Sökning: "Reproductive Effort"

Visar resultat 1 - 5 av 36 avhandlingar innehållade orden Reproductive Effort.

1. 1. Costs and Tactics in the Evolution of Reproductive Effort

   Författare :Ingemar Jönsson; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; capital breeding; Falco tinnunculus; body mass; DEE; reproductive effort; reproductive costs; income breeding; Animal ecology; Djurekologi;

   Sammanfattning : This study focuses on various aspects of costs of reproduction and the evolution of energetic breeding tactics. It emphasizes the distinction between demographic costs of reproduction expressed already before current offspring have reached independence (prebreeding costs), and costs expressed only after offspring independence (postbreeding costs). LÄS MER

3. 2. Costs, benefits and constraints in the evolution of avian reproductive tactics: a study on the blue tit

   Författare :Erik Svensson; Evolutionär ekologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; reproductive timing; selection analysis; natural selection; mate quality; nestlings; sex ratio; DNA-content; flow cytometry; ELISA; BMR; energetics; immunocompetence; immune system; sexual conflict; nestling mortality; thermoregulation; moult; reproductive costs; reproductive effort; Parus caeruleus; blue tit; birds; juvenile survival; laying date; food supply; Animal ecology; Djurekologi;

   Sammanfattning : In this study I have investigated the various factors influencing reproductive tactics among breeding blue tits (Parus caeruleus). The study was carried out in a nestbox-breeding population of marked individuals at the Revinge Area, outside Lund, southern Sweden. LÄS MER

4. 3. Pollinators, Enemies, Drought, and the Evolution of Reproductive Traits in Primula farinosa

   Författare :Per Toräng; Jon Ågren; Johan Ehrlén; Rebecca Irwin; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Ecology; Alternative reproductive strategies; climate change; facilitation; floral display; flowering phenology; frequency-dependent selection; genetic diversity; life-history strategies; local adaptation; pollination; predation; Primula farinosa; reproductive effort; soil disturbance; stochastic growth rate; Ekologi;

   Sammanfattning : In this thesis, I combined comparative and experimental approaches to examine selection on reproductive traits and population differentiation in the insect-pollinated, self-incompatible, perennial herb Primula farinosa. More specifically, I (1) determined whether the effects of floral display and interactions with pollinators and seed predators, and plant reproductive success were frequency-dependent and affected by surrounding vegetation context, (2) examined the consequences of intermittent drought years on population dynamics using numerical simulations based on demographic data collected over seven years, (3) analyzed among-population differentiation in flowering phenology and reproductive allocation, and its relationship to soil-depth at the site of origin. LÄS MER

5. 4. Age, Longevity and Life-History Trade-Offs in the Collared Flycatcher (Ficedula albicollis)

   Författare :Joanna Sendecka; Lars Gustafsson; Anna Qvarnström; Pat Monaghan; Uppsala universitet; []
   Nyckelord :Ecology; age; collared flycatcher; Ficedula albicollis; long-term study; senescence; longevity; reproductive success; selection; individual quality; breeding experience; reproductive effort optimization; terminal investment; life-history trade-offs; reproductive costs; Ekologi;

   Sammanfattning : Age is often a neglected factor in ecological studies. However, age-related changes in reproduction and survival of organisms may strongly influence population dynamics. LÄS MER

7. 5. Reproductive allocation and costs of reproduction in subarctic herbs : A resource-based perspective

   Författare :Åsa M. Hemborg; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Altitudinal gradient; Plant size; Predispersal seed predation; Reproductive effort; Resourcedynamics; Seasonal variation; Sexual dimorphism; Somatic costs; Unisexual plants; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

   Sammanfattning : The influence of internal and external factors on two major plant life history components, i.e., reproductive allocation and costs of reproduction, was examined for nine perennial herbs in subarctic Swedish Lapland. In one study, comparisons were made between Sweden and the French Alps. LÄS MER