Ryan Garrick

For his PhD, Ryan is researching the phylogeography of 'giant' Collembola (primitive insects - springtails - only these ones have no 'spring'!) and Symphyla (myriapods). These relatively unknown creatures have important roles in decomposing wood (the saproxylic habitat) although we know relatively little about them.

In recognition of his excellent Honours year and numerous undergraduate awards, Ryan won the La Trobe University David Myers PhD Scholarship. In 2003-5, he was awarded research grants by the ANZ Trustees, Holsworth Wildlife Research Fund, and was sponsored to attend the International Congress of Genetics (Genetics Society of Australia) and 34th Australian Entomological Society/ 6th Invertebrate Biodiversity & Conservation Conference (Department of the Environment and Heritage – ABRS).

Ryan's work is based at our main comparative phylogeography study site at Tallaganda State Forest / National Park, NSW.

The results for the first species analysed are very striking. The 'smooth' springtail shows very strong differences among regions within the forest, on the scale of a few Km. The network below left shows the evolutionary relationships among different mitochondrial DNA sequences that can be found in smooth springtails in the forest. The frequencies of these different types are represented as pie charts on the map to the right.

The different areas of the forest are thus thus home to different genetic types. While we are yet to see whether these different types can be interpreted as separate species, they are certainly as genetically different as some other organisms that do not naturally interbreed. Of particular interest is the area containing the yellow and green DNA type and their sequences. This area is thought to represent a refuge (shelter) during the last glaciation, and indeed harbours an important and diverse radiation of smooth springtails. A paper on this work is close to submission for Molecular Ecology.