International Research Fellow Award: The Role of Migration in Speciation: a Study of Two Ring Species

Irwin, Darren E, La Jolla CA

Investigators

Abstract

0076212 Irwin The International Research Fellow Awards Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will provide Dr. Darren E. Irwin with support for twenty-four months to work with Dr. Staffan Bensch at Lund University in Sweden. The splitting of a single species into two, or speciation, takes a long time to occur and is thus difficult to observe directly. A rare opportunity to study speciation is provided by a ring species, in which a long chain or interbreeding populations encircle a geographic barrier; the terminal populations in the chain do not interbreed where they come together. For two ring species - the Willow Warbler encircling the Baltic Sea and the Greenish Warbler encircling central Asia - the principal investigator will use geographical variation around the ring to reconstruct how two species evolved from one. He will work with Dr. Bensch at Lund to focus on four questions: 1) In the contact zone between two forms of the Willow Warbler in central Sweden, are there differences in songs between the forms and are the differences used in mate choice? 2) How do migration patterns vary around the Greenish Warbler ring? 3) Is there gradual variation in Willow Warbler populations around the Baltic, thereby connecting forms in southern and northern Sweden? 4) What is the migratory behavior of hybrids in central Sweden? The answers will clarify the role of behavioral traits and selection against hybrids in speciation. Dr. Bensch uses novel techniques to study migration and to measure genetic differences between populations. Lund University has excellent facilities for studying both migration and genetic variation. ***