Time traveling through hybrid zones: A natural laboratory for studying speciation in birds using museum specimens
- Beschreibung
How are species formed and how can they persist in response to fast environmental change? Although the traits causing lineage split through time (species formation) are difficult to infer from fully reproductively isolated “good species”, those traits can be directly observed in closely related species that often hybridize; i.e. “bad species”.
Here, we use the moving hybrid zone in Iran between two songbird species — the black-headed and red-headed buntings — as a “natural laboratory to study speciation” and to identify the traits that are under selection, and thus underlying species formation. Males differ in multiple plumage coloration patterns that are hypothesized to be under sexual selection. Males and females also differ in several morphometric traits (for example, wing length, beak characteristics) that are hypothesized to be either selectively neutral or under environmental selection (Figure 1 - see supplementary pdf).
If sexual selection is a strong motor of species formation, we expect that traits related to color pattern show a steeper transition in a hybrid zone compared to morphometric traits. A previous bachelor's thesis based on modern sampling found strong support for this hypothesis (Figure 2).
Strong aridification of Iran has led to a movement of the hybrid zone towards Europe. In this project, we will use historical samples collected in an expedition to the center of the hybrid zone 50 years ago, as “time machine” to understand how traits under sexual and environmental selection have responded to environmental change.
We expect the transition zones of sexually and environmentally selected traits to have shifted westwards at different rates, depending on the strength of sexual and natural selection. Specifically, if sexual selection remains a stronger force maintaining species boundaries, plumage coloration should retain a steep transition despite a geographic shift. Conversely, morphometric traits may show a more gradual change that tracks changes in the environment.
All workflows for assessing spatial variation on traits are already established in the lab. This project will involve using those methods in historical specimens, and comparing them to data from modern specimens. Results from this project may motivate a future Bachelor thesis.
- Projektzeitraum
- Wintersemester 2025/2026
- Bewerbungszeitraum
- 13. bis 27.10.2025
- Durchführung
- semesterbegleitend
- Details zu Projektzeitraum und Durchführung
Project work includes:
- Identify high-accuracy locations for specimens stemming from historical expeditions to the hybrid zone
- Assess colouration patterns using photographs from samples collected 50 years ago
- Establish clines (Figure 2) for color pattern and morphometric traits in historical samples.
- Compare transitions in traits between historical and modern data to test how sexual and environmental selection have responded to climate change.
- Studienfach
-
Biologie
Biologie - Lehramt
Landscape Ecology - Betreuende
- Louis Hausner
- Institut
- State Museum of Natural History Stuttgart (Biodiversitätsmonitoring)
- Sprache
- deutsch/englisch
- Teilnehmendenanzahl
- min. 1, max. 1
- Arbeitsaufwand
-
ca. 180 Stunden pro Teilnehmende:r
| 6
ECTS-Punkte
Arbeitsaufwand (Stunden und ggf. ECTS) sind ungefähre Angaben. Die tatsächlich vergebenen ECTS-Punkte ergeben sich aus der tatsächlich geleisteten Arbeit.
- Für dieses Projekt ist kein Motivationsschreiben des Studierenden erforderlich
- Projektart
- empirisch
- Lernziele
-
Die Teilnehmende lernen in diesem Projekt:
In this project, participants will:
- Get familiar with museum collections and the importance of hybrid zones as natural laboratories to study speciation.
- Learn more about the different types of selection contributing to speciation.
- Get familiar with how to analyze colouration and morphometric traits.
- Gain elementary knowledge of working with R to run cline analyses to estimate the strength of selection.
- Engage in diverse scientific discussions on hybridization and speciation across taxa.
- Anmerkungen für Studierende
Supervisors
Dr. Niloofar Alaei Kakhki, Prof. Dr. Ricardo J., Pereira, Louis Hausner
Contact
louis.hausner@smns-bw.de
niloofar.alaei@smns-bw.de- Dokument
- Schlagworte
- Natural History, Hybridisation, Speciation, Moving hybrid zone, Sexual Selection, Tiere, Natural Selection, Datenanalyse, Klimawandel