Ring Species!!

Another well studied example is the Greenish warblers in Asia around the Tibetan plateau, which appear to have developed gradients of behavioural reproductive isolation associated with differences in mating songs. I don't know of a treatment of them in book form but there are a number of relevant papers published. I don't think most of them are open acces but at least one, 'Speciation by Distance in a Ring Species'(Irwin et al., 2005), only requires registering with the Science website to read.What might be called the 'classical' example of a ring species is the populations of herring gull distributed around the arctic circle. However more detailed genetic research and further evaluation has led to what was once held up as a nice clean example of a ring species to turn instead into a more complex mix of species and subspecies, see 'The herring gull complex is not a ring species' (Liebers et al., 2004).TTFN,WK

A query for '"ring species" AND evolution' on pubmed only produces 15 results but some of those are putative ring species I hadn't come across before.These are the Trumpetfish complex (Bowen et al, 2001), a group of Australian parrots (Joseph et al., 2008) and the great tit (Kvist et al., 2003). In both the bird cases the story is similar to that of the herring gull where it may be a case of the formation of secondary contact zones of previously temporarily isolated groups rather than true examples of a ring species developing.TTFN,WK