and nonsignificant additive genetic variance, with a corresponding heritability of 0.04 and coefficient of additive genetic variance of 2.16. Any selection acting on incubation duration will therefore be inefficient. To our knowledge, this is the first time heritability of incubation duration has been estimated in a natural bird population.

  • 60.
    Husby, Arild
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Hille, Sabine M.
    Visser, Marcel E.
    Testing Mechanisms of Bergmann's Rule: Phenotypic Decline but No Genetic Change in Body Size in Three Passerine Bird Populations2011In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 178, no 2, p. 202-213Article in journal (Refereed)
    Abstract [en]

    Bergmann's rule predicts a decrease in body size with increasing temperature and has much empirical support. Surprisingly, we know very little about whether "Bergmann size clines" are due to a genetic response or are a consequence of phenotypic plasticity. Here, we use data on body size (mass and tarsus length) from three long-term (1979-2008) study populations of great tits (Parus major) that experienced a temperature increase to examine mechanisms behind Bergmann's rule. We show that adult body mass decreased over the study period in all populations and that tarsus length increased in one population. Both body mass and tarsus length were heritable and under weak positive directional selection, predicting an increase, rather than a decrease, in body mass. There was no support for microevolutionary change, and thus the observed declines in body mass were likely a result of phenotypic plasticity. Interestingly, this plasticity was not in direct response to temperature changes but seemed to be due to changes in prey dynamics. Our results caution against interpreting recent phenotypic body size declines as adaptive evolutionary responses to temperature changes and highlight the importance of considering alternative environmental factors when testing size clines.

  • 61.
    Husby, Arild
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Nussey, Dan H.
    Visser, Marcel E.
    Wilson, Alastair J.
    Sheldon, Ben C.
    Kruuk, Loeske E. B.
    Contrasting patterns of phenotypic plasticity in reproductive traits in two great tit (Parus major) populations2010In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 64, no 8, p. 2221-2237Article in journal (Refereed)
    Abstract [en]

    Phenotypic plasticity is an important mechanism via which populations can respond to changing environmental conditions, but we know very little about how natural populations vary with respect to plasticity. Here we use random-regression animal models to understand the multivariate phenotypic and genetic patterns of plasticity variation in two key life-history traits, laying date and clutch size, using data from long-term studies of great tits in The Netherlands (Hoge Veluwe [HV]) and UK (Wytham Woods [WW]). We show that, while population-level responses of laying date and clutch size to temperature were similar in the two populations, between-individual variation in plasticity differed markedly. Both populations showed significant variation in phenotypic plasticity (IxE) for laying date, but IxE was significantly higher in HV than in WW. There were no significant genotype-by-environment interactions (GxE) for laying date, yet differences in GxE were marginally nonsignificant between HV and WW. For clutch size, we only found significant IxE and GxE in WW but no significant difference between populations. From a multivariate perspective, plasticity in laying date was not correlated with plasticity in clutch size in either population. Our results suggest that generalizations about the form and cause of any response to changing environmental conditions across populations may be difficult.

  • 62.
    Husby, Arild
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Visser, Marcel E.
    Kruuk, Loeske E. B.
    Speeding Up Microevolution: The Effects of Increasing Temperature on Selection and Genetic Variance in a Wild Bird Population2011In: PLoS biology, ISSN 1544-9173, E-ISSN 1545-7885, Vol. 9, no 2, p. e1000585-Article in journal (Refereed)
    Abstract [en]

    The amount of genetic variance underlying a phenotypic trait and the strength of selection acting on that trait are two key parameters that determine any evolutionary response to selection. Despite substantial evidence that, in natural populations, both parameters may vary across environmental conditions, very little is known about the extent to which they may covary in response to environmental heterogeneity. Here we show that, in a wild population of great tits (Parus major), the strength of the directional selection gradients on timing of breeding increased with increasing spring temperatures, and that genotype-by-environment interactions also predicted an increase in additive genetic variance, and heritability, of timing of breeding with increasing spring temperature. Consequently, we therefore tested for an association between the annual selection gradients and levels of additive genetic variance expressed each year; this association was positive, but nonsignificant. However, there was a significant positive association between the annual selection differentials and the corresponding heritability. Such associations could potentially speed up the rate of micro-evolution and offer a largely ignored mechanism by which natural populations may adapt to environmental changes.

  • 63.
    Häubner, Norbert
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Ecological Botany.
    Tallmark, Bo
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Snoeijs, Pauli
    Department of Systems Ecology, Stockholm University.
    Phytoplankton biomass controls tocopherol concentrations in Baltic Sea zooplanktonIn: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599Article in journal (Refereed)
    Abstract [en]

    Nearly all organisms are constantly exposed to oxidative threat, because every reaction where oxygen is involved gives rise to oxidants. Efficient protection is provided by antioxidants. Vitamin E (tocopherol) is an essential plant-derived antioxidant and poorly studied so far in marine food webs. In 2004 and 2005 eight offshore expeditions were conducted in the Baltic Sea to explore the dynamics of α-tocopherol in the pelagic food web. In order to analyze tocopherol production and transition to the next food web level, two plankton size classes were sampled; <100 µm (dominated by phytoplankton) and >200 µm (dominated by calanoid copepods). HPLC analysis revealed lowest values of α-tocopherol per L seawater in March in both size classes and highest in May for <100 µm (31.5 ng L-1) and August for >200 µm (1.3 ng L-1). No consistent seasonal pattern could be observed in α-tocopherol per unit biomass for the zooplankton. Concentrations ranged in <100 µm from 0.05 to 0.10 ng µg C-1 and in >200 µm from 0.05 to 0.11 ng µg C-1.  Partial least square regression (PLS) revealed nutrional status and species composition of the phytoplankton biomass as driving factors of α-tocopherol production in phytoplankton. Abiotic factors, as depth and temperature were only of significant influence in May. In zooplankton, the α-tocopherol concentration was negatively associated with phytoplankton biomass in May. Therefore we concluded that assimilation efficiency of zooplankton in combination with high phytoplankton biomass is the bottle-neck in tocopherol transport from phytoplankton to higher levels in the food web.

  • 64.
    Immler, Simone
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Arnqvist, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Perin Otto, Sarah
    Ploidally antagonistic selection maintains stable genetic polymorphism2012In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 66, no 1, p. 55-65Article in journal (Refereed)
    Abstract [en]

    Understanding the maintenance of genetic variation in the face of selection remains a key issue in evolutionary biology. One potential mechanism for the maintenance of genetic variation is opposing selection during the diploid and haploid stages of biphasic life cycles universal among eukaryotic sexual organisms. If haploid and diploid gene expression both occur, selection can act in each phase, potentially in opposing directions. In addition, sex-specific selection during haploid phases is likely simply because male and female gametophytes/gametes tend to have contrasting life histories. We explored the potential for the maintenance of a stable polymorphism under ploidally antagonistic as well as sex-specific selection. Furthermore, we examined the role of the chromosomal location of alleles (autosomal or sex-linked). Our analyses show that the most permissible conditions for the maintenance of polymorphism occur under negative ploidy-by-sex interactions, where stronger selection for an allele in female than male diploids is coupled with weaker selection against the allele in female than male haploids. Such ploidy-by-sex interactions also promote allele frequency differences between the sexes. With constant fitness, ploidally antagonistic selection can maintain stable polymorphisms for autosomal and X-linked genes but not for Y-linked genes. We discuss the implications of our results and outline a number of biological settings where the scenarios modeled may apply.

  • 65.
    Innocenti, Paolo
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Sexual conflict and gene expression Exploring sex-specific associations between fitness and transcriptional variation2011In: Fly, ISSN 1933-6934, Vol. 5, no 1, p. 10-13Article in journal (Refereed)
    Abstract [en]

    In recent years, the field of evolutionary biology received a fresh impulse from the increased technical and logistical availability and cost-effectiveness of genomics techniques. In particular, we have for the first time the opportunity to effectively explore and understand the genetic basis of traits variation in laboratory (and ultimately wild) populations. Traits that are most relevant in -evolutionary and ecological contexts (e.g., morphological, life-history and behavioral traits) typically show a complex genetic architecture, being affected by many loci with small effect. Such loci often interact with one another over the same trait (epistasis), affect several traits simultaneously (pleiotropy), and/or depend in their effects on the "environmental condition" in which they are expressed (genotype by environment interactions). Modern genomics offers tools, such as microarrays and high-throughput sequencing, to gather an unprecedented amount of data on gene expression and sequence variation, and can be used in the attempt to construct a genotype-phenotype map, linking genes (or gene networks), and the variation in their sequence and expression, with the natural variation of phenotypic characters.(1)

  • 66.
    Innocenti, Paolo
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Sexual Conflict and Gene Expression in Drosophila melanogaster2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Sexual conflict is broadly defined as a conflict between the evolutionary interests of the two sexes. Depending on the genetic architecture of the traits involved, it can occur at the level of male-female interactions or take the form of selection acting to change the mean of a shared trait against the sign of its genetic correlation. The aim of my thesis was to use genome-wide expression profiles in the model organism Drosophila melanogaster to provide novel insights in the study of sexual conflict.

