Data from: Species collapse via hybridization in Darwin's tree finches
Data files
Oct 01, 2013 version files 127.12 KB
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Allele size data Floreana Tree Finches 2005 and 2010 Dryad.xlsx
72.02 KB
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Assortative Pairing and Genetic Population_Am Nat.xlsx
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Genetic Population and Morphology_Floreana Tree Finches 2005 and 2010_Am Nat.xlsx
27.78 KB
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Philornis Intensity and Genetic Population_Floreana Tree Finches_Am Nat.xlsx
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Abstract
Species hybridization can lead to fitness costs, species collapse, and novel evolutionary trajectories in changing environments. Hybridization is predicted to be more common when environmental conditions change rapidly. Here, we test patterns of hybridization in three sympatric tree finch species (small tree finch Camarhynchus parvulus, medium tree finch Camarhynchus pauper, and large tree finch: Camarhynchus psittacula) that are currently recognized on Floreana Island, Galápagos Archipelago. Genetic analysis of microsatellite data from contemporary samples showed two genetic populations and one hybrid cluster in both 2005 and 2010; hybrid individuals were derived from genetic population 1 (small morph) and genetic population 2 (large morph). Females of the large and rare species were more likely to pair with males of the small common species. Finch populations differed in morphology in 1852–1906 compared with 2005/2010. An unsupervised clustering method showed (a) support for three morphological clusters in the historical tree finch sample (1852–1906), which is consistent with current species recognition; (b) support for two or three morphological clusters in 2005 with some (19%) hybridization; and (c) support for just two morphological clusters in 2010 with frequent (41%) hybridization. We discuss these findings in relation to species demarcations of Camarhynchus tree finches on Floreana Island.