CAnMove

Willow warblers (Phylloscopus trochilus) in Sweden belong to two different subspecies; one breeding in the south (Ph. t. trochilus) migrating to wintering areas in West Africa, while the other breed in the north  (Ph. t. acredula) migrating to wintering areas in Southeast Africa. In this project, we investigate the genetics behind the migration programs using willow warblers and a hybrid zone between the two subspecies as a model system for studies how selection in the wild may evolve different migration routes.

In hybrid zones, individuals with very different migratory programs may breed together and produce (hybrid) offspring expressing a migratory program different to either of their parents. Such hybrid zones offer unique possibilities to examine the interaction between genes and the environment, and their joint effect to individual fitness.
We use independent markers to assign hybrids and back-crosses, derived from AFLP (Amplified Fragment Length Polymorphism), large scale studies in the hybrid zone of genotypes and phenotypic migratory direction assessed by stable isotopes to answer questions on: What kind of selection is maintaining the migratory divide; assortative mating or ecological selection against hybrids? How do the hybrid zone breeding dynamics vary with time?
 
This project is financially supported by project grants from the Swedish Research council.