The long-tailed finch, Poephila acuticauda provides a long-established example of sub-species divergence across the Top-End of Australia based on bill colour, with red-billed birds in the east and yellow-billed birds in the west. Based on studies across the whole species range in the field; over a decade of experimental breeding in the laboratory; and genomic data; we have identified a cryptic hybrid zone 350km to the west of that based on bill colour. In this location, there is a steep cline in the genetic divergence of both the Zchromosome and the mitochondrial genome, suggestive of strong selection. Our data indicate the presence of a large chromosomal inversion on the Z sex chromosome, supporting the idea that chromosomal inversions play a significant role in speciation processes. I will also present recent experimental data using cellular respirometry to support the idea that mito-nuclear incompatibilities can affect optimal mitochondrial function, and help to select against hybridisation and the maintenance of barriers between species.
Simon is a Professor in the School of Natural Sciences at Macquarie University, Sydney. He completed his PhD focused on sexual selection in the house sparrow in Terry Burke’s lab at the University of Leicester, UK, and then completed postdocs in Uppsala, Oxford and Imperial College, working on sexual selection and speciation in a number of European birds collared flycatchers before moving to Australia in 2004. His research program in Australia has focused on a variety of questions in evolutionary ecology, and particularly with his long-running study of the zebra finch. However, his work on speciation has focused primarily on the Gouldian and long-tailed finches, both of which he has studied in the laboratory and the field. You can read more about his research on his website: https://griffithecology.com