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  • 851.
    Zwoinska, Martyna K.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Age-specific trade-offs in life-history evolution2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Trade-offs prevent selection from driving all fitness-enhancing traits towards values that would maximize fitness. Life-history trade-offs, such as the one between survival and reproduction are well-studied, yet trade-offs can also involve behavioural or cognitive traits. Because males and females have different routes to successful reproduction, the optimal resolution of life-history trade-offs can differ between the sexes. However, shared genome can constrain the evolution of sex-specific adaptations. In this thesis, I explore the links between sex-specific life histories, cognition and behaviour. I start by linking sex differences in life histories to sex differences in learning performance in the outcrossing nematode Caenorhabditis remanei (Paper I). I report that age-related learning differs between the sexes and that it corresponds to sexual dimorphism in life history. Then, I use experimental evolution to select for learning performance to study the patterns of genetic correlations between learning and life-history traits in both sexes (Paper II). The results demonstrate the correlated evolution of sexual dimorphism in life history indicating sex-specific fitness costs and benefits of learning. In Paper III I use the fruit fly Drosophila melanogaster to ask about the extent to which cognitive and demographic aging are independent. The results reveal that selection for late-life reproduction alone bears no effect on late-life learning and that joint selection on late-life learning and reproduction does not yield lifespan benefits. The selection might have affected, however, female age-specific reproductive effort. Motivated by the questions on aging I proceed to ask why a potent lifespan extending drug – rapamycin affects sexes differently (Paper IV). I take a closer look at the trade-off between growth, lifespan and reproduction and propose that the sex experiencing a stronger relationship between size and fitness pays a higher cost of lifespan extension. Finally, I focus on another sex-specific trait – dispersal (Paper V). I conduct experimental evolution to uncover a negative genetic correlation between dispersal and reproduction and show sex-specific genetic variation for dispersal. In summary, my thesis unravels the complex pattern of interdependence between life-history, behavioural and cognitive traits, where sex emerges as an important factor that can maintain genetic variation for trade-offs.

    Delarbeten
    1. Sex differences in cognitive ageing: Testing predictions derived from life-history theory in a dioecious nematode
    Öppna denna publikation i ny flik eller fönster >>Sex differences in cognitive ageing: Testing predictions derived from life-history theory in a dioecious nematode
    2013 (Engelska)Ingår i: Experimental Gerontology, ISSN 0531-5565, E-ISSN 1873-6815, Vol. 48, nr 12, s. 1469-1472Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Life-history theory maintains that organisms allocate limited resources to different traits to maximize fitness. Learning ability and memory are costly and known to trade-off with longevity in invertebrates. However, since the relationship between longevity and fitness often differs between the sexes, it is likely that sexes will differentially resolve the trade-off between learning and longevity. We used an established associative learning paradigm in the dioecious nematode Caenorhabditis remanei, which is sexually dimorphic for lifespan, to study age-related learning ability in males and females. In particular, we tested the hypothesis that females (the shorter-lived sex) show higher learning ability than males early in life but senesce faster. Indeed, young females outperformed young males in learning a novel association between an odour (butanone) and food (bacteria). However, while learning ability and offspring production declined rapidly with age in females, males maintained high levels of these traits until mid-age. These results not only demonstrate sexual dimorphismin age-related learning ability but also suggest that it conforms to predictions derived from the life-history theory.

    Nyckelord
    Ageing, Caenorhabditis, Learning, Life-history, Sex differences, Trade-off
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-213468 (URN)10.1016/j.exger.2013.09.008 (DOI)000327489800012 ()
    Tillgänglig från: 2013-12-30 Skapad: 2013-12-23 Senast uppdaterad: 2017-12-06Bibliografiskt granskad
    2. Selection on learning performance results in the correlated evolution of sexual dimorphism in life history
    Öppna denna publikation i ny flik eller fönster >>Selection on learning performance results in the correlated evolution of sexual dimorphism in life history
    Visa övriga...
    2016 (Engelska)Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 70, nr 2, s. 342-357Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The evolution of learning can be constrained by trade-offs. As male and female life histories often diverge, the relationship between learning and fitness may differ between the sexes. However, because sexes share much of their genome, intersexual genetic correlations can prevent males and females from reaching their sex-specific optima resulting in intralocus sexual conflict (IaSC). To investigate if IaSC constraints sex-specific evolution of learning, we selected Caenorhabditis remanei nematode females for increased or decreased olfactory learning performance and measured learning, life span (in mated and virgin worms), reproduction, and locomotory activity in both sexes. Males from downward-selected female lines had higher locomotory activity and longer virgin life span but sired fewer progeny than males from upward-selected female lines. In contrast, we found no effect of selection on female reproduction and downward-selected females showed higher locomotory activity but lived shorter as virgins than upward-selected females. Strikingly, selection on learning performance led to the reversal of sexual dimorphism in virgin life span. We thus show sex-specific trade-offs between learning, reproduction, and life span. Our results support the hypothesis that selection on learning performance can shape the evolution of sexually dimorphic life histories via sex-specific genetic correlations.

