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Adjustment of resting metabolic rate by pied flycatchers to the environment promotes regional coexistence with sister species
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.ORCID iD: 0000-0002-0706-458X
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology. University of Helsinki.ORCID iD: 0000-0003-2861-9721
University of Helsinki.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.ORCID iD: 0000-0002-1178-4053
(English)Article in journal (Refereed) Submitted
Abstract [en]

Differences in life history strategies of closely related species can result in variation in relative fitness across heterogeneous environments and promote coexistence. However, physiological mechanisms mediating such variation in relative fitness have not been identified. Resting metabolic rate (RMR) is tightly associated with life-history strategies and could therefore moderate differences in fitness responses to fluctuations in local environments, particularly when species have evolved to different climatic niches in allopatry. We explore whether differences in RMR match changes in relative fitness between collared (Ficedula albicollis) and pied flycatchers (Ficedula hypoleuca) across environmental conditions experienced in a recent hybrid zone. We found a negative correlation between nestling RMR and temperatures experienced during growth in pied flycatchers, which was absent in collared flycatchers. This implies that pied flycatchers are better adapted to the typical seasonal changes in temperature and food availability experienced at these northern breeding sites. There was sufficient additive genetic variance in RMR to respond to selection in both species that may either facilitate ecological character displacement or lead to a breakdown of coexistence. Generally, subtle differences in climate adaptation may play an important role to patterns of competition, coexistence or displacements between closely related species at recent secondary contact.

National Category
Natural Sciences Ecology
URN: urn:nbn:se:uu:diva-309966OAI: oai:DiVA.org:uu-309966DiVA: diva2:1053214
Available from: 2016-12-08 Created: 2016-12-08 Last updated: 2017-01-10Bibliographically approved
In thesis
1. Speciation and Metabolic rate: Insights from an avian hybrid zone
Open this publication in new window or tab >>Speciation and Metabolic rate: Insights from an avian hybrid zone
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The role of divergent climate adaptation in speciation has received surprisingly little scientific attention. My dissertation research focused on how resting metabolic rate (RMR) relates to the build up of prezygotic and postzygotic isolation in a natural Ficedula flycatcher hybrid zone. RMR is the amount of energy an organism needs to run its internal organs. Since RMR is related to life history traits and thermoregulation in other systems, it is likely to affect speciation processes at secondary contact. I found that adult collared flycatchers displace pied flycatchers into increasingly poor habitats (Paper I). Pied nestlings exhibit lower RMR in poor environments (Paper II), which may promote regional coexistence and habitat isolation by making it possible for pied flycatchers to escape competition from collared flycatchers and reduce the risk of hybridization by breeding in the poorer habitats. Further, I found that while collared flycatcher nestling RMR was not environmentally-dependent (Paper II, Paper III), those collared flycatcher nestlings that had a lower RMR in poor environments tended to have higher condition (Paper III). Further, RMR was genetically linked to a sexual ornament in collared males that has previously been shown to be beneficial in poor environments. Lastly, I found that by seven days old, nestlings increase their metabolic rate when listening to song, indicating that they are listening, and by 9 days they can discriminate between songs (Paper IV). Taken together, RMR could affect pre-zygotic isolation via correlations with life history strategies, song and sexual ornaments. RMR is also related to post zygotic isolation in Ficedula flycatchers. I found that flycatcher hybrids tended to have a higher RMR than the parental species (Paper V), and that there were many differentially expressed genes in energetically expensive organs in hybrids that were related to metabolic function (Paper VI). Thus, metabolic dysfunction, possibly caused by genetic incompatibilities, in Ficedula flycatcher hybrids could be a factor leading to infertility and postzygotic isolation between the parental species. Overall, I find that RMR could be a general physiological trait that affects both pre- and postzygotic isolation in hybridizing species at secondary contact, and ought to be more thoroughly considered in speciation research. 

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2017. 43 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1462
resting metabolic rate, life history, hybridization, speciation, reproductive isolation, Ficedula flycatcher
National Category
Ecology Evolutionary Biology Genetics
Research subject
Biology with specialization in Animal Ecology
urn:nbn:se:uu:diva-309969 (URN)978-91-554-9776-7 (ISBN)
Public defence
2017-02-10, Zootissalen, Villavägen 9, Uppsala, 10:00 (English)
Available from: 2017-01-19 Created: 2016-12-08 Last updated: 2017-01-19

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