Figure 4

Lunar emergence times of Clunio laboratory strains are adapted to the tidal regime at their place of origin. We define the event of moonlight stimulus perception as the day when a low tide falls between 11 p.m. and 1 a.m. during the moonlit quarters of the lunar cycle. For different places along the coast, this event occurs at different phases of the lunar cycle, depending on the local tidal regime (compare Figure 3). The interval (in days) from this event to the spring tides in the field is plotted on the X-axis for each population. The interval (in days) between onset of artificial moonlight and the emergence peak in the laboratory is plotted on the Y-axis for the same populations. Error bars are standard deviations. Squares mark emergence peaks that fall to full moon, circles mark emergence peaks that fall to new moon in the field. Correlation coefficient and p value of the correlation are given in the graph. Strain identities: 1 Vigo (West Spain). 2 Santander (North Spain). 3 St. Jean-de-Luz (Basque Coast, France). 4 Port-en-Bessin (Normandie, France). 5 Lulworth (English Channel, UK). 6 Studland (English Channel, UK). 7 Bembridge (Isle of Wight, UK). 8 Roscoff (Bretagne, France). 9 Concarneau (Bretagne, France). 10 Camaret-sur-Mer (Bretagne, France). 11 St. Briac-sur-Mer (Bretagne, France). Data from [3, 30, 53]. For strains 9 to 11 own unpublished data is given.