    Nyckelord
    Caenorhabditis, cognition, intralocus sexual conflict, olfactory learning, sex-specific life histories
    Nationell ämneskategori
    Evolutionsbiologi
    Identifikatorer
    urn:nbn:se:uu:diva-282325 (URN)10.1111/evo.12862 (DOI)000370662500007 ()26787139 (PubMedID)
    Tillgänglig från: 2016-04-05 Skapad: 2016-04-05 Senast uppdaterad: 2017-11-30Bibliografiskt granskad
    3. Experimental evolution of slowed cognitive aging in Drosophila melanogaster
    Öppna denna publikation i ny flik eller fönster >>Experimental evolution of slowed cognitive aging in Drosophila melanogaster
    2017 (Engelska)Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 71, nr 3, s. 662-670Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Reproductive output and cognitive performance decline in parallel during aging, but it is unknown whether this reflects a shared genetic architecture or merely the declining force of natural selection acting independently on both traits. We used experimental evolution in Drosophila melanogaster to test for the presence of genetic variation for slowed cognitive aging, and assess its independence from that responsible for other traits' decline with age. Replicate experimental populations experienced either joint selection on learning and reproduction at old age (Old + Learning), selection on late-life reproduction alone (Old), or a standard two-week culture regime (Young). Within 20 generations, the Old + Learning populations evolved a slower decline in learning with age than both the Old and Young populations, revealing genetic variation for cognitive aging. We found little evidence for a genetic correlation between cognitive and demographic aging: although the Old + Learning populations tended to show higher late-life fecundity than Old populations, they did not live longer. Likewise, selection for late reproduction alone did not result in improved late-life learning. Our results demonstrate that Drosophila harbor genetic variation for cognitive aging that is largely independent from genetic variation for demographic aging and suggest that these two aspects of aging may not necessarily follow the same trajectories.

    Ort, förlag, år, upplaga, sidor
    WILEY, 2017
    Nyckelord
    Cognitive aging, Drosophila, experimental evolution, genetic architecture, learning, trade-off
    Nationell ämneskategori
    Genetik
    Identifikatorer
    urn:nbn:se:uu:diva-320841 (URN)10.1111/evo.13156 (DOI)000396039000011 ()28000915 (PubMedID)
    Forskningsfinansiär
    Kungliga VetenskapsakademienVetenskapsrådetEU, Europeiska forskningsrådet
    Tillgänglig från: 2017-04-26 Skapad: 2017-04-26 Senast uppdaterad: 2017-09-07Bibliografiskt granskad
    4. Sex-specific Tradeoffs With Growth and Fitness Following Life-span Extension by Rapamycin in an Outcrossing Nematode, Caenorhabditis remanei
    Öppna denna publikation i ny flik eller fönster >>Sex-specific Tradeoffs With Growth and Fitness Following Life-span Extension by Rapamycin in an Outcrossing Nematode, Caenorhabditis remanei
    Visa övriga...
    2016 (Engelska)Ingår i: The journals of gerontology. Series A, Biological sciences and medical sciences, ISSN 1079-5006, E-ISSN 1758-535X, Vol. 71, nr 7, s. 882-890Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Rapamycin inhibits the nutrient-sensing TOR pathway and extends life span in a wide range of organisms. Although life-span extension usually differs between the sexes, the reason for this is poorly understood. Because TOR influences growth, rapamycin likely affects life-history traits such as growth and reproduction. Sexes have different life-history strategies, and theory predicts that they will resolve the tradeoffs between growth, reproduction, and life span differently. Specifically, in taxa with female-biased sexual size dimorphism, reduced growth may have smaller effects on male fitness. We investigated the effects of juvenile, adult, or life-long rapamycin treatment on growth, reproduction, life span, and individual fitness in the outcrossing nematode Caenorhabditis remanei. Life-long exposure to rapamycin always resulted in the strongest response, whereas postreproductive exposure did not affect life span. Although rapamycin resulted in longer life span and smaller size in males, male individual fitness was not affected. In contrast, size and fitness were negatively affected in females, whereas life span was only extended under high rapamycin concentrations. Our results support the hypothesis that rapamycin affects key life-history traits in a sex-specific manner. We argue that the fitness cost of life-span extension will be sex specific and propose that the smaller sex generally pay less while enjoying stronger life-span increase.

