| dc.date.accessioned | 2018-10-24T09:27:31Z | |
| dc.date.available | 2018-10-24T09:27:31Z | |
| dc.date.issued | 2018 | |
| dc.identifier.uri | http://hdl.handle.net/10852/65270 | |
| dc.description.abstract | Despite the similar function of all sperm cells – to fertilise the egg – there is extraordinary diversity in sperm shape and length across taxa. This thesis aims to improve our understanding of how this diversity has evolved, and how sperm morphology affects the function of the sperm, using a well-known study system for sperm research, the songbirds.
The results from the thesis demonstrate that sperm head morphology in songbirds is variable within and among species; both in length and in several other dimensions including shape. The work shows that the distinctive helical morphology of songbird sperm is associated with an increase in swimming speed, but that the fitness benefit of having strongly helical sperm heads is associated with a cost of more fragile sperm. Finally, the fourth chapter finds indications that feeding habits might influence sperm quality in urban birds.
This thesis contributes to our understanding of both the evolution and function of sperm morphology in songbirds, which may even be relevant for other taxa with similar sperm morphology. | en_US |
| dc.language.iso | en | en_US |
| dc.relation.haspart | Paper I: H. N., Rekdal, S. L., Kleven, O., Laskemoen, T., Marthinsen, G., Johnsen, A., & Lifjeld, J. T. (2016). Weak geographical structure in sperm morphology across the range of two willow warbler Phylloscopus trochilus subspecies in Scandinavia. Journal of Avian Biology, 47(5): 731-741. DOI: 10.1111/jav.00981. The paper is not available in DUO due to publisher restrictions. The published version is available at: https://doi.org/10.1111/jav.00981 | |
| dc.relation.haspart | Paper II: Støstad, H. N., Johnsen, A. Lifjeld, J. T. & Rowe, M. (2018) Sperm head morphology is associated with sperm swimming speed: a comparative study of passerine bird sperm using electron microscopy. Evolution, 72(9): 1918-1932. DOI: 10.1111/evo.13555. The paper is not available in DUO due to publisher restrictions. The published version is available at: https://doi.org/10.1111/evo.13555 | |
| dc.relation.haspart | Paper III: Støstad, H. N., Johnsen, A., Rowe, M. & Lifjeld, J. T. Sperm head abnormalities are more frequent in songbirds with more helical sperm. Manuscript prepared for submission to Biology Letters. To be published. The paper is not available in DUO awaiting publishing. | |
| dc.relation.haspart | Paper IV: Støstad, H. N., Rowe, M. & Lifjeld, J. T. Sperm head abnormalities are associated with excessive omega-6 fatty acids in two finch species feeding on sunflower seeds. Manuscript. To be published. The paper is not available in DUO awaiting publishing. | |
| dc.relation.uri | https://doi.org/10.1111/jav.00981 | |
| dc.relation.uri | https://doi.org/10.1111/evo.13555 | |
| dc.title | The evolution and function of sperm head morphology in songbirds | en_US |
| dc.type | Doctoral thesis | en_US |
| dc.creator.author | Støstad, Hanna Nyborg | |
| dc.identifier.urn | URN:NBN:no-67799 | |
| dc.type.document | Doktoravhandling | en_US |
| dc.identifier.fulltext | Fulltext https://www.duo.uio.no/bitstream/handle/10852/65270/1/PhD-Stoestad-2018.pdf | |