. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 8 9 10 11 12 13 14 15 16 17 18 3°C 8°C. 8 9 10 11 12 13 14 15 16 17 18 Daylength (h) Date Feb 1 10 21 Mar 6 18 29 Apr 10 20 May 5 20 Daylight (h) Temp (°C) 10 11 333 12 468 13 10 11 14 13 18 Figure 3. Three patterns of springtime diapause responses under varying combinations of photoperiod and temperature. (A) Strict critical-photoperiod response with thermal effect. (B) Critical-photoperiod response with a graded transition from 100% non-diapause to 100% diapause covering a photoperiod range of abou
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 8 9 10 11 12 13 14 15 16 17 18 3°C 8°C. 8 9 10 11 12 13 14 15 16 17 18 Daylength (h) Date Feb 1 10 21 Mar 6 18 29 Apr 10 20 May 5 20 Daylight (h) Temp (°C) 10 11 333 12 468 13 10 11 14 13 18 Figure 3. Three patterns of springtime diapause responses under varying combinations of photoperiod and temperature. (A) Strict critical-photoperiod response with thermal effect. (B) Critical-photoperiod response with a graded transition from 100% non-diapause to 100% diapause covering a photoperiod range of about 2 h and a temperature delay of h per 1°C. as is typical of many insects. (C) Gradual transition from 100%- non-diapause to 100%- diapause with lengthening daylength as seen for D sungiiiiu-iis (Fig. 2), but with the added assumption that all animals produce diapausing eggs at long photoperiods independent of temperature. (D) Same graph as in C, but with response line relabeled to show the effect of selection for later diapause. (E) Springtime pattern of increasing photoperiod and temperature typical of Bullhead Pond, Rhode Island (see Table I). These values are used in A. B. and C to illustrate projected diapause phenologies. In each case the mean switch to diapause occurs at h daylength and 7°C. Hairston and Dillon. 1990). What features of the photo- period and temperature responses of the Little Bullhead Pond populations were altered by selection to produce the change in diapause phenology? For diapause timing to be heritable, the hypothetical temperature-specific photoperiod-response lines in Figures 2 and 3C must vary depending upon genotype. That is, for some genotypes the lines lie above the population mean, and for others the lines lie below the mean. Directional selection for later diapause would simply move the population mean re- sponse lines upward (as in Figure 3D). The effect is a joint one on both thermal and photoperiodic responses of the copepods
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
