Figure 1.

Day-night entrainment of locomotor activity by LD strobe and SPP. Averaged double-plotted locomotor activities of adult Drosophila for 5 d of entrainment by various light protocols followed by 3 d of DD. A, All flies are entrained to $\ge$3 d of 12 h:12 h LD before exposure to control standard LD (A, first row), 15 min SPP (A, middle row; yellow bars indicate 15 min of light exposure at caps of each 12-h day), or LD strobe (A, lower row; orange shade indicates 15 min of light followed by 45 min of dark for every hour of the 12-h day). Yellow or orange shade indicates windows of light exposure, black indicates lights off. B, Behavior actograms for three fly genotypes (W1118[5905], upper row; XLG-PER-Luc, middle row, and ptim-TIM-Luc, lower row) in three different entrainment schedules (standard LD, left column; 15 min SPP, middle column; LD strobe, right column). All entrainment schedules involve 5 d of respective light/dark regimes (yellow or orange shade/gray shade), followed by 3+ d of DD (gray shade). See Table 1 for number of flies used.