. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 266 RAYMOND G. STROSS 100 * 80 Q 8 60 cc 00 CD co 40 2 20 10 •+• i LEGEND: + = 1/20 ml • = 1/20ml-1/4 LIGHT *= 3/20 o= 5/20 - = 45°N - = 7I°N INTENSITY I 1 0. 4 8 12 16 HOURS OF LIGHT/24 HOURS 20 22 24 FIGURE 1. Reproductive shift of Daphnia middendorffiana in response to daylength and culture density. First and second-generation young born in constant light and transferred to photoperiod indicated. Photoperiod response of winter diapausing population of D. pulex at 45° N is shown for comparison. All experiments at 12° C. St
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 266 RAYMOND G. STROSS 100 * 80 Q 8 60 cc 00 CD co 40 2 20 10 •+• i LEGEND: + = 1/20 ml • = 1/20ml-1/4 LIGHT *= 3/20 o= 5/20 - = 45°N - = 7I°N INTENSITY I 1 0. 4 8 12 16 HOURS OF LIGHT/24 HOURS 20 22 24 FIGURE 1. Reproductive shift of Daphnia middendorffiana in response to daylength and culture density. First and second-generation young born in constant light and transferred to photoperiod indicated. Photoperiod response of winter diapausing population of D. pulex at 45° N is shown for comparison. All experiments at 12° C. Starvation may be discounted as a stimulus associated with culture density. All densities received the same bi-daily ration of food, and this is reflected in the number of young in broods of non-diapausing embryos. At 12° mean brood size for the test interval, which includes the first four or five broods of the adult re- productive period was young brood at a density of 1/20 ml and and young at densities of 3 and 5/20 ml, respectively, in constant light. Overwintering generation Daylength and density may also control the reproductive shift in the overwin- tering generation. These stimuli are effective, however, only after the adults have produced one or two broods of non-diapausing embryos (or young) and under conditions which are inductive for first and second generation adults. Young which had spent most of their prenatal development in constant light, either in the field or in the laboratory were subjected to four photoperiods at densities of. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redf
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
