Sökning: "diet selection"
Visar resultat 1 - 5 av 40 avhandlingar innehållade orden diet selection.
1. The development of resource polymorphism – Effects of diet, predation risk and population dynamical feedbacks
Sammanfattning : This thesis deals with the evolution of individuals within a species adapted to utilize specific resources, i.e. resource polymorphism. Although a well-known phenomenon, the understanding of the mechanisms behind is not complete. LÄS MER
2. Costs of foraging in a dry tropical environment
Sammanfattning : This study evaluates the costs associated with foraging for birds in a savannah woodland area in central Nigeria. Specifically, it looks at the following questions: 1) how does seasonal variability in food and water availability affect the value of resources to birds in dry environments? 2) Does proximity to water affect foraging decisions? What implication will this have in the management of savannah birds? 3) Are tropical birds mostly affected by metabolic or predation costs? 4) What factors affect diet selection in birds and how? 5) How are birds adapted to hot dry environments? I carried out experiments in the field and in an aviary and provided artificial food patches, consisting of feeding trays with seeds mixed in sand or pebbles (in the aviary study). LÄS MER
3. Island biogeography and population divergence in the Skyros wall lizard
Sammanfattning : Islands are cradles for new biodiversity and provide natural laboratories for the study of population divergence. In my thesis, I investigated the role of different evolutionary processes in the population divergence in the Skyros wall lizard (Podarcis gaigeae), a species where islet populations have strongly diverged morphologies. LÄS MER
4. Overweight and obesity in the young and old: Prevalence, prevention and eating behavior
Sammanfattning : ABSTRACT Background: During the last 25 years the prevalence of overweight and obe-sity has increased dramatically, both in developed and developing countries. The World Health Organization is declaring it an epidemic. In Sweden the increase was almost 50% between 1980 and 2005. The largest increases oc-curred in the 16-24-year age group. LÄS MER
5. Conservation, personality and ecology of the European mink (Mustela lutreola)
Sammanfattning : Loss of biodiversity is a growing problem and hence conservation of species is becoming increasingly important. In this dissertation conservation issues related to the critically endangered European mink (Mustela lutreola) are examined in situ (in the wild) and ex situ (in captivity) on both an individual and community level. LÄS MER