    Nyckelord
    Antiaging, Evolution, Longevity
    Nationell ämneskategori
    Biologiska vetenskaper
    Identifikatorer
    urn:nbn:se:uu:diva-304528 (URN)10.1093/gerona/glv174 (DOI)000381209900006 ()26472877 (PubMedID)
    Forskningsfinansiär
    Vetenskapsrådet, C0636601, 621-2013-4828EU, Europeiska forskningsrådet, St-G 2010 AGINGSEXDIFF 260885
    Tillgänglig från: 2016-10-12 Skapad: 2016-10-06 Senast uppdaterad: 2017-11-29Bibliografiskt granskad
    5. Fitness-associated dispersal: selection for increased dispersal results in lower fitness
    Öppna denna publikation i ny flik eller fönster >>Fitness-associated dispersal: selection for increased dispersal results in lower fitness
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nyckelord
    fitness-associated dispersal, dispersal syndromes, artificial selection, life-history theory, Caenorhabdtitis
    Nationell ämneskategori
    Naturvetenskap
    Forskningsämne
    Biologi med inriktning mot zooekologi
    Identifikatorer
    urn:nbn:se:uu:diva-329033 (URN)
    Tillgänglig från: 2017-09-06 Skapad: 2017-09-06 Senast uppdaterad: 2017-09-07
  • 852.
    Zwoinska, Martyna K.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Kolm, Niclas
    Maklakov, Alexei A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Sex differences in cognitive ageing: Testing predictions derived from life-history theory in a dioecious nematode2013Ingår i: Experimental Gerontology, ISSN 0531-5565, E-ISSN 1873-6815, Vol. 48, nr 12, s. 1469-1472Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Life-history theory maintains that organisms allocate limited resources to different traits to maximize fitness. Learning ability and memory are costly and known to trade-off with longevity in invertebrates. However, since the relationship between longevity and fitness often differs between the sexes, it is likely that sexes will differentially resolve the trade-off between learning and longevity. We used an established associative learning paradigm in the dioecious nematode Caenorhabditis remanei, which is sexually dimorphic for lifespan, to study age-related learning ability in males and females. In particular, we tested the hypothesis that females (the shorter-lived sex) show higher learning ability than males early in life but senesce faster. Indeed, young females outperformed young males in learning a novel association between an odour (butanone) and food (bacteria). However, while learning ability and offspring production declined rapidly with age in females, males maintained high levels of these traits until mid-age. These results not only demonstrate sexual dimorphismin age-related learning ability but also suggest that it conforms to predictions derived from the life-history theory.

  • 853.
    Zwoinska, Martyna K.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Lind, Martin I.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Cortazar-Chinarro, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Ramsden, Mark
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Maklakov, Alexei A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Selection on learning performance results in the correlated evolution of sexual dimorphism in life history2016Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 70, nr 2, s. 342-357Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The evolution of learning can be constrained by trade-offs. As male and female life histories often diverge, the relationship between learning and fitness may differ between the sexes. However, because sexes share much of their genome, intersexual genetic correlations can prevent males and females from reaching their sex-specific optima resulting in intralocus sexual conflict (IaSC). To investigate if IaSC constraints sex-specific evolution of learning, we selected Caenorhabditis remanei nematode females for increased or decreased olfactory learning performance and measured learning, life span (in mated and virgin worms), reproduction, and locomotory activity in both sexes. Males from downward-selected female lines had higher locomotory activity and longer virgin life span but sired fewer progeny than males from upward-selected female lines. In contrast, we found no effect of selection on female reproduction and downward-selected females showed higher locomotory activity but lived shorter as virgins than upward-selected females. Strikingly, selection on learning performance led to the reversal of sexual dimorphism in virgin life span. We thus show sex-specific trade-offs between learning, reproduction, and life span. Our results support the hypothesis that selection on learning performance can shape the evolution of sexually dimorphic life histories via sex-specific genetic correlations.

