uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Cross-fostering reveals seasonal changes in the relative fitness of two competing species of flycatchers
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
Show others and affiliations
2004 (English)In: Biology Letters, Vol. 1, 68-71 p.Article in journal (Refereed) Published
Place, publisher, year, edition, pages
2004. Vol. 1, 68-71 p.
URN: urn:nbn:se:uu:diva-95233OAI: oai:DiVA.org:uu-95233DiVA: diva2:169366
Available from: 2006-11-24 Created: 2006-11-24 Last updated: 2009-03-31Bibliographically approved
In thesis
1. Natural and Sexual Selection in a Natural Hybrid Zone of Ficedula Flycatchers
Open this publication in new window or tab >>Natural and Sexual Selection in a Natural Hybrid Zone of Ficedula Flycatchers
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Speciation can be viewed as the formation of reproductive barriers between different populations. This thesis investigates patterns of natural and sexual selection shaping reproductive barriers between two hybridizing flycatchers (i.e. collared – and pied flycatchers). Behaviorally driven sexual isolation depends on both the availability of conspecific mates and on discrimination ability of individuals. My results demonstrate that these two factors may also interact. Discrimination abilities may change in response to the relative frequency of two interbreeding species. The underlying reason appears to be that male pied flycatchers have a song that incorporates more elements of the song characteristics of male collared flycatchers into their own song repertoires when occurring in areas inhabited predominantly by collared flycatchers. I investigated selection pressures acting on hybrids. In migratory species, hybrid fitness might be reduced as a consequence of intermediate suboptimal migration routes (extrinsic post zygotic isolation). Comparison of stable isotope signatures of revealed that parental species have separate wintering grounds, but hybrids appear to winter at the same location as pied flycatchers. A possible dominance effect in the inheritance of migration direction may hence reduce this potential cost. This interpretation is supported by the absence of a reduction in juvenile to adult survival of hybrids. By further comparing male hybrid fitness to that of the parental species, using lifehistory data, I demonstrate that hybrid males experience a moderate reduction in fitness (mainly through a sexually selected disadvantage). Sexual selection acting on male hybrids can play a major role in the speciation process because when the same characters affect assortative mating as well as hybrid fitness, reinforcement of reproductive barriers becomes more likely. Even when reproductive isolation is completed- the fate of newly formed species may be uncertain since they may strongly compete for ecological space. Long-term persistence of ecologically similar, species requires that there are spatial or temporal variation in their relative fitness. The growth of nestling pied flycatchers is less affected by harsh environmental conditions. We suggest that a regional co-existence of the two flycatcher species is due to a lifehistory trade-off between interference competitive ability and robustness to a harsh conditions. Overall, the studies in this thesis reveal the complexity of the interactions between mate choice and competition in shaping sexual signals. Furthermore, it suggests that natural selection is moderate on hybrid males and that sexual selection may have strong implications for the maintenance of species integrity.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. 32 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 248
Biology, postzygotic isolation, prezygotic isolation, asymmetrical isolation, sexual signals, hybrid fitness, co-existence, Biologi
urn:nbn:se:uu:diva-7372 (URN)91-554-6744-X (ISBN)
Public defence
2006-12-16, Zootissalen, Zoologen, Villavägen 9, 75236, Uppsala, 13:00 (English)
Available from: 2006-11-24 Created: 2006-11-24 Last updated: 2011-02-16Bibliographically approved

Open Access in DiVA

No full text

By organisation
Animal Ecology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 168 hits
ReferencesLink to record
Permanent link

Direct link