Sökning: "cost of reproduction"
Visar resultat 1 - 5 av 47 avhandlingar innehållade orden cost of reproduction.
Sammanfattning : This thesis examines parental condition, how it is traded off against reproduction and how it is displayed in a secondary sexual trait. The studies were performed on nest-box breeding collared flycatchers Ficedula albicollis on the island of Gotland, in the Baltic Sea. LÄS MER
Sammanfattning : Ageing reduces fitness, but how ageing evolves is still unclear. Evolutionary theory of ageing hinges on the fundamental principal that the force of natural selection declines with age. LÄS MER
3. On starlings and farming: population decline, foraging strategies, cost of reproduction and breeding success
Sammanfattning : The European Starling Sturnus vulgaris as many other farmland bird species has been declining during the last decades. The cause of these declines is generally believed to be changes with in agricultural methods affecting breeding and survival of birds. LÄS MER
Sammanfattning : For the majority of the estimated 70,000 industrial chemical substances available on the European market today there is not enough information to enable a reasonably complete assessment of the risks that they might pose to man and the environment. Any strategy for the generation of additional data for these substances should aim at making testing as efficient as possible taking into account environmental and health protection, time, monetary cost and animal welfare. LÄS MER
Sammanfattning : Parasites are ubiquitous and can cause significant fitness reductions to their hosts. Therefore, selection for the evolution of host resistance should be strong. However, resistance may be costly and should be traded-off against other fitness related traits. LÄS MER