    First, we studied the female post-mating response to partition transcriptional changes associated with reproduction from male-induced effects, which are known to be harmful to females. We found substantial changes in expression of metabolic pathways associated with the activation of reproduction, while male-specific effects were dominated by the onset of an immune response. Changes in female response under different mating strategies was studied using experimental evolution: we found that monogamous females suffered decreased fecundity and their gene expression profiles suggested an overall weaker response to mating. To identify sexually antagonistic genes, we used hemiclonal lines and associated their sex-specific fitness with genome-wide transcript abundance. We confirmed the presence of a negative covariance for fitness and identified a group of candidate genes experiencing sexually antagonistic selection. We then focused on mitochondria, which can enable the accumulation of deleterious mutations with sex-specific effects due to their maternal inheritance, and found few effects on nuclear gene expression in females but major effects in males, predominantly in male-specific tissues. Finally, we used published data to compare intraspecific and interspecific genetic variation for a set of transcripts, to test whether speciation occurs along lines of maximum genetic variance.

    In conclusion, gene expression techniques can generate useful results in the study of sexual conflict, particularly in association with phenotypic data or when integrated with published datasets.

    List of papers
    1. Immunogenic males: a genome-wide analysis of reproduction and the cost of mating in Drosophila melanogaster females
    Open this publication in new window or tab >>Immunogenic males: a genome-wide analysis of reproduction and the cost of mating in Drosophila melanogaster females
    2009 (English)In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 22, no 5, p. 964-973Article in journal (Refereed) Published
    Abstract [en]

    In Drosophila melanogaster, mating radically transforms female physiology and behaviour. Post-mating responses include an increase in the oviposition rate, a reduction in female receptivity and an activation of the immune system. The fitness consequences of mating are similarly dramatic - females must mate once in order to produce fertile eggs, but additional matings have a clear negative effect. Previously, microarrays have been used to examine gene expression of females differing in their reproductive status with the aim of identifying genes influenced by mating. However, as only virgin and single mated females were compared, transcriptional changes associated with reproduction (under natural selection) and male-induced effects (possibly under sexually antagonistic selection) cannot be disentangled. We partitioned these fundamentally different effects by instead examining the expression profiles of virgin, single mated and double mated females. We found substantial effects relating to reproduction and further effects that are only attributable to mating itself. Immune response genes dominate this male-induced effect indicating that the cost of mating may be due partly to this system's activation. We propose that both sexually antagonistic and natural selection have been important in the evolution of the innate immunity genes, thereby contributing to the sexual dimorphism and rapid evolution at these loci.

    Keywords
    BIOCONDUCTOR, cost of mating, Drosophila melanogaster, innate immunity, microarrays, post-mating female response, sexual conflict, sperm competition
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-129120 (URN)10.1111/j.1420-9101.2009.01708.x (DOI)000265252100005 ()
    Available from: 2010-08-09 Created: 2010-08-05 Last updated: 2017-12-12Bibliographically approved
    2. Genome-wide targets of selection: female response to experimental removal of sexual selection in D. melanogaster
    Open this publication in new window or tab >>Genome-wide targets of selection: female response to experimental removal of sexual selection in D. melanogaster
    (English)Manuscript (preprint) (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-156650 (URN)
    Available from: 2011-08-05 Created: 2011-08-05 Last updated: 2011-09-08
    3. The Sexually Antagonistic Genes of Drosophila melanogaster
    Open this publication in new window or tab >>The Sexually Antagonistic Genes of Drosophila melanogaster
    2010 (English)In: PLoS biology, ISSN 1544-9173, E-ISSN 1545-7885, Vol. 8, no 3, p. e1000335-Article in journal (Refereed) Published
    Abstract [en]

    When selective pressures differ between males and females, the genes experiencing these conflicting evolutionary forces are said to be sexually antagonistic. Although the phenotypic effect of these genes has been documented in both wild and laboratory populations, their identity, number, and location remains unknown. Here, by combining data on sex-specific fitness and genome-wide transcript abundance in a quantitative genetic framework, we identified a group of candidate genes experiencing sexually antagonistic selection in the adult, which correspond to 8% of Drosophila melanogaster genes. As predicted, the X chromosome is enriched for these genes, but surprisingly they represent only a small proportion of the total number of sex-biased transcripts, indicating that the latter is a poor predictor of sexual antagonism. Furthermore, the majority of genes whose expression profiles showed a significant relationship with either male or female adult fitness are also sexually antagonistic. These results provide a first insight into the genetic basis of intralocus sexual conflict and indicate that genetic variation for fitness is dominated and maintained by sexual antagonism, potentially neutralizing any indirect genetic benefits of sexual selection.

    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-136200 (URN)10.1371/journal.pbio.1000335 (DOI)000278125400013 ()
    Available from: 2010-12-10 Created: 2010-12-10 Last updated: 2017-12-11Bibliographically approved
    4. Experimental Evidence Supports a Sex-Specific Selective Sieve in Mitochondrial Genome Evolution
    Open this publication in new window or tab >>Experimental Evidence Supports a Sex-Specific Selective Sieve in Mitochondrial Genome Evolution
    2011 (English)In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 332, no 6031, p. 845-848Article in journal (Refereed) Published
    Abstract [en]

    Mitochondria are maternally transmitted; hence, their genome can only make a direct and adaptive response to selection through females, whereas males represent an evolutionary dead end. In theory, this creates a sex-specific selective sieve, enabling deleterious mutations to accumulate in mitochondrial genomes if they exert male-specific effects. We tested this hypothesis, expressing five mitochondrial variants alongside a standard nuclear genome in Drosophila melanogaster, and found striking sexual asymmetry in patterns of nuclear gene expression. Mitochondrial polymorphism had few effects on nuclear gene expression in females but major effects in males, modifying nearly 10% of transcripts. These were mostly male-biased in expression, with enrichment hotspots in the testes and accessory glands. Our results suggest an evolutionary mechanism that results in mitochondrial genomes harboring male-specific mutation loads.

    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-154276 (URN)10.1126/science.1201157 (DOI)000290529900047 ()21566193 (PubMedID)
    Available from: 2011-05-30 Created: 2011-05-30 Last updated: 2017-12-11Bibliographically approved
    5. Interspecific divergence of gene networks along lines of genetic variance in Drosophila: dimensionality, evolvability and constraints.
    Open this publication in new window or tab >>Interspecific divergence of gene networks along lines of genetic variance in Drosophila: dimensionality, evolvability and constraints.
    (English)Manuscript (preprint) (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-156651 (URN)
    Available from: 2011-08-05 Created: 2011-08-05 Last updated: 2011-09-08
  • 67.
    Innocenti, Paolo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Chenoweth, Steve
    University of Queensland, School of Biological Sciences.
    Interspecific divergence of gene networks along lines of genetic variance in Drosophila: dimensionality, evolvability and constraints.Manuscript (preprint) (Other academic)
  • 68.
    Innocenti, Paolo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Flis, Ilona
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Morrow, Edward
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Genome-wide targets of selection: female response to experimental removal of sexual selection in D. melanogasterManuscript (preprint) (Other academic)
  • 69.
    Innocenti, Paolo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Morrow, Edward H.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    A joint index for the intensity of sex-specific selection2010In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 64, no 9, p. 2775-2778Article in journal (Refereed)
    Abstract [en]

    A growing body of experimental and field data shows that selective pressures often differ between males and females. Surprisingly, to date, little attempt has been made to formalize a metric expressing the relative behavior of directional selection in the two sexes. We propose an index that describes the extent to which concordant or antagonistic selection is operating between the sexes for a given trait. This joint index could prove especially useful for the study of intralocus sexual conflict and the evolution of sexual dimorphism, providing a common scale to directly compare different traits within or among taxonomic levels, and allowing an assessment on how common sexually antagonistic selection might be in extant populations.

  • 70.
    Innocenti, Paolo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Morrow, Edward H.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    The Sexually Antagonistic Genes of Drosophila melanogaster2010In: PLoS biology, ISSN 1544-9173, E-ISSN 1545-7885, Vol. 8, no 3, p. e1000335-Article in journal (Refereed)
    Abstract [en]

    When selective pressures differ between males and females, the genes experiencing these conflicting evolutionary forces are said to be sexually antagonistic. Although the phenotypic effect of these genes has been documented in both wild and laboratory populations, their identity, number, and location remains unknown. Here, by combining data on sex-specific fitness and genome-wide transcript abundance in a quantitative genetic framework, we identified a group of candidate genes experiencing sexually antagonistic selection in the adult, which correspond to 8% of Drosophila melanogaster genes. As predicted, the X chromosome is enriched for these genes, but surprisingly they represent only a small proportion of the total number of sex-biased transcripts, indicating that the latter is a poor predictor of sexual antagonism. Furthermore, the majority of genes whose expression profiles showed a significant relationship with either male or female adult fitness are also sexually antagonistic. These results provide a first insight into the genetic basis of intralocus sexual conflict and indicate that genetic variation for fitness is dominated and maintained by sexual antagonism, potentially neutralizing any indirect genetic benefits of sexual selection.

