Sökning: "polyandry"

Visar resultat 6 - 10 av 10 avhandlingar innehållade ordet polyandry.

  1. 6. Adaptive significance of queen mating frequency in ants : In search of benefits of genetic variability

    Författare :Pia J. Gertsch; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; Genetics; genetik;

    Sammanfattning : Fitness effects of polyandry, multiple mating by females, were studied on two ant speciesLasius niger and Formica truncorum. Particular emphasis was put on evaluating diploid male load, which happens when homozygosity in the sex determination locus leads to intendedfemales developing into sterile, diploid males. LÄS MER

  3. 7. Drivers of polymorphism dynamics in pygmy grasshoppers

    Författare :Jenny Johansson; Anders Forsman; Jacob Höglund; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Evolutionary Biology; Evolutionsbiologi;

    Sammanfattning : In this thesis, I used colour polymorphism in pygmy grasshoppers as a model system to study the influence of selection, developmental plasticity, mating behaviour and gene flow on patterns of phenotypic and genetic diversity within and among populations in changing environments.Data for more than 5,000 individuals collected from natural populations showed that the incidence of black (melanic) pygmy grasshoppers was higher in burnt than in non-burnt areas, and rapidly declined over time within populations in post-fire environments. LÄS MER

  4. 8. 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

  5. 9. Mating structure and nestmate relatedness in primitively social hymenoptera as revealed by microsatellites

    Författare :Peter A. Thorén; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Genetics; Genetik; Clinical genetics; Klinisk genetik; Genetics; genetik;

    Sammanfattning : Mating structure and nestmate relatedness have been estimated in social Hymenoptera with different levels of sociality. Microsatellite markers have been developed for both communal bees (Andrena scottica) and for primetively eusocial wasps (Vespula rufa). LÄS MER

  7. 10. Genetic variation and sexual reproduction in a moss with dwarf males, Homalothecium lutescens

    Författare :Frida Rosengren; Biodiversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bryophytes; mosses; dwarf males; sexual reproduction; genetic variation; genetic structure; inbreeding; isozymes; allozymes; SNP; sporophytes; spore; fertilization; fertility;

    Sammanfattning : Dwarf males occur in many unrelated groups of organisms. Among land plants they are unique to mosses. Moss dwarf males originate from male spores that land and germinate on the female where their final size is restricted to a few mm. Fertilization in mosses occur over short distances with swimming spermatozoids. LÄS MER