Ecological speciation in South Atlantic island finches.
Examples of sympatric speciation in nature are rare and hotly debated. We describe the parallel speciation of finches on two small islands in the Tristan da Cunha archipelago in the South Atlantic Ocean. Nesospiza buntings are a classic example of a simple adaptive radiation, with two species on each island: an abundant small-billed dietary generalist and a scarce large-billed specialist. Their morphological diversity closely matches the available spectrum of seed sizes, and genetic evidence suggests that they evolved independently on each island. Speciation is complete on the smaller island, where there is a single habitat with strongly bimodal seed size abundance, but is incomplete on the larger island, where a greater diversity of habitats has resulted in three lineages. Our study suggests that the buntings have undergone parallel ecological speciation.
Ryan
Peter G
PG
Percy Fitz Patrick Institute, Department of Science and Technology/National Research Foundation Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa. Peter.Ryan@uct.ac.za
Bloomer
Paulette
P
Moloney
Coleen L
CL
Grant
Tyron J
TJ
Delport
Wayne
W
D000220:Adaptation, Biological; D000818:Animals; D001266:Atlantic Islands; D001502:Beak / Q000033:anatomy & histology; D005075:Biological Evolution; D049628:Body Size; D004272:DNA, Mitochondrial / Q000032:analysis / Q000235:genetics; D017753:Ecosystem; D046369:Finches / Q000033:anatomy & histology / Q000235:genetics; D049810:Genetic Speciation; D005843:Geography; D018895:Microsatellite Repeats; D012639:Seeds; D012641:Selection, Genetic
D004272:DNA, Mitochondrial