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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Physiological trade-offs in reproduction and condition dependence of a secondary sexual trait

Andersson, Måns S. January 2001 (has links)
<p>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. Early breeding and high fitness were found to be associated with high levels of glycosylated haemoglobin possibly governed by migratory exertion and infectious disease. In order to test if immune function is expressed in secondary sexual traits and how it is traded off against reproductive effort a series of experiments were performed, in which birds were challenged with an antigen, via a vaccine containing neutralised paramyxovirus. The forehead patch of the male collared flycatcher serves as a badge of status and is under sexual selection. Good condition, as reflected in strong immune response and low levels of blood parasites was found to be associated with bigger patch size. Patch size was also found to vary in size within the same breeding season in a pattern predictable from immune response data. Immune response, in itself, was found to be costly in terms of reduced survival, confirming that trade-offs involving suppression of immune response may increase fitness. Mating effort was found to be traded off against immune function and moult. Experimental brood size manipulations revealed a trade-off females between number of offspring and immune function. Thus I suggest a set of parameters useful for condition estimation. I also show that immune response is costly and, second, that pathogen resistance probably plays an important role in the shaping of secondary sexual traits and life-history decisions.</p>
2

Physiological trade-offs in reproduction and condition dependence of a secondary sexual trait

Andersson, Måns S. January 2001 (has links)
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. Early breeding and high fitness were found to be associated with high levels of glycosylated haemoglobin possibly governed by migratory exertion and infectious disease. In order to test if immune function is expressed in secondary sexual traits and how it is traded off against reproductive effort a series of experiments were performed, in which birds were challenged with an antigen, via a vaccine containing neutralised paramyxovirus. The forehead patch of the male collared flycatcher serves as a badge of status and is under sexual selection. Good condition, as reflected in strong immune response and low levels of blood parasites was found to be associated with bigger patch size. Patch size was also found to vary in size within the same breeding season in a pattern predictable from immune response data. Immune response, in itself, was found to be costly in terms of reduced survival, confirming that trade-offs involving suppression of immune response may increase fitness. Mating effort was found to be traded off against immune function and moult. Experimental brood size manipulations revealed a trade-off females between number of offspring and immune function. Thus I suggest a set of parameters useful for condition estimation. I also show that immune response is costly and, second, that pathogen resistance probably plays an important role in the shaping of secondary sexual traits and life-history decisions.

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