  • 71.
    Innocenti, Paolo
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Morrow, Edward H.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Dowling, Damian K.
    Experimental Evidence Supports a Sex-Specific Selective Sieve in Mitochondrial Genome Evolution2011In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 332, no 6031, p. 845-848Article in journal (Refereed)
    Abstract [en]

    Mitochondria are maternally transmitted; hence, their genome can only make a direct and adaptive response to selection through females, whereas males represent an evolutionary dead end. In theory, this creates a sex-specific selective sieve, enabling deleterious mutations to accumulate in mitochondrial genomes if they exert male-specific effects. We tested this hypothesis, expressing five mitochondrial variants alongside a standard nuclear genome in Drosophila melanogaster, and found striking sexual asymmetry in patterns of nuclear gene expression. Mitochondrial polymorphism had few effects on nuclear gene expression in females but major effects in males, modifying nearly 10% of transcripts. These were mostly male-biased in expression, with enrichment hotspots in the testes and accessory glands. Our results suggest an evolutionary mechanism that results in mitochondrial genomes harboring male-specific mutation loads.

  • 72.
    Jaenson, Thomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Systematic Biology.
    Jaenson, David GE
    Eisen, Lars
    Petersson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Lindgren, Elisabet
    Karolinska institutet.
    Changes in the geographical distribution and abundance of the tick Ixodes ricinus during the past 30 years in Sweden2012In: Parasites & Vectors, ISSN 1756-3305, Vol. 5, no 8Article in journal (Refereed)
    Abstract [en]

    Background: Ixodes ricinus is the main vector in Europe of human-pathogenic Lyme borreliosis (LB) spirochaetes, the tick-borne encephalitis virus (TBEV) and other pathogens of humans and domesticated mammals. The results of a previous 1994 questionnaire, directed at people living in Central and North Sweden (Svealand and Norrland) and aiming to gather information about tick exposure for humans and domestic animals, suggested that Ixodes ricinus ticks had become more widespread in Central Sweden and the southern part of North Sweden from the early 1980s to the early 1990s. To investigate whether the expansion of the tick's northern geographical range and the increasing abundance of ticks in Sweden were still occurring, in 2009 we performed a follow-up survey 16 years after the initial study.

    Methods: A questionnaire similar to the one used in the 1994 study was published in Swedish magazines aimed at dog owners, home owners, and hunters. The questionnaire was published together with a popular science article about the tick's biology and role as a pathogen vector in Sweden. The magazines were selected to get information from people familiar with ticks and who spend time in areas where ticks might be present.

    Results: Analyses of data from both surveys revealed that during the near 30-year period from the early 1980s to 2008, I. ricinus has expanded its distribution range northwards. In the early 1990s ticks were found in new areas along the northern coastline of the Baltic Sea, while in the 2009 study, ticks were reported for the first time from many locations in North Sweden. This included locations as far north as 66 degrees N and places in the interior part of North Sweden. During this 16-year period the tick's range in Sweden was estimated to have increased by 9.9%. Most of the range expansion occurred in North Sweden (north of 60 degrees N) where the tick's coverage area doubled from 12.5% in the early 1990s to 26.8% in 2008. Moreover, according to the respondents, the abundance of ticks had increased markedly in LB- and TBE-endemic areas in South (Gotaland) and Central Sweden.

    Conclusions: The results suggest that I. ricinus has expanded its range in North Sweden and has become distinctly more abundant in Central and South Sweden during the last three decades. However, in the northern mountain region I. ricinus is still absent. The increased abundance of the tick can be explained by two main factors: First, the high availability of large numbers of important tick maintenance hosts, i.e., cervids, particularly roe deer (Capreolus capreolus) during the last three decades. Second, a warmer climate with milder winters and a prolonged growing season that permits greater survival and proliferation over a larger geographical area of both the tick itself and deer. High reproductive potential of roe deer, high tick infestation rate and the tendency of roe deer to disperse great distances may explain the range expansion of I. ricinus and particularly the appearance of new TBEV foci far away from old TBEV-endemic localities. The geographical presence of LB in Sweden corresponds to the distribution of I. ricinus. Thus, LB is now an emerging disease risk in many parts of North Sweden. Unless countermeasures are undertaken to keep the deer populations, particularly C. capreolus and Dama dama, at the relatively low levels that prevailed before the late 1970s - especially in and around urban areas where human population density is high by e. g. reduced hunting of red fox (Vulpes vulpes) and lynx (Lynx lynx), the incidences of human LB and TBE are expected to continue to be high or even to increase in Sweden in coming decades.

  • 73.
    Jandér, K. Charlotte
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Herre, Edward Allen
    Host sanctions and pollinator cheating in the fig tree-fig wasp mutualism2010In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 277, no 1687, p. 1481-1488Article in journal (Refereed)
    Abstract [en]

    Theory predicts that mutualisms should be vulnerable to invasion by cheaters, yet mutualistic interactions are both ancient and diverse. What prevents one partner from reaping the benefits of the interaction without paying the costs? Using field experiments and observations, we examined factors affecting mutualism stability in six fig tree-fig wasp species pairs. We experimentally compared the fitness of wasps that did or did not perform their most basic mutualistic service, pollination. We found host sanctions that reduced the fitness of non-pollinating wasps in all derived, actively pollinated fig species (where wasps expend time and energy pollinating), but not in the basal, passively pollinated fig species (where wasps do not). We further screened natural populations of pollinators for wasp individuals that did not carry pollen ('cheaters'). Pollen-free wasps occurred only in actively pollinating wasp species, and their prevalence was negatively correlated with the sanction strength of their host species. Combined with previous studies, our findings suggest that (i) mutualisms can show coevolutionary dynamics analogous to those of 'arms races' in overtly antagonistic interactions; (ii) sanctions are critical for long-term mutualism stability when providing benefits to a host is costly, and (iii) there are general principles that help maintain cooperation both within and among species.

  • 74. Jones, Theresa M.
    et al.
    Arnqvist, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    McNamara, Kathryn B.
    Elgar, Mark A.
    Size-assortative pairing across three developmental stages in the Zeus bug, Phoreticovelia disparata2012In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 66, no 7, p. 995-1003Article in journal (Refereed)
    Abstract [en]

    The mechanisms underlying size-assortative pairing have received considerable attention. Typically, pairing is assumed to occur at, or just prior to, the adult phase of the life cycle. However, in many invertebrates, males commence associations with juvenile females who are more than a single moult away from sexual maturity. These species are ideal to explore the importance of reproductive and survival benefits as mechanisms driving size-assortative pairing. In the Zeus bug, Phoreticovelia disparata, adult males are found riding on juvenile (fourth and fifth instar) and adult females-a behaviour that is costly for females but has survival benefits for males. Using a combination of field collections and laboratory manipulations, we show that pairing is size-assortative both within and between female age classes and that riding males are smaller than non-riding males. In a series of mating trials, we revealed that males attempt to ride any female but that their riding success is dependent on female age. We also provide the first direct evidence of female resistance to male riding attempts in P. disparata. We propose that size-assortative pairing arises through adaptations that have evolved to minimise the potential costs of sexual conflict. We suggest that the selective pressure on males to maximise survival benefits is sufficiently high that it outweighs the reproductive benefits of discriminating against fourth instar females. Finally, given that female resistance is under direct selection in juvenile females, it is likely to be the main form of selective pressure for adult females.

  • 75.
    Kazancioglu, Erem
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Alonzo, Suzanne H.
    The evolution of optimal female mating rate changes the coevolutionary dynamics of female resistance and male persistence2012In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, E-ISSN 1471-2970, Vol. 367, no 1600, p. 2339-2347Article in journal (Refereed)
    Abstract [en]

    Mating decisions usually involve conflict of interests between sexes. Accordingly, males benefit from increased number of matings, whereas costs of mating favour a lower mating rate for females. The resulting sexual conflict underlies the coevolution of male traits that affect male mating success ('persistence') and female traits that affect female mating patterns ('resistance'). Theoretical studies on the coevolutionary dynamics of male persistence and female resistance assumed that costs of mating and, consequently, the optimal female mating rate are evolutionarily constant. Costs of mating, however, are often caused by male 'persistence' traits that determine mating success. Here, we present a model where the magnitude of costs of mating depend on, and evolve with, male persistence. We find that allowing costs of mating to depend on male persistence results in qualitatively different coevolutionary dynamics. Specifically, we find that male traits such as penis spikes that harm females are not predicted to exhibit runaway selection with female resistance, in contrast to previous theory that predicts indefinite escalation. We argue that it is essential to determine when and to what extent costs of mating are caused by male persistence in order to understand and accurately predict coevolutionary dynamics of traits involved in mating decisions.

