Abstract:
The moon affects not only the water- and land masses of the earth, but also its organisms. This is particularly true for organisms in the sea and at the coasts. Examples for tidal rhythms are the vertical migrations of the diatome Hantzschia virgata, the activity of the isopode Excirolana chiltoni and the water content in wood stems. Daily, monthly and annual depositions have been observed in fossils. A fourteen-day rhythm displays the Grunion fish Leuresthes tennis by spawning at the beach, the terrestrial crab Sesarma haematocheir in discharging its larvae into the water, and the eclosion of the one-hour-midge Clunio marinus at the time of spring tide. Monthly rhythms with periods of 28 days are exhibited by the antlion Myrmeleon formicarius in building its pit, and by swarming of the Palolo worm. Women menstruate in a rhythm of 26 to 30 days. The time of menstruation is, however, not correlated with the lunar cycle. Primates in South America ovulate and concept at the time of the full moon. As an experiment it is proposed to study the monthly rhythm of the antlion.