  • 854.
    Zwoinska, Martyna K.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi. Univ Lausanne, Dept Ecol & Evolut, CH-1015 Lausanne, Switzerland..
    Maklakov, Alexei A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Kawecki, Tadeusz J.
    Univ Lausanne, Dept Ecol & Evolut, CH-1015 Lausanne, Switzerland..
    Hollis, Brian
    Univ Lausanne, Dept Ecol & Evolut, CH-1015 Lausanne, Switzerland.;Ecole Polytech Fed Lausanne, Sch Life Sci, Lausanne, Switzerland..
    Experimental evolution of slowed cognitive aging in Drosophila melanogaster2017Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 71, nr 3, s. 662-670Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reproductive output and cognitive performance decline in parallel during aging, but it is unknown whether this reflects a shared genetic architecture or merely the declining force of natural selection acting independently on both traits. We used experimental evolution in Drosophila melanogaster to test for the presence of genetic variation for slowed cognitive aging, and assess its independence from that responsible for other traits' decline with age. Replicate experimental populations experienced either joint selection on learning and reproduction at old age (Old + Learning), selection on late-life reproduction alone (Old), or a standard two-week culture regime (Young). Within 20 generations, the Old + Learning populations evolved a slower decline in learning with age than both the Old and Young populations, revealing genetic variation for cognitive aging. We found little evidence for a genetic correlation between cognitive and demographic aging: although the Old + Learning populations tended to show higher late-life fecundity than Old populations, they did not live longer. Likewise, selection for late reproduction alone did not result in improved late-life learning. Our results demonstrate that Drosophila harbor genetic variation for cognitive aging that is largely independent from genetic variation for demographic aging and suggest that these two aspects of aging may not necessarily follow the same trajectories.

  • 855.
    Zwoinska, Martyna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Larva, Tuuli
    Sekajova, Zuzana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Carlsson, Hanne
    Meurling, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Maklakov, Alexei
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Fitness-associated dispersal: selection for increased dispersal results in lower fitnessManuskript (preprint) (Övrigt vetenskapligt)
  • 856.
    Zwoinska, Martyna
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Lind, Martin I.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Maklakov, Alexei A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Sexual Conflict: Male Control of Female Longevity2014Ingår i: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 24, nr 5, s. R196-R198Artikel i tidskrift (Övrigt vetenskapligt)
  • 857.
    Ålund, Murielle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Gametes and speciation: from prezygotic to postzygotic isolation2012Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Speciation lies at the heart of evolutionary biology and researchers have been trying to understand the mechanisms leading to the evolution of reproductive isolation since over 250 years. Premating barriers (i.e. barriers preventing heterospecific individuals to mate with each other) and extrinsic postzygotic isolation (i.e. environmental factors affecting the fitness of hybrid individuals) have been studied in many taxa. However, little is known about what is happening at the gametic level, both before heterospecific fertilization (i.e. postmating prezygotic or gametic isolation) and in hybrid individuals (i.e. intrinsic postzygotic incompatibilities). In this essay, I will give an overview of the role gametes play in the evolution of reproductive isolation. I conclude that gametes and reproductive proteins evolve quickly, under strong influence of sexual and sexually antagonistic selection. Gametes are very diverse between species and sperm competition and female cryptic choice can lead to higher fertilization success of sperm from conspecific males. In the hybrid offspring, spermatogenesis can be easily disturbed by small differences in gene expression and this leads to a greater number of genes causing hybrid sterility compared to hybrid inviability among taxa. Following Haldane’s rule, the heterogametic sex is the first to be affected by hybrid incompatibilities, but different mechanisms seem to cause inviability and sterility and taxa with heterogametic males or heterogametic females might be affected differently. I end this review by focusing on one particular model system for studying speciation: the Ficedula flycatchers. Much is known about the ecological factors affecting speciation and hybridization between pied and collared flycatchers and new molecular data give insights into the genetics of speciation, but the role of gametes has not been studied in this system. Studies on gamete divergence and hybrid gamete production in the flycatchers will allow us to get a better idea of the role of gametes in speciation in a wild organism with homogametic males.

  • 858.
    Ålund, Murielle
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Rice, Amber M.
    Qvarnström, Anna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Low fertility of wild hybrid male flycatchers despite recent divergence2013Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, nr 3, artikel-id 20130169Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Postzygotic isolation may be important for maintaining species boundaries, particularly when premating barriers are incomplete. Little is known about the course of events leading from minor environmental mismatches affecting hybrid fitness to severe genetic incompatibilities causing sterility or inviability. We investigated whether reduced reproductive success of hybrid males was caused by suboptimal sperm traits or by more severe genetic incompatibilities in a hybrid zone of pied (Ficedula hypoleuca) and collared flycatchers (F. albicollis) on the island of Oland, Sweden. About 4 per cent hybridization is observed in this population and all female hybrids are sterile. We found no sperm in the ejaculates of most sampled hybrid males, and sperm with abnormal morphology in two hybrids. Furthermore, none of the hybrids sired any offspring because of high levels of hatching failure and extra-pair paternity in their nests. These results from a natural hybrid zone suggest that the spermatogenesis of hybrid males may become disrupted despite little genetic divergence between the parental species.

