Sökning: "Karl Gotthard"
Visar resultat 1 - 5 av 12 avhandlingar innehållade orden Karl Gotthard.
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Sammanfattning : Diapause decision is a classic example of a threshold switch mechanism with cascading effects on morphology, behaviour and life-history traits. This thesis addresses the downstream effects of the insect diapause switch, with the main focus on pathway-specific regulation of life-history traits, using the speckled wood butterfly (Pararge aegeria) as a study species. LÄS MER
Sammanfattning : Life history research deals with the scheme of resource partitioning to a wide spectra of processes and the trade-offs shaping these events. One of the most fundamental life history trade-offs is the one of at which age- and size an organism should start to reproduce; reaching a large size at maturity is often advantageous in terms of high adult survival and reproductive potential, while to attain a larger size the organisms must prolong juvenile development which is assumed costly in terms of mortality. LÄS MER
Sammanfattning : According to theory, genetic diversity can be maintained by environmental variation and the degree of genetic and phenotypic polymorphism may enhance the ability of populations to endure stress imposed by changing environments. In my thesis I used colour polymorphic pygmy grasshoppers (Tetrix subulata) as a model system to explore how environmental variation influenced genetic diversity. LÄS MER
5. Geographic variation in life cycles : Local adaptation and ecological genetics in a temperate butterfly
Sammanfattning : Conditions in nature change with the seasons, necessitating seasonal adaptations that synchronize the life cycles of organisms with their surroundings. Such regulatory adaptations must vary between populations to track local variation in climate and seasonality; this local adaptation is facilitated by locally specific seasonal cues, but may be hampered by gene flow and genetic history. LÄS MER