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Showing result 1 - 5 of 22 swedish dissertations matching the above criteria.

  2. 1. The Preservation of Favoured Morphs in the Struggle Between Sexes

    Author : Thomas Gosden; Evolutionär ekologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Sexual Selection; Polymorphism; Density-dependence; Population divergence; Zygoptera; Sexual Conflict;

    Abstract : Sexual selection is particularly likely to promote population divergence, because sexual traits are expected to be subject to rapid evolutionary change. Identifying the relative roles of particular barriers to the amount of total reproductive isolation between populations or closely related species can provide important clues to the mechanisms of population divergence and speciation Phenotypic trait differences among populations are thought to reflect the interaction between the intensity of gene flow versus the strength of local selection and drift. READ MORE

  4. 2. Causes and consequences of niche differentiation between color morphs of pygmy grasshoppers

    Author : Einat Karpestam; Anders Forsman; Birgitta Tullberg; Linnéuniversitetet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; color polymorphism; visual predators; Tetrix subulata; differential habitat use; niche; thermoregulation; feeding preferences; stable isotopes; Evolutionary Biology; Evolutionsbiologi;

    Abstract : In this thesis, I used the color polymorphic pygmy grasshopper, Tetrix subulata, as a model system in order to investigate the degree of niche differentiation between alternative color morphs that are present within a single population. First, I hypothesized that individuals belonging to different color morphs differ in their innate food preference due to somewhat dissimilar physiology, and in their actual food consumption due in part to differential habitat use. READ MORE

  5. 3. Systematics, phylogeography and multiple origins of morphs in two species complexes belonging to Cistaceae, Helianthemum oelandicum and H. nummularium

    Author : Eman Soubani; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; introgression; parallel evolution; postglacial migration; genetic polymorphism; Pleistocene; morphometry; H. nummularium; Helianthemum oelandicum; cpDNA;

    Abstract : The Helianthemum oelandicum complex shows considerable morphological variation across its geographic distribution in Europe and western Asia. By combining four primer pairs and four restriction enzymes I identified nine cpDNA haplotypes with distinct geographical distributions. READ MORE

  6. 4. Ontogeny and Population Biology of a Sex-Limited Colour Polymorphism

    Author : Jessica Abbott; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; embryologi; ontogeni; animal morphology; embryology; Utvecklingsbiologi; Damselflies; Colour polymorphism; Development; Frequency-dependence; Morphology; growth animal ; ontogeny; Animal anatomy; Development biology; Djurs anatomi och morfologi; Population divergence; Animal ecology; Djurekologi;

    Abstract : This study has involved investigation of number of populations of the damselfly Ischnura elegans over several years, looking at frequency changes over time, morphological differences between the sexes and the morphs, differences in growth rate and development time, differences in fecundity between the morphs, and genetic differentiation between populations. I. READ MORE

  7. 5. The descent of damselflies and variation in relation to sex

    Author : Beatriz Willink Castro; Evolutionär ekologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; sexual conflict; development; diversification; pleiotropy; correlational selection; damselfly;

    Abstract : Sexual conflict over mating shapes the interactions between males and females in many animals and is also responsible for dramatic adaptations in both sexes. In some species of pond damselflies (Odonata:Coeangrionidae), sexual conflict maintains discrete female-limited colour morphs over multiple generations and within populations. READ MORE