  • 76.
    Kazancıoğlu, Erem
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Alonzo, S. H.
    Classic predictions about sex change do not hold under all types of size advantage2010In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 23, no 11, p. 2432-2441Article in journal (Refereed)
    Abstract [en]

    Theory predicts that the 'size advantage' (rate of increase in male and female fitness with age or size) determines the direction and the timing of sex change in sequential hermaphrodites. Whereas the size advantage is generated by the mating system and would be expected to vary within and between species, the shape or form of the size advantage has rarely been estimated directly. Here, we ask whether theoretical predictions about the timing of sex change hold under different types of size advantage. We model two biological scenarios representing different processes generating the size advantage and find that different types of size advantage can produce patterns that qualitatively differ from classic predictions. Our results demonstrate that a good understanding of sequentially hermaphroditic mating systems, and specifically, a direct assessment of the processes underlying the size advantage is crucial to reliably predict and explain within-species patterns of the timing of sex change.

  • 77.
    Kazancıoğlu, Erem
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Klug, Hope
    Alonzo, Suzanne H.
    The evolution of social interactions changes predictions about interacting phenotypes2012In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 66, no 7, p. 2056-2064Article in journal (Refereed)
    Abstract [en]

    In many traits involved in social interactions, such as courtship and aggression, the phenotype is an outcome of interactions between individuals. Such traits whose expression in an individual is partly determined by the phenotype of its social partner are called interacting phenotypes. Quantitative genetic models suggested that interacting phenotypes can evolve much faster than nonsocial traits. Current models, however, consider the interaction between phenotypes of social partners as a fixed phenotypic response rule, represented by an interaction coefficient (?). Here, we extend existing theoretical models and incorporate the interaction coefficient as a trait that can evolve. We find that the evolution of the interaction coefficient can change qualitatively the predictions about the rate and direction of evolution of interacting phenotypes. We argue that it is crucial to determine whether and how the phenotypic response of an individual to its social partner can evolve to make accurate predictions about the evolution of traits involved in social interactions.

  • 78.
    Kolm, Niclas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Amcoff, Mirjam
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Mann, Richard P.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Mathematics, Analysis and Applied Mathematics.
    Arnqvist, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Diversification of a Food-Mimicking Male Ornament via Sensory Drive2012In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 22, no 15, p. 1440-1443Article in journal (Refereed)
    Abstract [en]

    The evolutionary divergence of sexual signals is often important during the formation of new animal species, but our understanding of the origin of signal diversity is limited [1, 2]. Sensory drive, the optimization of communication signal efficiency through matching to the local environment, has been highlighted as a potential promoter of diversification and speciation [3]. The swordtail characin (Corynopoma riisei) is a tropical fish in which males display a flag-like ornament that elicits female foraging behavior during courtship. We show that the shape of the male ornament covaries with female diet across natural populations. More specifically, natural populations in which the female diet is more dominated by ants exhibit male ornaments more similar to the shape of an ant. Feeding experiments confirm that females habituated to a diet of ants prefer to bite at male ornaments from populations with a diet more dominated by ants. Our results show that the male ornament functions as a "fishing lure" that is diversifying in shape to match local variation in female search images employed during foraging. This direct link between variation in female feeding ecology and the evolutionary diversification of male sexual ornaments suggests that sensory drive may be a common engine of signal divergence.

  • 79.
    Kolm, Niclas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Arnqvist, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Environmental correlates of diet in the swordtail characin (Corynopoma riisei, gill)2011In: Environmental Biology of Fishes, ISSN 0378-1909, E-ISSN 1573-5133, Vol. 92, no 2, p. 159-166Article in journal (Refereed)
    Abstract [en]

    In the sexually dimorphic swordtail characin (Corynopoma riisei, Gill), males are equipped with an opercular flag-ornament that has been suggested to function as a food-mimic since females bite at the ornament during courtship. However, virtually nothing is known about the diet in wild populations of this species. In this study, we first investigated composition of and variation in the diet of C. riisei across 18 different populations in Trinidad, using gut content analyses. We then related variation in gut content to habitat features of populations to investigate the potential link between environmental conditions and prey utilization. Our results showed that the dominating food type in the gut was various terrestrial invertebrates, both adults and larvae, but we also document substantial variation in prey types across populations. Furthermore, a canonical correlation analysis revealed a relationship between environmental characteristics and diet: populations from wider and more rapidly flowing streams with more canopy cover tended to have a diet based more on ants and mosquitoes while populations from narrow and slow flowing streams with little canopy cover tended to have a diet based more on springtails, mites and mayfly larvae. Our results add novel information on the ecology of this interesting fish and suggest the possibility of local adaptation reflecting differences in prey availability across natural populations.

  • 80. Kolm, Niclas
    et al.
    Berglund, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Wild populations of a reef fish suffer from the “nondestructive” aquarium trade fishery2003In: Conservation Biology, ISSN 0888-8892, E-ISSN 1523-1739, Vol. 17, p. 910-914Article in journal (Refereed)
  • 81.
    Kotrschal, Alexander
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Fischer, Barbara
    Taborsky, Barbara
    A Noninvasive Method to Determine Fat Content in Small Fish Based on Swim Bladder Size Estimation2011In: Journal of Experimental Zoology. Part A: Ecological Genetics and Physiology, ISSN 1932-5223, E-ISSN 1932-5231, Vol. 315A, no 7, p. 408-415Article in journal (Refereed)
    Abstract [en]

    The presence of fat stores in fish is widely used as a correlate of fish health and fitness. Techniques to measure fat content with some accuracy are available for medium-sized and large fish, but apart from morphometric indices, a noninvasive method to determine fat content in small fish has hitherto been lacking. In this study, we introduce a novel method to measure the fat content in live fish that can be applied also to small fish of less than 0.5 g of body mass. This approach relies on a precise measurement of the swim bladder volume, from which fat content can subsequently be deduced. As fat is positively buoyant, fish with larger fat stores require a smaller swim bladder to attain neutral buoyancy. To determine swim bladder volume, we developed a measuring device, which makes use of the differential compressibility of air and water. A fish is placed in a pressure-tight chamber to which a standardized amount of water is added. The resulting change in pressure Delta p is inversely proportional to the volume of the swim bladder. Using juveniles and adults of Simochromis pleurospilus (Nelissen, '78; Pisces: Tropheini) a small cichlid fish, we show that Delta p is tightly related to structural size, mass, and body condition. Most importantly, this approach allows to predict the visceral fat content of small fish more precisely than the six most commonly used morphometric body indices.

  • 82.
    Kotrschal, Alexander
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Heckel, Gerald
    Bonfils, Danielle
    Taborsky, Barbara
    Life-stage specific environments in a cichlid fish: implications for inducible maternal effects2012In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 26, no 1, p. 123-137Article in journal (Refereed)
    Abstract [en]

    Through environmentally induced maternal effects females may fine-tune their offspring's phenotype to the conditions offspring will encounter after birth. If juvenile and adult ecologies differ, the conditions mothers experienced as juveniles may better predict their offspring's environment than the adult females' conditions. Maternal effects induced by the environment experienced by females during their early ontogeny should evolve when three ecological conditions are met: (1) Adult ecology does not predict the postnatal environmental conditions of offspring; (2) Environmental conditions for juveniles are correlated across successive generations; and (3) Juveniles occasionally settle in conditions that differ from the juvenile habitat of their mothers. By combining size-structured population counts, ecological surveys and a genetic analysis of population structure we provide evidence that all three conditions hold for Simochromis pleurospilus, a cichlid fish in which mothers adjust offspring quality to their own juvenile ecology. In particular we show (1) that the spatial niches and the habitat quality differ between juveniles and adults, and we provide genetic evidence (2) that usually fish of successive generations grow up in similar habitats, and (3) that occasional dispersal in populations with a different habitat quality is likely to occur. As adults of many species cannot predict their offspring's environment from ambient cues, life-stage specific maternal effects are likely to be common in animals. It will therefore be necessary to incorporate parental ontogeny in the study of parental effects when juveniles and adults inhabit different environments.

  • 83.
    Kotrschal, Alexander
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Rasanen, Katja
    Kristjansson, Bjarni K.
    Senn, Mike
    Kolm, Niclas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Extreme Sexual Brain Size Dimorphism in Sticklebacks: A Consequence of the Cognitive Challenges of Sex and Parenting?2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 1, p. e30055-Article in journal (Refereed)
    Abstract [en]

    Selection pressures that act differently on males and females produce numerous differences between the sexes in morphology and behaviour. However, apart from the controversial report that males have slightly heavier brains than females in humans, evidence for substantial sexual dimorphism in brain size is scarce. This apparent sexual uniformity is surprising given that sexually distinct selection pressures are ubiquitous and that brains are one of the most plastic vertebrate organs. Here we demonstrate the highest level of sexual brain size dimorphism ever reported in any vertebrate: male three-spined stickleback of two morphs in an Icelandic lake have 23% heavier brains than females. We suggest that this dramatic sexual size dimorphism is generated by the many cognitively demanding challenges that males are faced in this species, such as an elaborate courtship display, the construction of an ornate nest and a male-only parental care system. However, we consider also alternative explanations for smaller brains in females, such as life-history trade-offs. Our demonstration of unprecedented levels of sexual dimorphism in brain size in the three-spined stickleback implies that behavioural and life-history differences among the sexes can have strong effects also on neural development and proposes new fields of research for understanding brain evolution.