  • 859.
    Ålund, Murielle
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi. Michigan State Univ, Dept Integrat Biol, Giltner Hall 362, E Lansing, MI 48825 USA.
    Persson Schmiterlöw, Siri
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    McFarlane, S. Eryn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi. Univ Edinburgh, Inst Evolutionary Biol, Charlotte Auerbach Rd, Edinburgh EH9 3FL, Midlothian, Scotland.
    Qvarnström, Anna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Optimal sperm length for high siring success depends on forehead patch size in collared flycatchers2018Ingår i: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 29, nr 6, s. 1436-1443Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dominance over rivals, sexual attractiveness, and highly efficient ejaculates are 3 important contributors of male fertilization success but theories about how primary and secondary sexual characters may co-evolve largely remain to be tested. We investigated how variation in a sexual signal (forehead patch size) and sperm morphology jointly affected siring success of 70 males in a natural population of collared flycatchers. We show that the optimal sperm length to attain high relative fertilization success depended on the size of a male's secondary sexual character. Males with small forehead patches sired more offspring in their nest when they produced long sperm and vice-versa. These results are not compatible with theories based on simple relationships between display traits and sperm "quality" but imply that the optimal fertilization strategy (and hence optimal sperm traits) differs between males even in a predominantly socially monogamous population with moderate extra-pair paternity rates. Thus, a better knowledge of the complex chain of behavioural interactions between the sexes and their gametes is needed for a complete understanding of how sexual selection operates in nature.

  • 860.
    Ålund née Podevin, Murielle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Sex, Sperm and Speciation: On sexual selection and fertility in hybridizing flycatchers2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Sexual reproduction entails complex co-evolution between the sexes, necessary for successful fertilization, ensuring individual and population-level fitness. Interfertility is the main criterion for species definition and understanding speciation requires detailed studies of reproductive barriers. However, many studies on reproductive barriers are constrained to infer evolutionary processes from patterns. In this thesis, I focus on a hybrid zone between collared and pied flycatchers (Ficedula albicollis and hypoleuca) on the island of Öland, and a trait that is essential for fertilization: sperm. Long-term monitoring of these species, combined with recent advances in molecular tools, allow me to study how complex on-going intersexual and interspecific interactions influence reproductive isolation in this young hybrid zone. I start by exploring the links between pre- and postmating sexual selection within collared flycatchers (paper I and II). I show that secondary sexual characters and indirect mate-choice benefits are tightly linked to physiology (paper I), and that a male’s attractiveness and dominance status dictate which sperm traits are optimal, as a male’s fertilization success depends on an interaction between sperm and display traits (paper II). I then report a source of strong postzygotic isolation between recently diverged collared and pied flycatchers: impaired spermatogenesis resulting in absence of mature sperm cells in hybrid males (paper III). I show however that pied flycatcher females, who are most exposed to hybridization, can mitigate these costs through mechanisms of cryptic female choice impairing heterospecific sperm performance, allowing them to bias paternity towards pure-species offspring (paper IV). Finally, by exploring the testes transcriptomes and sperm proteomes of both species, I highlight the importance of gene and protein regulation mechanisms in facilitating phenotypic divergence between these species (paper V). Thus, my thesis reveals complex interactions between primary and secondary sexual characters in a wild bird and suggests that mechanisms of sexual selection are tightly linked to essential physiological functions. I also show that genetic incompatibilities can evolve rapidly despite low genome-wide levels of divergence but that divergence in regulatory regions and proteins potentially allows fast evolution of molecular mechanisms impairing or preventing costly heterospecific fertilization. 

    Delarbeten
    1. Sexual selection affects climate adaptation in collared flycatchers
    Öppna denna publikation i ny flik eller fönster >>Sexual selection affects climate adaptation in collared flycatchers
    2017 (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The role of sexual selection in climate adaptation is debated. We tested whether sexual selection has the potential to speed up adaptation to thermal conditions in a natural population of collared flycatchers. Based on a three-year cross-fostering experiment, we found that the size of a sexually selected trait predicted offspring metabolic rate: male collared flycatchers with large forehead patches sired offspring with low metabolic rate regardless of the ambient temperature. Thus, there was a stable significant relationship between forehead patch size of genetic fathers and offspring metabolic rate. Nestlings with high metabolic rate experienced a survival advantage when growing under warm temperatures, while the opposite was true in cold environments. Our study shows that females can modulate their offspring’s physiology through mate choice, and that sexual selection can thus affect climate adaptation.

