The Changing Pace of Insular Life: 5000 Years of Microevolution in the Orkney Vole(Microtus Arvalis Orcadensis)

Research on the Orkney vole (Microtus arvalis orcadensis) reveals that human activity can significantly accelerate and complicate evolutionary patterns in island species. Introduced to the Orkney archipelago around 5000 years ago, these voles exhibited rapid morphological changes, such as molar gigantism, shortly after colonization, likely due to founder events and adaptation. A second major phenotypic shift occurred between the 4th and 12th centuries AD, coinciding with increased pastoral farming, competition from introduced species (mice and rats), and predation by foxes and cats. This challenges the traditional model of island evolution, which predicts initial rapid divergence followed by stasis, instead demonstrating a more complex trajectory driven by human influence.

Cucchi, T., Barnett, R., Martínková, N., Renaud, S., Renvoisé, E., Evin, A., Sheridan, A., Mainland, I., Wickham-Jones, C., Tougard, C., Quéré, J. P., Pascal, M., Pascal, M., Heckel, G., O’Higgins, P., Searle, J. B., & Dobney, K. M. (2014). THE CHANGING PACE OF INSULAR LIFE: 5000 YEARS OF MICROEVOLUTION IN THE ORKNEY VOLE(MICROTUS ARVALIS ORCADENSIS). Evolution, 68(10), 2804–2820. https://doi.org/10.1111/evo.12476