  • 84.
    Kotrschal, Alexander
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Rogell, Björn
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Maklakov, Alexei A.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Kolm, Nichlas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Sex-specific plasticity in brain morphology depends on social environment of the guppy, Poecilia reticulata2012In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 66, no 11, p. 1485-1492Article in journal (Refereed)
    Abstract [en]

    The vertebrate brain is a remarkably plastic organ, which responds quickly to environmental changes. However, to date, studies investigating plasticity in brain morphology have focused mostly on the physical properties of the surrounding environment, and little is known about brain plasticity in response to the social environment. Moreover, sex differences in brain plasticity remain virtually unexplored. Here, we tested how the social environment influenced brain morphology in adult males and females using experimental manipulation of the sex composition of social pairs (same sex vs. mixed sex) in the guppy (Poecilia reticulata). We detected substantial sex-specific plasticity in both the overall brain size (controlling for body size) and separate brain structures. The brain size was larger in males that interacted with females, and female optic tectum was larger in female-only groups. Overall, females had larger olfactory bulbs and cerebellum in comparison to males. While net sexual dimorphism in the brain structure can be explained in light of the known differences in boldness and foraging behaviour between the sexes, our results also support that cognitive demands associated with courtship behaviour can lead to plastic changes in the brain size. Our findings demonstrate that not only social environment can generate rapid, plastic responses in the vertebrate brain but also that such responses can depend strongly on sex.

  • 85.
    Kotrschal, Alexander
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Sundström, L. Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Brelin, D.
    Devlin, R. H.
    Kolm, Niclas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Inside the heads of David and Goliath: environmental effects on brain morphology among wild and growth-enhanced coho salmon Oncorhynchus kisutch2012In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 81, no 3, p. 987-1002Article in journal (Refereed)
    Abstract [en]

    Transgenic and wild-type individual coho salmon Oncorhynchus kisutch were reared in hatchery and near-natural stream conditions and their brain and structure sizes were determined. Animals reared in the hatchery grew larger and developed larger brains, both absolutely and when controlling for body size. In both environments, transgenics developed relatively smaller brains than wild types. Further, the volume of the optic tectum of both genotypes was larger in the hatchery animals and the cerebellum of transgenics was smaller when reared in near-natural streams. Finally, wild types developed a markedly smaller telencephalon under hatchery conditions. It is concluded that, apart from the environment, genetic factors that modulate somatic growth rate also have a strong influence on brain size and structure.

  • 86.
    Kulma, Katarzyna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Avian malaria, life-history trade-offs and interspecific competition in Ficedula flycatchers2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis investigates the impact of avian malaria (Haemosporidia) parasites on the outcome of interspecific competition between two closely related bird species, pied (Ficedula hypoleuca) and collared (F. albicollis) flycatchers. I further investigated how variation in timing of breeding, life history strategies and immune competence genes (MHC genes) modulate the fitness effects of malaria parasites in one of the two species i.e. collared flycatchers. Collared flycatchers colonized the Baltic island Öland in the late 1950-ties and has since then been expanding their breeding range while competitively excluding pied flycatchers from the favourable habitats (deciduous forests). I investigated the underlying mechanisms behind this exclusion by combining detailed long-term breeding data with modern molecular genetic techniques identifying both the presence/absence and lineage specificity of haemosporidian blood parasites. I found that the rapid decline of pied flycatchers can be explained by the combined effects of competition over nestling sites, hybridization and haemosporidian infections. Haemosporidian infections have a negative impact on survival of pied flycatcher females but no detectable effect on collared flycatchers’ longevity or reproductive success. This may be due to the fact that collared flycatchers carry (and are potentially exposed to) a higher diversity of parasites than pied flycatchers, which in turn may select for a higher diversity of MHC genes and hence a better overall protection from the negative impact of parasites. Indeed, functional MHC diversity correlates negatively with malaria prevalence among collared flycatchers from Gotland. Moreover, I found that both, malaria infection intensity and immunoglobulin level influences how infected collared flycatchers respond to increased nestling food-demands. The latter results mean that there is variation in allocation strategies (i.e. in resource allocation between reproductive effort and immune competence) within the collared flycatcher population. Hence, this population has the ability to respond to novel selection pressures in terms of optimal allocation of resources into immune functions. In summary, my results show that local parasites may facilitate the expansion of a new colonizer. This is important in the context of global climate change that will probably increase the colonization rate of southern species and lead to novel host-parasite interactions.

    List of papers
    1. Combined effects of interspecific competition and hybridization impede local coexistence of Ficedula flycatchers
    Open this publication in new window or tab >>Combined effects of interspecific competition and hybridization impede local coexistence of Ficedula flycatchers
    Show others...
    2012 (English)In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 26, no 4, p. 927-942Article in journal (Refereed) Published
    Abstract [en]

    At secondary contact closely related species may both compete over similar resources and/or hybridize. Simulation models suggest that hybridization increases the risk of extinction beyond the risk resulting from interspecific competition alone, but such combined effects are rarely studied empirically. Here, we use detailed records on pairing patterns, breeding success, local recruitment and immigration collected during 8 years (2002-2009) to investigate the underlying mechanism of the rapid displacement of pied flycatchers by collared flycatchers on the Swedish island of A-land. We found no differences in average reproductive success or reproductive lifespan between the two species. However, we show that young male pied flycatchers failed to establish new territories as the density of male collared flycatchers increased. In addition, as the relative frequency of collared flycatchers increased, the risk of hybridization dramatically increased for female pied flycatchers, which speeds up the exclusion process since there is a high fitness cost associated with hybridization between the two species. In a nearby control area, within the same island, where pied flycatchers breed in the absence of collared flycatchers, no decline in the number of breeding pairs was observed during the same period of time. Our results demonstrate the crucial importance of studying the combined effects of various types of heterospecific interactions to understand and predict the ecological and evolutionary implications of secondary contact between congeneric species. These findings are particularly interesting in the light of recent climate change since the expected range shifts of many taxa will increase competitive and sexual interactions between previously separated species.

    Keywords
    Competition, Coexistence, Extinction, Hybridization, Reproductive interference
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-157138 (URN)10.1007/s10682-011-9536-0 (DOI)000305218900011 ()
    Available from: 2011-08-17 Created: 2011-08-17 Last updated: 2017-12-08Bibliographically approved
    2. Malaria infections reinforce competitive asymmetry between two Ficedula flycatchers in a recent contact zone
    Open this publication in new window or tab >>Malaria infections reinforce competitive asymmetry between two Ficedula flycatchers in a recent contact zone
    2013 (English)In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 22, no 17, p. 4591-4601Article in journal (Refereed) Published
    Abstract [en]

    Parasites may influence the outcome of interspecific competition between closely-related host species through lower parasite virulence in the host with which they share the longer evolutionary history. We tested this idea by comparing the prevalence of avian malaria (Haemosporidia) lineages and their association with survival in pied and collared flycatchers (Ficedula hypoleuca & F. albicollis) breeding in a recent contact zone on the Swedish island of Öland. A nested PCR protocol amplifying haemosporidian fragments of mtDNA was used to screen the presence of malaria lineages in 1048 blood samples collected during 6 years. Competitively inferior pied flycatchers had a higher prevalence of blood parasites, including the lineages that were shared between the two flycatcher species. Multistate mark-recapture models revealed a lower survival of infected versus uninfected female pied flycatchers, while no such effects were detected in male pied flycatchers or in collared flycatchers of either sex. Our results show that a comparatively new host, the collared flycatcher, appears to be less susceptible to a local northern European malarial lineage where the collared flycatchers have recently expanded their distribution. Pied flycatchers experience strong reproductive interference from collared flycatchers, and the additional impact of species-specific blood parasite effects adds to this competitive exclusion. These results support the idea that parasites can strongly influence the outcome of interspecific competition between closely-related host species, but that the invading species need not necessarily be more susceptible to local parasites.