    Nyckelord
    sexual selection, climate adaptation, resting metabolic rate, Ficedula flycatcher, secondary sexual character, physiology
    Nationell ämneskategori
    Evolutionsbiologi
    Identifikatorer
    urn:nbn:se:uu:diva-322788 (URN)
    Tillgänglig från: 2017-07-30 Skapad: 2017-07-30 Senast uppdaterad: 2017-07-30
    2. Revisiting the definition of “sperm quality”: selection on sperm length depends on a male’s attractiveness and dominance in wild collared flycatchers
    Öppna denna publikation i ny flik eller fönster >>Revisiting the definition of “sperm quality”: selection on sperm length depends on a male’s attractiveness and dominance in wild collared flycatchers
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Dominance over rivals, sexual attractiveness and highly efficient ejaculates are all known to be essential for male fertilization success but the theories of how primary and secondary sexual characters may co-evolve largely remain to be tested. Here, we measure sperm morphology in 131 wild-caught collared flycatchers over a four-year period and investigate the links between male display traits, sperm characteristics and siring success among 425 offspring sired by 71 of these males. We show that the optimal sperm length to attain high relative fertilization success depends on the size of a male’s secondary sexual character. Males with small ornaments sire more offspring in their own nest when they produce long sperm and vice-versa. These results are not compatible with theories based on simple relationships between secondary sexual traits and sperm “quality” but imply that the optimal fertilization strategy (and hence optimal sperm traits) differ between males even in a predominantly socially monogamous population with moderate extra-pair copulation rates. Thus, a better knowledge of the complex chain of behavioural interactions between the sexes and their gametes is needed for a complete understanding of how sexual selection operates in nature.

    Nyckelord
    sperm morphology, secondary sexual character, mating strategy, fertilization success, Ficedula flycatcher, extra-pair copulation
    Nationell ämneskategori
    Evolutionsbiologi
    Identifikatorer
    urn:nbn:se:uu:diva-326808 (URN)
    Tillgänglig från: 2017-07-30 Skapad: 2017-07-30 Senast uppdaterad: 2017-07-30
    3. Low fertility of wild hybrid male flycatchers despite recent divergence
    Öppna denna publikation i ny flik eller fönster >>Low fertility of wild hybrid male flycatchers despite recent divergence
    2013 (Engelska)Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, nr 3, artikel-id 20130169Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Postzygotic isolation may be important for maintaining species boundaries, particularly when premating barriers are incomplete. Little is known about the course of events leading from minor environmental mismatches affecting hybrid fitness to severe genetic incompatibilities causing sterility or inviability. We investigated whether reduced reproductive success of hybrid males was caused by suboptimal sperm traits or by more severe genetic incompatibilities in a hybrid zone of pied (Ficedula hypoleuca) and collared flycatchers (F. albicollis) on the island of Oland, Sweden. About 4 per cent hybridization is observed in this population and all female hybrids are sterile. We found no sperm in the ejaculates of most sampled hybrid males, and sperm with abnormal morphology in two hybrids. Furthermore, none of the hybrids sired any offspring because of high levels of hatching failure and extra-pair paternity in their nests. These results from a natural hybrid zone suggest that the spermatogenesis of hybrid males may become disrupted despite little genetic divergence between the parental species.

    Nyckelord
    hybrid, sterility-infertility, flycatcher, sperm, postzygotic incompatibility
    Nationell ämneskategori
    Biologiska vetenskaper
    Identifikatorer
    urn:nbn:se:uu:diva-202341 (URN)10.1098/rsbl.2013.0169 (DOI)000318762300035 ()
    Tillgänglig från: 2013-06-24 Skapad: 2013-06-24 Senast uppdaterad: 2017-12-06Bibliografiskt granskad
    4. Females discriminate against heterospecific sperm in a natural hybrid zone
    Öppna denna publikation i ny flik eller fönster >>Females discriminate against heterospecific sperm in a natural hybrid zone
    Visa övriga...
    2016 (Engelska)Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 70, nr 8, s. 1844-1855Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    When hybridization is maladaptive, species-specific mate preferences are selectively favored, but low mate availability may constrain species-assortative pairing. Females paired to heterospecifics may then benefit by copulating with multiple males and subsequently favoring sperm of conspecifics. Whether such mechanisms for biasing paternity toward conspecifics act as important reproductive barriers in socially monogamous vertebrate species remains to be determined. We use a combination of long-term breeding records from a natural hybrid zone between collared and pied flycatchers (Ficedula albicollis and F. hypoleuca), and an in vitro experiment comparing conspecific and heterospecific sperm performance in female reproductive tract fluid, to evaluate the potential significance of female cryptic choice. We show that the females most at risk of hybridizing (pied flycatchers) frequently copulate with multiple males and are able to inhibit heterospecific sperm performance. The negative effect on heterospecific sperm performance was strongest in pied flycatcher females that were most likely to have been previously exposed to collared flycatcher sperm. We thus demonstrate that a reproductive barrier acts after copulation but before fertilization in a socially monogamous vertebrate. While the evolutionary history of this barrier is unknown, our results imply that there is opportunity for it to be accentuated via a reinforcement-like process.

