Locomotor activity of representative wild type flies showing arrhythmic behaviour before death. Actogram during a period of LD 12:12 followed by a free running rhythms in DD (the white area marks the light phase, the grey shaded area marks the dark phases). Left y-axis indicates the age of each fly and right y-axis indicates the days before death. Dagger is used as label of death. Well-entrained flies of different ages (A) died at 66-day-old, showing a 2-day arrhythmic activity with a FFT value of 0.0001 before death (0.049 in LD and 0.011 in DD), (B) died at 56-day-old, showing a 4-day arrhythmic activity with a FFT value of 0.008 before death (0.021 in LD and 0.017 in DD), and (C) died at 31-day-old, showing a 3-day arrhythmic activity with a FFT value of 0.0006 before death (0.046 in LD and 0.099 in DD).