    Keywords
    annual survival, apparent competition, Haemoproteus, Plasmodium
    National Category
    Ecology
    Identifiers
    urn:nbn:se:uu:diva-204308 (URN)10.1111/mec.12409 (DOI)000323506400018 ()23980765 (PubMedID)
    Available from: 2013-07-29 Created: 2013-07-29 Last updated: 2017-12-06Bibliographically approved
    3. Malaria-infected female collared flycatchers (Ficedula albicollis) do not pay the cost of late breeding
    Open this publication in new window or tab >>Malaria-infected female collared flycatchers (Ficedula albicollis) do not pay the cost of late breeding
    2014 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 1, p. e85822-Article in journal (Refereed) Published
    Abstract [en]

    Life-history theory predicts that the trade-off between parasite defense and other costly traits such as reproduction may be most evident when resources are scarce. The strength of selection that parasites inflict on their host may therefore vary across environmental conditions. Collared flycatchers (Ficedula albicollis) breeding on the Swedish island Oland experience a seasonal decline in their preferred food resource, which opens the possibility to test the strength of life-history trade-offs across environmental conditions. We used nested-PCR and quantitative-PCR protocols to investigate the association of Haemosporidia infection with reproductive performance of collared flycatcher females in relation to a seasonal change in the external environment. We show that despite no difference in mean onset of breeding, infected females produced relatively more of their fledglings late in the season. This pattern was also upheld when considering only the most common malaria lineage (hPHSIB1), however there was no apparent link between the reproductive output and the intensity of infection. Infected females produced heavier-than-average fledglings with higher-than-expected recruitment success late in the season. This reversal of the typical seasonal trend in reproductive output compensated them for lower fledging and recruitment rates compared to uninfected birds earlier in the season. Thus, despite different seasonal patterns of reproductive performance the overall number of recruits was the same for infected versus uninfected birds. A possible explanation for our results is that infected females breed in a different microhabitat where food availability is higher late in the season but also is the risk of infection. Thus, our results suggest that another trade-off than the one we aimed to test is more important for explaining variation in reproductive performance in this natural population: female flycatchers appear to face a trade-off between the risk of infection and reproductive success late in the season.

    Keywords
    avian malaria, blood parasites, Haemoproteus, Haemosporidia, reproductive cost, reproductive success, trade-off
    National Category
    Ecology
    Identifiers
    urn:nbn:se:uu:diva-204310 (URN)10.1371/journal.pone.0085822 (DOI)000330288000027 ()
    Available from: 2013-07-29 Created: 2013-07-29 Last updated: 2017-12-06Bibliographically approved
    4. Immunoglobulin level and infection intensity influence how malaria-infected collared flycatchers respond to brood size manipulation
    Open this publication in new window or tab >>Immunoglobulin level and infection intensity influence how malaria-infected collared flycatchers respond to brood size manipulation
    Show others...
    (English)Article in journal (Refereed) Submitted
    Abstract [en]

    1.The existence of a trade-off between investment in reproduction and immune function is well-established in many species. However, variation in the underlying physiological allocation strategies, which is what selection operates on, remains largely unexplored.

    2.We investigated how haemosporidian infection influenced stress hormone level and ability to increase parental effort in female collared flycatchers (Ficedula albicollis). We especially focused on how estimates of investment in humoral immune response and level of parasitemia influenced subsequent parental investment (i.e. offspring provisioning and offspring mass).

    3.To achieve these goals, we combined a brood size manipulation experiment with nested- and quantitative PCR methods to establish infection status and intensity. In addition, we quantified immunoglobulin Y (IgY) and stress protein levels.

    4. Malaria-infected females reared enlarged broods with lower mass but there was large variation in their response to the experiment. Only infected females with low IgY levels decreased their relative provisioning rate and there was a positive relationship between the intensity of infection and total brood mass.

    5. Our study implies that malaria-infected flycatchers experience a trade-off between keeping their infection at bay (i.e. low level of parasitemia) and responding to increased offspring demands (i.e. high offspring mass in enlarged broods). However, relatively immunocompetent individuals (i.e. individuals with high IgY levels) did not compromise their parental care suggesting that the main cost of raising the immune response does not lay in antibody production.

    Keywords
    Avian malaria, Haemoproteus, life-history strategy, parental effort, Plasmodium
    National Category
    Ecology
    Identifiers
    urn:nbn:se:uu:diva-204309 (URN)
    Available from: 2013-07-29 Created: 2013-07-29 Last updated: 2015-11-24Bibliographically approved
    5. MHC diversity, malaria and lifetime reproductive success in collared flycatchers
    Open this publication in new window or tab >>MHC diversity, malaria and lifetime reproductive success in collared flycatchers
    Show others...
    2012 (English)In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 21, no 10, p. 2469-2479Article in journal (Refereed) Published
    Abstract [en]

    Major histocompatibility complex (MHC) genes encode proteins involved in the recognition of parasite-derived antigens. Their extreme polymorphism is presumed to be driven by co-evolution with parasites. Hostparasite co-evolution was also hypothesized to optimize within-individual MHC diversity at the intermediate level. Here, we use unique data on lifetime reproductive success (LRS) of female collared flycatchers to test whether LRS is associated with within-individual MHC class II diversity. We also examined the association between MHC and infection with avian malaria. Using 454 sequencing, we found that individual flycatchers carry between 3 and 23 functional MHC class II B alleles. Predictions of the optimality hypothesis were not confirmed by our data as the prevalence of blood parasites decreased with functional MHC diversity. Furthermore, we did not find evidence for an association between MHC diversity and LRS.

    Keywords
    fitness, genetic variation, immune response, major histocompatibility complex, optimality hypothesis, parasites, selection
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-174920 (URN)10.1111/j.1365-294X.2012.05547.x (DOI)000303388300014 ()
    Available from: 2012-05-30 Created: 2012-05-30 Last updated: 2017-12-07Bibliographically approved
  • 87.
    Kulma, Katarzyna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Butterfield, Eileen
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Strand, Tanja
    Swedish Institute for Communicable Disease Control, Stockholm, Sweden.
    Lundkvist, Åke
    Swedish Institute for Communicable Disease Control, Stockholm, Sweden.
    Qvarnström, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Immunoglobulin level and infection intensity influence how malaria-infected collared flycatchers respond to brood size manipulationArticle in journal (Refereed)
    Abstract [en]

    1.The existence of a trade-off between investment in reproduction and immune function is well-established in many species. However, variation in the underlying physiological allocation strategies, which is what selection operates on, remains largely unexplored.

    2.We investigated how haemosporidian infection influenced stress hormone level and ability to increase parental effort in female collared flycatchers (Ficedula albicollis). We especially focused on how estimates of investment in humoral immune response and level of parasitemia influenced subsequent parental investment (i.e. offspring provisioning and offspring mass).

    3.To achieve these goals, we combined a brood size manipulation experiment with nested- and quantitative PCR methods to establish infection status and intensity. In addition, we quantified immunoglobulin Y (IgY) and stress protein levels.

    4. Malaria-infected females reared enlarged broods with lower mass but there was large variation in their response to the experiment. Only infected females with low IgY levels decreased their relative provisioning rate and there was a positive relationship between the intensity of infection and total brood mass.

    5. Our study implies that malaria-infected flycatchers experience a trade-off between keeping their infection at bay (i.e. low level of parasitemia) and responding to increased offspring demands (i.e. high offspring mass in enlarged broods). However, relatively immunocompetent individuals (i.e. individuals with high IgY levels) did not compromise their parental care suggesting that the main cost of raising the immune response does not lay in antibody production.

  • 88.
    Kulma, Katarzyna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Low, Matthew
    Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Bensch, Staffan
    Lund University, Lund, Sweden.
    Qvarnström, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Malaria infections reinforce competitive asymmetry between two Ficedula flycatchers in a recent contact zone2013In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 22, no 17, p. 4591-4601Article in journal (Refereed)
    Abstract [en]

    Parasites may influence the outcome of interspecific competition between closely-related host species through lower parasite virulence in the host with which they share the longer evolutionary history. We tested this idea by comparing the prevalence of avian malaria (Haemosporidia) lineages and their association with survival in pied and collared flycatchers (Ficedula hypoleuca & F. albicollis) breeding in a recent contact zone on the Swedish island of Öland. A nested PCR protocol amplifying haemosporidian fragments of mtDNA was used to screen the presence of malaria lineages in 1048 blood samples collected during 6 years. Competitively inferior pied flycatchers had a higher prevalence of blood parasites, including the lineages that were shared between the two flycatcher species. Multistate mark-recapture models revealed a lower survival of infected versus uninfected female pied flycatchers, while no such effects were detected in male pied flycatchers or in collared flycatchers of either sex. Our results show that a comparatively new host, the collared flycatcher, appears to be less susceptible to a local northern European malarial lineage where the collared flycatchers have recently expanded their distribution. Pied flycatchers experience strong reproductive interference from collared flycatchers, and the additional impact of species-specific blood parasite effects adds to this competitive exclusion. These results support the idea that parasites can strongly influence the outcome of interspecific competition between closely-related host species, but that the invading species need not necessarily be more susceptible to local parasites.