    Nyckelord
    Cryptic female choice, hybrid zones, postcopulatory prezygotic barriers, reinforcement, speciation, sexual selection
    Nationell ämneskategori
    Evolutionsbiologi
    Identifikatorer
    urn:nbn:se:uu:diva-303102 (URN)10.1111/evo.12986 (DOI)000381205700013 ()
    Forskningsfinansiär
    Vetenskapsrådet, 621-2012-3722Kungliga Vetenskapsakademien
    Tillgänglig från: 2016-10-05 Skapad: 2016-09-15 Senast uppdaterad: 2018-08-10Bibliografiskt granskad
    5. Reproductive -omics of a wild avian speciation model unveils candidate genes for gamete interaction
    Öppna denna publikation i ny flik eller fönster >>Reproductive -omics of a wild avian speciation model unveils candidate genes for gamete interaction
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The complex nature of interspecific interactions contributing to reproductive isolation means that we still know little about their molecular basis. Male reproductive traits are notorious for their fast evolution at the phenotypic and genotypic level, and divergence in components of the ejaculate can lead to incompatibilities between closely related species. Making use of recent advances of molecular tools and the extensive knowledge on the biology and ecology of young sister species, here the pied (Ficedula hypoleuca) and collared flycatcher (F. albicollis), allows the identification of candidate phenotypes and the underlying genotypes maintaining species boundaries. Pied flycatcher females can avoid costly production of sterile hybrids when mated to collared flycatchers by cryptically favouring conspecific sperm. Here, we describe the testes transcriptome and sperm proteome of both species, confirm the complexity of avian sperm development and functions and identify several candidate genes for interactions between sperm and the female reproductive tract, using multiple independent measures of divergence between the species. We show that divergence at the transcriptional and translational levels can potentially lead to the evolution of reproductive incompatibilities despite low levels of sequence divergence, and suggest that integrating several -omics techniques with knowledge of the biology of naturally hybridizing species will greatly improve our understanding of the molecular basis of speciation in the near future. 

    Nyckelord
    Reproductive isolation, cryptic female choice, sperm, proteomics, transcriptomics, Ficedula flycatchers
    Nationell ämneskategori
    Evolutionsbiologi
    Identifikatorer
    urn:nbn:se:uu:diva-326809 (URN)
    Tillgänglig från: 2017-07-30 Skapad: 2017-07-30 Senast uppdaterad: 2017-07-30
  • 861.
    Ödeen, Anders
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Håstad, Olle
    Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, S-75007 Uppsala, Sweden..
    The phylogenetic distribution of ultraviolet sensitivity in birds2013Ingår i: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 13, s. 36-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Colour vision in birds can be categorized into two classes, the ultraviolet (UVS) and violet sensitive (VS). Their phylogenetic distributions have traditionally been regarded as highly conserved. However, the complicated nature of acquiring spectral sensitivities from cone photoreceptors meant that until recently, only a few species had actually been studied. Whether birds are UVS or VS can nowadays be inferred from a wide range of species via genomic sequencing of the UV/violet SWS1 cone opsin gene. Results: We present genomic sequencing results of the SWS1 gene from 21 avian orders. Amino acid residues signifying UV sensitivity are found in the two most important spectral tuning sites 86 and 90 of Pteroclidiformes and Coraciiformes, in addition to the major clades, Palaeognathae, Charadriiformes, Trogoniformes, Psittaciformes and Passeriformes, where they where previously known to occur. We confirm that the presumed UVS-conferring amino acid combination F86, C90 and M93 is common to Palaeognathae and unique to this clade, despite available spectrometric evidence showing the ostrich retina to be VS. Conclusions: By mapping our results together with data from previous studies on a molecular phylogeny we show that avian colour vision shifted between VS and UVS at least 14 times. Single nucleotide substitutions can explain all these shifts. The common ancestor of birds most likely had a VS phenotype. However, the ancestral state of the avian SWS1 opsin's spectral tuning sites cannot be resolved, since the Palaeognathae are F86, C90 while the Neognathae are ancestrally S86, S90. The phylogenetic distribution of UVS and VS colour vision in birds is so complex that inferences of spectral sensitivities from closely related taxa should be used with caution.

