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From Evolution to Clockworks:Unravelling the molecular basis of circalunar clocks

Periodic Reporting for period 1 - EVOCLOCK (From Evolution to Clockworks:Unravelling the molecular basis of circalunar clocks)

Reporting period: 2019-01-01 to 2020-06-30

"Nature is structured in time by the recurring cycles of night and day, seasons, tides and lunar phases. Most organisms possess so-called ""biological clocks"" for anticipating these regular changes in their environment and for adjusting their behavior and body functions accordingly. The daily clock (""circadian clock"", 24 hours) is well understood at the molecular level. But the mechanisms of tidal clocks (12.4 hours), lunar clocks (29.5 days) and annual clocks (1 year) are still largely unknown.

In this project we aim to uncover molecular mechanisms underlying the lunar clock in the marine insect Clunio marinus. Clunio has timed its reproduction to the lowest low tides, which always occur around new moon and full moon. As the tides differ along the coastline, Clunio has adjusted its lunar clock accordingly. By comparing Clunio strains with differing lunar clocks, we can identify candidate lunar clock molecules. This endeavor cannot be undertaken in classical biological model organisms like fruit fly or mouse, because these do not possess a lunar clock. For Clunio, in turn, many of the molecular tools and resources that are available for model organisms, are still lacking. Hence, the objectives of this project are to (1) establish tools to experimentally manipulate Clunio at the molecular level, (2) get a global overview of how Clunio uses its gene repertoire over the lunar cycle, and (3) characterize Clunio's nervous systems and the receptors by which it perceives the tides and lunar phases. Finally, we will try and bring together all of these lines of research for identifying and describing some lunar clock molecules and mechanisms.

Studying the lunar clock means exploring uncharted territory. Therefore, this project is clearly basic research. In the long term, understanding the lunar clock of Clunio will give insights into insect development and maturation, which may also highlight new opportunities for insect pest control. Knowledge on the lunar clock may further aid marine aquaculture and thus contribute to securing sustainable food supplies for a growing world population. Controlled breeding of marine organisms is often difficult, and much of this may have to do with the lack of understanding of the complex and often lunar-regulated reproduction of marine organisms."
In the first project period we have worked on establishing various molecular protocols for experimental manipulation and visualization in Clunio. We obtained a comprehensive overview of Clunio's larval nervous system and we were able to highlight specific substructures through selective staining.
Our results provide novel insights into the biology of an organism that has been barely studied at the molecular level. They offer new experimental opportunities and therefore are important milestones in our undertaking to try and understand the lunar clock.
Clunio marinus. Wingless female (left) and male (right).