image: The medium ground finch Geospiza fortis on Daphne Major Island view more
Credit: Image courtesy of Peter R. Grant.
A study finds two pathways of species generation and diversification among Darwin's finches. Darwin's finches on the Galápagos Islands have exemplified the mechanisms of species divergence since the genesis of evolutionary theory. Various species of finches have diverged from a common ancestor and display adaptations in size and beak shape, although the processes underlying the genetic isolation of new species are unclear. Peter R. Grant and B. Rosemary Grant tracked finches on the island of Daphne Major between 1976 and 2012, recording the body and beak dimensions of individuals and identifying parent-offspring relationships. The authors found that two species of finches selected mates with body and beak sizes, as well as songs, similar to those of their parents, particularly those of the father. Such imprinting ensures that successive generations breed with birds of a similar lineage, thereby avoiding interbreeding with other species. The authors note that hybridization with other species occasionally happens, when species express similar adaptive traits, and such hybridization can itself drive speciation. According to the authors, conservation of diverse environmental conditions, such as those that lead to species radiation, including geographic heterogeneity, is essential to ensure future species diversification.
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Article #18-13662: "Role of sexual imprinting in assortative mating and premating isolation in Darwin's finches," by Peter R. Grant and B. Rosemary Grant.
MEDIA CONTACT: Peter R. Grant, Princeton University, NJ; tel: 609-258-5156; e-mail: prgrant@princeton.edu
Journal
Proceedings of the National Academy of Sciences