  • 89.
    Kulma, Katarzyna
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Low, Matthew
    Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Bensch, Staffan
    Lund University, Lund, Sweden.
    Qvarnström, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Malaria-infected female collared flycatchers (Ficedula albicollis) do not pay the cost of late breeding2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 1, p. e85822-Article in journal (Refereed)
    Abstract [en]

    Life-history theory predicts that the trade-off between parasite defense and other costly traits such as reproduction may be most evident when resources are scarce. The strength of selection that parasites inflict on their host may therefore vary across environmental conditions. Collared flycatchers (Ficedula albicollis) breeding on the Swedish island Oland experience a seasonal decline in their preferred food resource, which opens the possibility to test the strength of life-history trade-offs across environmental conditions. We used nested-PCR and quantitative-PCR protocols to investigate the association of Haemosporidia infection with reproductive performance of collared flycatcher females in relation to a seasonal change in the external environment. We show that despite no difference in mean onset of breeding, infected females produced relatively more of their fledglings late in the season. This pattern was also upheld when considering only the most common malaria lineage (hPHSIB1), however there was no apparent link between the reproductive output and the intensity of infection. Infected females produced heavier-than-average fledglings with higher-than-expected recruitment success late in the season. This reversal of the typical seasonal trend in reproductive output compensated them for lower fledging and recruitment rates compared to uninfected birds earlier in the season. Thus, despite different seasonal patterns of reproductive performance the overall number of recruits was the same for infected versus uninfected birds. A possible explanation for our results is that infected females breed in a different microhabitat where food availability is higher late in the season but also is the risk of infection. Thus, our results suggest that another trade-off than the one we aimed to test is more important for explaining variation in reproductive performance in this natural population: female flycatchers appear to face a trade-off between the risk of infection and reproductive success late in the season.

  • 90. Kuparinen, Anna
    et al.
    Björklund, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Theory put into practice: an R implementation of the infinite-dimensional model2011In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 222, no 12, p. 2027-2030Article in journal (Refereed)
    Abstract [en]

    The infinite dimensional model (IDM) is an approach that has been developed for the analyses of phenotypic variation in function valued traits such as growth trajectories and continuous reaction norms. This model is particularly suited for the analysis of the potential and the constraints for growth to evolve under selection on body size. Despite of its applicability to a broad range of study systems IDM has only been applied in a handful of studies, as it is mathematically demanding for scientists not familiar with quantitative genetics methods. Here, we present a user-friendly R implementation of IDM, demonstrate its performance with growth data on nine-spined stickleback (Pungitius pungitius). In addition to rearing experiments, individual based size-at-age trajectories are often measured in wild in mark-recapture studies or estimated retrospectively from scales or bones. Therefore, our R implementation of IDM should be applicable to many studies conducted in wild and in a lab, and be useful by making the methodologically challenging IDM approach more easily accessible also in the fields where quantitative genetics methods are less standardly used.

  • 91. Kvarnemo, C.
    et al.
    Mobley, K. B.
    Partridge, C.
    Jones, A. G.
    Ahnesjö, Ingrid
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Evidence of paternal nutrient provisioning to embryos in broad-nosed pipefish Syngnathus typhle2011In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 78, no 6, p. 1725-1737Article in journal (Refereed)
    Abstract [en]

    In two experiments, radioactively labelled nutrients (either H-3-labelled amino-acid mixture or C-14-labelled glucose) were tube-fed to brooding male Syngnathus typhle. Both nutrients were taken up by the males and radioactivity generally increased in the brood pouch tissue with time. Furthermore, a low but significant increase of H-3-labelled amino acids in embryos was found over the experimental interval (48 h), whereas in the C-14-glucose experiment the radioactivity was taken up by the embryos but did not increase over the experimental time (320 min). Uptake of radioisotopes per embryo did not differ with embryo size. A higher uptake mg(-1) tissue of both H-3-labelled amino acids and C-14-labelled glucose was found in smaller embryos, possibly due to a higher relative metabolic rate or to a higher surface-area-to-volume ratio compared to larger embryos. Uptake in embryos was not influenced by male size, embryonic developmental advancement or position in the brood pouch. It is concluded that brooding males provide amino acids, and probably also glucose, to the developing embryos in the brood pouch.

  • 92. Lailvaux, Simon P.
    et al.
    Zajitschek, Felix
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Dessman, Josephine
    Brooks, Robert
    Differential aging of bite and jump performance in virgin and mated Teleogryllus Commodus crickets2011In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 65, no 11, p. 3138-3147Article in journal (Refereed)
    Abstract [en]

    Evolutionary theories of aging state that the force of natural selection declines with age, resulting in trait senescence. However, sexual selection theory predicts that costly traits that signal mate value should increase in expression as survival prospects decline. Mortality rates and fertility tend to show strong signatures of senescence, whereas sexual signaling traits increase with age, but how the expression of traits such as whole-organism performance measures that are subject to both sexual and nonsexual selection should change with age is unclear. We examined the effects of both a key life-history event (mating) and diet quality (male and female optimal diets) on aging in two whole-organism performance traits (bite force and jump take-off velocity) in male and female Teleogryllus commodus crickets. We found no evidence for diet effects on any of the measured traits. Aging effects were more evident in females than in males for both jumping and biting, and constitute a mix of senescence and terminal investment patterns depending on sex/mating class. Sex and mating therefore have important implications for resource allocation to performance traits, and hence for aging of those traits, and interactions between these two factors can result in complex changes in trait expression over individual lifetimes.

  • 93. Lambrechts, Marcel M.
    et al.
    Adriaensen, Frank
    Ardia, Daniel R.
    Artemyev, Alexandr V.
    Atienzar, Francisco
    Banbura, Jerzy
    Barba, Emilio
    Bouvier, Jean-Charles
    Camprodon, Jordi
    Cooper, Caren B.
    Dawson, Russell D.
    Eens, Marcel
    Eeva, Tapio
    Faivre, Bruno
    Garamszegi, Laszlo Z.
    Goodenough, Anne E.
    Gosler, Andrew G.
    Gregoire, Arnaud
    Griffith, Simon C.
    Gustafsson, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Johnson, L. Scott
    Kania, Wojciech
    Keiss, Oskars
    Llambias, Paulo E.
    Mainwaring, Mark C.
    Mand, Raivo
    Massa, Bruno
    Mazgajski, Tomasz D.
    Möller, Anders Pape
    Moreno, Juan
    Naef-Daenzer, Beat
    Nilsson, Jan-Åke
    Norte, Ana C.
    Orell, Markku
    Otter, Ken A.
    Park, Chan Ryul
    Perrins, Christopher M.
    Pinowski, Jan
    Porkert, Jiri
    Potti, Jaime
    Remes, Vladimir
    Richner, Heinz
    Rytkonen, Seppo
    Shiao, Ming-Tang
    Silverin, Bengt
    Slagsvold, Tore
    Smith, Henrik G.
    Sorace, Alberto
    Stenning, Martyn J.
    Stewart, Ian
    Thompson, Charles F.
    Tryjanowski, Piotr
    Torok, Janos
    van Noordwijk, Arie J.
    Winkler, David W.
    Ziane, Nadia
    The design of artificial nestboxes for the study of secondary hole-nesting birds: a review of methodological inconsistencies and potential biases2010In: Acta Ornithologica, ISSN 0001-6454, E-ISSN 1734-8471, Vol. 45, no 1, p. 1-26Article in journal (Refereed)
    Abstract [en]

    The widespread use of artificial nestboxes has led to significant advances in our knowledge of the ecology, behaviour and physiology of cavity nesting birds, especially small passerines Nestboxes have made it easier to perform routine monitoring and experimental manipulation of eggs or nestlings, and also repeatedly to capture, identify and manipulate the parents However, when comparing results across study sites the use of nestboxes may also Introduce a potentially significant confounding variable in the form of differences in nestbox design amongst studies, such as their physical dimensions, placement height, and the way in which they are constructed and maintained However, the use of nestboxes may also introduce an unconsidered and potentially significant confounding variable clue to differences in nestbox design amongst studies, such as their physical dimensions, placement height, and the way in which they are constructed and maintained Here we review to what extent the characteristics of artificial nestboxes (e g size, shape, construction material, colour) are documented in the 'methods' sections of publications involving hole-nesting passerine birds using natural or excavated cavities or artificial nestboxes for reproduction and roosting Despite explicit previous recommendations that authors describe in detail the characteristics of the nestboxes used, we found that the description of nestbox characteristics in most recent publications remains poor and insufficient We therefore list the types of descriptive data that should be included in the methods sections of relevant manuscripts and justify this by discussing how variation in nestbox characteristics can affect or confound conclusions from nestbox studies We also propose several recommendations to improve the reliability and usefulness of research based on long-term studies of any secondary hole-nesting species using artificial nestboxes for breeding or roosting.

  • 94. Landis, Susanne H.
    et al.
    Sundin, Josefin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Rosenqvist, Gunilla
    Roth, Olivia
    Behavioral adjustments of a pipefish to bacterial Vibrio challenge2012In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 66, no 10, p. 1399-1405Article in journal (Refereed)
    Abstract [en]

    Animals can profit from increasing temperatures by prolonged breeding seasons and faster growth rates. However, these fitness benefits are traded off against higher parasite load and increased virulence of temperature-sensitive pathogens. In thermally stratified habitats, behavioral plasticity can allow hosts to choose the optimal temperature to enhance individual fitness and to escape parasite pressure. To test this idea, we performed a temperature choice experiment with the host-parasite system of the sex-role reversed broad-nosed pipefish (Syngnathus typhle) and its bacterial pathogen Vibrio spp. In this species, pregnant males are expected to face a trade-off between shortening their brooding period in warm water and decreasing the effect of the infection in cold water. We found that exposure to Vibrio changed the temperature preference for both pregnant and nonpregnant males, as well as females compared to nonchallenged fish that tended to prefer warm water. This study shows that behavioral plasticity is one option for avoidance of higher bacterial prevalence, as expected due to rising ocean temperatures.

