Speciation in the common chaffinch

Since 2016, we have been studying the chaffinch (Fringilla coelebs) population on the island of La Palma, in the Canary Island archiphelago, Spain. We are interested in understanding how island species adapt to local conditions upon colonization from the mainland (or from other islands) and the ecological and genomic mechanisms involved in the evolutionary divergence that takes place, ultimately resulting in a different species.

In collaboration with Juan Carlos Illera (Oviedo University) and Guillermo Blanco (MNCN-CSIC) we have studied the diversification of chaffinch forms in Macaronesia (Azores, Madeira, Canaries) and Northern Africa, and using genomewide markers we have been able to recover the colonization history of the different island. We found that there was a single wave of colonization that went from the mainland to Azores, then Madeira, then the different Canary islands. In the process, subsequent colonizations led to a decrease in genetic diversity, so that populations in the Canary Islands have the lowest genetic diversity of all. We found that all forms are differentiated in phenotype and genotype, and in the Canary islands each island has a genetically distinct population, suggesting that gene flow among island is restricted. Based on our results w propose that the species be divided into 5, so that in addition to the common chaffinch (Fringilla coelebs), we would include the Magreb chaffinch (Fringilla spodiogenys), Azores chaffinch (Fringilla moreletti), Madeira chaffinch (Fringilla maderensis) and the Canarian chaffinch (Fringilla canariensis). For further details check out this article:

Recuerda, M., J. C. Illera, G. Blanco, R. Zardoya, B. Milá. 2021. Sequential colonization of oceanic archipelagos led to a species-level radiation in the common chaffinch complex (Aves: Fringilla coelebs). Molecular Phylogenetics and Evolution, In press.

We are also interested in the chaffinch population in La Palma (subspecies palmae), because in the absence of the blue chaffinches, Fringilla teydea and Fringilla polatzeki, which occupy pine forests in Tenerife and Gran Canaria, respectively, the common chaffinch of La Palma has colonized the extensive pine forests on the island. We noticed early on that the birds on the chaffinch’s original habitat (humid cloud forest, or laurisilva) and those in the pine forest, looked different. The latter looked much paler overall, with more white on their breasts and apparently larger bills. In the last several years we have been sampling all over La Palma to understand these differences and explore their genomic basis so we can shed light on the process of local adaptation. So far we have found striking genetic differentiation among localities, suggesting that dispersal is very low and gene flow highly constrained. We have generated a high-quality reference genome for the species and have obtained genome-wide sequences for several individuals in the different habitats, so we can detect the regions of the genome responsible for the phenotypic traits we find to be important in local adaptation.

Related Publications

Morinha, F.*, B. Milá*, J. A. Dávila, J. A. Fargallo, J. Potti, G. Blanco. 2020. The ghost of connections past: a role for mainland vicariance in the isolation of an insular population of the red-billed chough (Aves: Corvidae). Journal of Biogeography, 47(12): 2567-2583.

Benítez-López, A., L. Santini, J. Gallego-Zamorano, B. Milá, P. Walkden, M. A. J. Huijbregts, J. A. Tobias. 2021. The island rule explains consistent patterns of body size evolution across terrestrial vertebrates. Nature Ecology & Evolution, 5:768-786.

Recuerda, M., J. C. Illera, G. Blanco, R. Zardoya, B. Milá. 2021. Sequential colonization of oceanic archipelagos led to a species-level radiation in the common chaffinch complex (Aves: Fringilla coelebs). Molecular Phylogenetics and Evolution, In press.

Recuerda, M.*, J. Vizueta*, C. Cuevas-Caballé, G. Blanco, J. Rozas, B. Milá. 2021. Chromosome-level genome assembly of the common chaffinch (Aves: Fringilla coelebs): a valuable resource for evolutionary biology. Genome Biology and Evolution, 13(4):evab34.

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