Wild clocks

Most organisms organize their activities through circadian (i.e. day/night) clocks, which in turn are entrained to environmental information such as light. Circadian clocks allow organisms to anticipate daily events and are ubiquitous in nature. They “tick” at different rates in different individuals, thus showing variation in their properties, such as period length, which is highly heritable. But the evolution of clocks is only possible if this variation is also associated with fitness differences. Currently, however, almost nothing is known about how natural selection operates on daily timing mechanisms.

This project aims to fill some gaps in our knowledge about the microevolution of biological clocks by focusing on the latitudinal adaptation of the great tit (Parus major). This songbird is one of the most well-studied wild species and allows a range of experiments in the field and in captivity. Also, given the wide geographical distribution of the great tit, we can also study local adaptation by comparing populations from various latitudes. The highly contrasting light/dark environments between Arctic and southern populations is expected to select different clock properties.

The main goals of the project will be:

1)      Characterize populational differences in clock properties, focusing on latitudinal differences.

2)      Investigate the genetic basis of such differences through a “common garden” approach.

3)      Develop methods that allow linking circadian clock properties and fitness in wild animals and apply them to the studied populations

External collaborators: Marcel E. Visser and Kees van Oers (NIOO, Netherlands Institute of Ecology)


Barbara Mizumo Tomotani (Principal investigator)

Financial/grant information:


NWO (Dutch Research Council)