Elements of ecology (1954) Elements of ecology elementsofecolog00clar Year: 1954 220 Light Sept. Oct. Nov. Dec. Jan. Feb. Fig. Average daily number of conjugants of the ciliate Conchophtliirius la7nellidens on the gills of the fresh-water mussel Lamellidens niarginalis. Dates of new moon (top) and of peak numbers are shown. (Ray and Chakraverty, 1934, Nature.) Most of the organisms exhibiting lunar periodicities are marine and hence may be affected by the ampHtude of the tide which is greatest at times of new moon and full moon (spring tides) and smallest at the times of the quarter
Elements of ecology (1954) Elements of ecology elementsofecolog00clar Year: 1954 220 Light Sept. Oct. Nov. Dec. Jan. Feb. Fig. Average daily number of conjugants of the ciliate Conchophtliirius la7nellidens on the gills of the fresh-water mussel Lamellidens niarginalis. Dates of new moon (top) and of peak numbers are shown. (Ray and Chakraverty, 1934, Nature.) Most of the organisms exhibiting lunar periodicities are marine and hence may be affected by the ampHtude of the tide which is greatest at times of new moon and full moon (spring tides) and smallest at the times of the quarter moon (neap tides). For organisms living within the influence of the tides it is obviously difficult to determine how much of the effect may be due to moonlight itself and how much to the action of the tidal cycle. The marine alga, Dictyota, for ex- ample, produces its gametes at the time of the full-moon spring tide. The spawning of a number of marine polychaete worms shows various time correlations. The palolo worm inhabiting the waters of the South Pacific islands comes to the surface in great numbers on the last quarter of the moon during October and November, producing a luminescence and discharging eggs and sperm into the water. The natives know of the occurrence of this swarming of the palolo worm and take advantage of the opportunity to scoop up large quantities of these animals for food. The worms swim about in small circles in dense masses, giving the sea an appearance of spaghetti soup. The natives gather the worms in crude baskets and celebrate the occasion with religious rites and feasts. The Bermuda fireworm puts on a similar display of fireworks in the shallow water early in the evening at the time of full moon. The reaction appears to be set off by the drop in light intensity following sunset (Huntsman, 1948). Professor E. L. Mark, who was for years
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