  • 862.
    Östman, Örjan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Langenheder, Silke
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Weak seasonality and synchrony among bacterial communities in small pools2013Ingår i: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 69, nr 3, s. 223-229Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Temporal dynamics of microbial communities show seasonal trends and synchronous dynamics between communities in different aquatic habitats, but previous studies have mainly focused on larger systems such as oceans, rivers, or lakes. However, a large part of aquatic water bodies consists of small pools, ponds, and streams, which tend to be environmentally heterogeneous over relatively small spatial scales. We studied a bacterial metacommunity of 16 rock pools at a spatial scale of 600 m2, which was sampled at approximately monthly intervals over the course of 1 yr. We show that temporal dynamics were not evidently synchronous between rock pools over time and that there was no clear seasonal pattern. The environmental variable that explained the most of the temporal dynamics in rock pools over time was water colour, which is often not the main variable explaining spatial differences in bacterial composition between pools. Our results suggest that temporal dynamics of bacterial communities both among and within small water bodies show markedly different patterns compared to larger previously investigated systems, presumably due to their larger heterogeneity and less synchronous environmental changes. 

  • 863.
    Östman, Örjan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Langenheder, Silke
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Weak seasonality and synchrony among bacterial communities in small pools2013Ingår i: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 69, nr 3, s. 223-229Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Temporal dynamics of microbial communities show seasonal trends and synchronous dynamics between communities in different aquatic habitats, but previous studies have mainly focused on larger systems such as oceans, rivers, or lakes. However, a large part of aquatic water bodies consists of small pools, ponds, and streams, which tend to be environmentally heterogeneous over relatively small spatial scales. We studied a bacterial metacommunity of 16 rock pools at a spatial scale of 600 m(2), which was sampled at approximately monthly intervals over the course of 1 yr. We show that temporal dynamics were not evidently synchronous between rock pools over time and that there was no clear seasonal pattern. The environmental variable that explained the most of the temporal dynamics in rock pools over time was water colour, which is often not the main variable explaining spatial differences in bacterial composition between pools. Our results suggest that temporal dynamics of bacterial communities both among and within small water bodies show markedly different patterns compared to larger previously investigated systems, presumably due to their larger heterogeneity and less synchronous environmental changes.

  • 864.
    Östman, Örjan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Wengström, Åsa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Gradin, Ulf
    Wissman, Jorgen
    Schafer, Martina
    Lundström, Jan O.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Lower abundance of flood water mosquito larvae in managed wet meadows in the lower Dalalven floodplains, Sweden2015Ingår i: Wetlands Ecology and Management, ISSN 0923-4861, E-ISSN 1572-9834, Vol. 23, nr 2, s. 257-267Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To investigate the effect of vegetation management on mosquito abundance on the floodplains of the River Dalalven, central Sweden, we studied abundance of floodwater mosquito larvae (mainly Aedes sticticus) using a paired design, comparing flooded wet meadows that were mowed or grazed by cattle to those that were unmanaged. Two floods occurred during the study year (2012), the first in conjunction with the spring flood in May and the second after heavy rainfall in July. We used the standard mosquito dipper to estimate mosquito larval abundance along transects from the shore towards permanent water on each meadow. The number of mosquito larvae was on average lower in each managed wet meadow compared to the corresponding unmanaged meadow, both in May (71 % reduction, SD = 28 %) and in July (35 % reduction, SD = 79 %). However, there was substantial variation in the difference between managed and unmanaged meadows among pairs. We measured water depth, temperature, estimated proportion of open water surface, soil nutrient levels and micro-topology. Some of the variation in larval abundance could be explained by differences in local conditions. Mosquito larval abundance increased with nutrient levels and occurrence of tussocks, and decreased with water depth and percentage open water surface, especially among unmanaged wetlands. This study suggests that mowing or grazing may reduce the abundance of floodwater mosquito larvae in flooded wet meadows. In addition, vegetation management seem to have the greatest effect on mosquito larval abundance in nutrient-rich wet meadows where tussocks are abundant.

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