Sökning: "Sperm competition"

Visar resultat 1 - 5 av 15 avhandlingar innehållade orden Sperm competition.

  1. 1. Selection in sperm and its consequences : Exploring haploid selection, ageing and epigenetic effects in sperm

    Författare :Cosima Hermans Née Hotzy; Simone Immler; Göran Arnqvist; Mariana Wolfner; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; sperm; evolution; selection; haploid selection; epigenetics; sperm-mediated effects; trans-generational effects; sperm ageing; sperm senescence;

    Sammanfattning : Sexually reproducing eukaryotes are typically going through a biphasic life cycle with a diploid and a haploid phase. Unlike in plants where selection on haploid pollen genotypes is well established, the possibility of selection occurring in animal sperm is currently not known. LÄS MER

  3. 2. Choice, competition, and interactions between episodes of sexual selection

    Författare :Charel Reuland; John Fitzpatrick; Ingo Schlupp; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; contest competition; sperm competition; mate choice; cryptic choice; sperm quality; reproductive status; social dominance; etologi; Ethology;

    Sammanfattning : Choice and competition are essential parts of evolutionary biology. In an effort to pass their genes from one generation to the next, animals may carefully choose their mating partners, and/or compete for access to mates. LÄS MER

  4. 3. Gonad and ejaculate allocation in alternative reproductive tactics of salmon and trout with reference to sperm competition

    Författare :Tomislav Vladić; Michael Taborsky; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; alternative reproductive tactics; sperm competition; brown trout; Atlantic salmon; ATP; ejaculate expenditure; motility; sperm morphology; trade-off; loaded raffle; zoologi; Zoology;

    Sammanfattning : Atlantic salmon, Salmo salar L., and brown trout, Salmo trutta L., exhibit alternative male maturation phenotypes, anadromous and precociously mature parr, which commonly endure in sperm competition at the spawning grounds. LÄS MER

  5. 4. Sexual selection in Pomatoschistus – nests, sperm competition, and paternal care

    Författare :Ola Svensson; Charlotta Kvarnemo; Sigal Balshine; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Female choice; Filial cannibaism; Gobiidae; Nests; Paternal care; Pomatoschistus microps; Pomatoschistus minutus; Sexual selection; Sperm competition; Teleostei; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

    Sammanfattning : Sexual selection arises through variation in reproductive success. This thesis investigates different aspects important in sexual selection, namely nest building, sperm competition, paternity and paternal care, and their mutual interrelationships. LÄS MER

  7. 5. Life history evolution in a bivoltine butterfly

    Författare :Helena Larsdotter Mellström; Christer Wiklund; Klaus Fischer; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Bivoltine; Diapause; Lepidoptera; Life history; Mating system; Pheromone; Polyphenism; Population density; Sexual selection; Sperm competition; zoologisk ekologi; Animal Ecology;

    Sammanfattning : Evolution is not always straight-forward, as selection pressures may differ between different generations of the same species. This thesis focuses on the evolution of life history of the model species, the Green-veined White butterfly Pieris napi. In central Sweden P. napi has two generations per year. LÄS MER