  • 95. Legrand, Delphine
    et al.
    Guillaume, Olivier
    Baguette, Michel
    Cote, Julien
    Trochet, Audrey
    Calvez, Olivier
    Zajitschek, Susanne
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Zajitschek, Felix
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Lecomte, Jane
    Benard, Quentin
    Le Galliard, Jean-Francois
    Clobert, Jean
    The Metatron: an experimental system to study dispersal and metaecosystems for terrestrial organisms2012In: Nature Methods, ISSN 1548-7091, E-ISSN 1548-7105, Vol. 9, no 8, p. 828-+Article in journal (Refereed)
    Abstract [en]

    Dispersal of organisms generates gene flow between populations. Identifying factors that influence dispersal will help predict how species will cope with rapid environmental change. We developed an innovative infrastructure, the Metatron, composed of 48 interconnected patches, designed for the study of terrestrial organism movement as a model for dispersal. Corridors between patches can be flexibly open or closed. Temperature, humidity and illuminance can be independently controlled within each patch. The modularity and adaptability of the Metatron provide the opportunity for robust experimental design for the study of 'meta-systems'. We describe a pilot experiment on populations of the butterfly Pieris brassicae and the lizard Zootoca vivipara in the Metatron. Both species survived and showed both disperser and resident phenotypes. The Metatron offers the opportunity to test theoretical models in spatial ecology.

  • 96.
    Lindqvist, Charlotte
    et al.
    Gotland University, Department of Biology.
    Sundin, Josefin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Berglund, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Rosenqvist, Gunilla
    Gotland University, School of Culture, Energy and Environment.
    Male broad-nosed pipefish Syngnathus typhle do not locate females by smell2011In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 78, no 6, p. 1861-1867Article in journal (Refereed)
    Abstract [en]

    Broad-nosed pipefish Syngnathus typhle were used to investigate whether males used scent in their search for mates. When the males in an experiment had access to olfactory cues only, they did not locate females better than they located males. Thus, S. typhle, was less successful in mate search when visual cues were absent.

  • 97.
    Lisney, Thomas J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Ekesten, Björn
    Tauson, Ragnar
    Håstad, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Ödeen, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Using electroretinograms to assess flicker fusion frequency in domestic hens Gallus gallus domesticus2012In: Vision Research, ISSN 0042-6989, E-ISSN 1878-5646, Vol. 62, p. 125-133Article in journal (Refereed)
    Abstract [en]

    The assessment of flicker fusion frequency (FFF), the stimulus frequency at which a flickering light stimulus can no longer be resolved and appears continuous, and critical flicker fusion frequency (CFF; the highest frequency at any light intensity that an observer can resolve flicker) are useful methods for comparing temporal resolution capabilities between animals. Behavioural experiments have found that average CFFs in domestic chickens (Gallus gallus domesticus) are in the range of ca. 75-87 Hz, measured in response to full spectrum (i.e. white light plus UV) stimuli. In order to examine whether the chicken retina is able to detect flicker at higher frequencies, we used electroretinograms (ERGs) to assess FFF/CFF in adult hens from two commercial genotypes, Lohmann Selected Leghorns (LSLs) and Lohmann Browns (LBs). ERGs were recorded in response to flickering light at ten full spectrum light intensities ranging from 0.7 to 2740 cd m(-2). Two methods were used to determine FFF/CFF from the ERG recordings and these methods yielded very similar results, with average FFF ranging from ca. 20 Hz at 0.7 cd m(-2) to an average CFF of ca. 105 Hz at 2740 cd m(-2). In some individuals, CFFs of 118-119 Hz were recorded. The Intensity/FFF (I/FFF) curves are double-branched with a break point representing the rod-cone transition occurring between 2.5 and 5.9 cd m(-2). No significant differences in the I/FFF curves were found between the two genotypes. At stimulus light intensities >250 cd m(-2), the ERG-derived FFF and CFF values are all higher than those from behavioural studies using the same stimuli. Although hens do not appear to be able to consciously perceive flicker above approximately 90 Hz, the finding that the ERG responses are able to remain in phase with light flickering at frequencies >100 Hz means that the retinae of domestic poultry housed in artificial light conditions may be able to resolve flicker from fluorescent lamps. As range of detrimental effects have been reported in humans as a result of exposure to such "invisible flicker", the possibility exists that flicker from fluorescent lamps also acts as stressor in domesticated birds.

  • 98.
    Lisney, Thomas J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Hawryshyn, Craig W.
    Ocular dimensions and cone photoreceptor topography in adult Nile Tilapia Oreochromis niloticus2010In: Environmental Biology of Fishes, ISSN 0378-1909, E-ISSN 1573-5133, Vol. 88, no 4, p. 369-376Article in journal (Refereed)
    Abstract [en]

    Information on the anatomy of the eye and the topography of cone photoreceptor cells in the retina is presented for the Nile Tilapia (Oreochromis niloticus). In adults, the shape and proportions of the ocular components of the prominent eye conform to the general form of fish eyes, as determined using cryo-sectioned eyes. The lens is approximately spherical and there is little variation in the distance from the centre of the lens to the border between the choroid and retina at a range of angles about the optical axis. The average ratio of the distance from the centre of the lens to the retina: lens radius (Matthiessen's ratio) is 2.44:1. In retinal wholemounts, single and double (twin) cone photoreceptors, forming a square mosaic, are present. Peak photoreceptor densities for both morphological cone types are found in the temporal retina. Using peak cone densities and estimates of focal length from cryo-sectioned eyes, visual acuity is calculated to be 5.44 cycles per deg. The lack of apparent specific ocular or retinal specializations and the relatively low visual acuity reflect the lifestyle of the Nile Tilapia and may allow it to adapt to changes in visual environment in its highly variable natural habitat as well as contributing to the 'ecological flexibility' of this species.

  • 99.
    Lisney, Thomas J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Rubene, Diana
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Rozsa, Jani
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Løvlie, Hanne
    Håstad, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Ödeen, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Behavioural assessment of flicker fusion frequency in chicken Gallus gallus domesticus2011In: Vision Research, ISSN 0042-6989, E-ISSN 1878-5646, Vol. 51, no 12, p. 1324-1332Article in journal (Refereed)
    Abstract [en]

    To interact with its visual environment, an organism needs to perceive objects in both space and time. High temporal resolution is hence important to the fitness of diurnally active animals, not least highly active aerial species such as birds. However, temporal resolution, as assessed by flicker fusion frequency (FFF; the stimulus frequency at which a flickering light stimulus can no longer be resolved and appears continuous) or critical flicker fusion frequency (CFF; the highest flicker fusion frequency at any light intensity) has rarely been assessed in birds. In order to further our understanding of temporal resolution as a function of light intensity in birds we used behavioural experiments with domestic chickens (Gallus gallus domesticus) from an old game breed 'Gammalsvensk dvarghona' (which is morphologically and behaviourally similar to the wildtype ancestor, the red jungle fowl, G. gallus), to generate an 'Intensity/FFF curve' (I/FFF curve) across full spectrum light intensities ranging from 0.2 to 2812 cd m(-2). The I/FFF curve is double-branched, resembling that of other chordates with a duplex retina of both rods and cones. Assuming that the branches represent rod and cone mediated responses respectively, the break point between them places the transition between scotopic and photopic vision at between 0.8 and 1.9 cd m(-2). Average FFF ranged from 19.8 Hz at the lowest light intensity to a CFF 87.0 Hz at 1375 cd m(-2). FFF dropped slightly at the highest light intensity. There was some individual variation with certain birds displaying CFFs of 90-100 Hz. The FFF values demonstrated by this non-selected breed appear to be considerably higher than other behaviourally derived FFF values for similar stimuli reported for white and brown commercial laying hens, indicating that the domestication process might have influenced temporal resolution in chicken.

  • 100. Lohmus, Mare
    et al.
    Moalem, Sharon
    Björklund, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Leptin, a tool of parasites?2012In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 8, no 5, p. 849-852Article in journal (Refereed)
    Abstract [en]

    One common physiological phenomenon that is involved both in infectious and in malignant processes is the reduction in appetite: disease anorexia. An increase in plasma levels of leptin with inflammation is thought to be involved in this process. However, from an evolutionary perspective, in certain cases, it would be more adaptive for an internal parasite to stimulate the appetite of the host instead of causing its suppression. We tested whether a parasitic infection with the larvae of the helminth parasite Taenia taeniaformis affects the levels of appetite-regulating proteins, such as leptin, ghrelin and neuropeptide-Y (NPY) in wild yellow-necked mouse (Apodemus flavicollis). We found that infected mice had lower plasma levels of leptin and increased levels of NPY than the uninfected subjects. Ghrelin levels were not associated with the occurrence of the parasites; however, these levels strongly correlated with the levels of NPY. This study suggests a possible manipulation by parasitic larvae of appetite regulation in infected subjects.

1234 51 - 100 of 168
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf