Research Paper Volume 15, Issue 2 pp 396—420

Figure 2. Constant darkness has no effect on feeding, locomotion, fecundity, or circadian function. Several aging-related behaviors were measured after 14 days (activity and fecundity) or 21 days (feeding and circadian measures) under LD or DD conditions. (A) Female dye labeled food consumption over 24 hours was not significantly different in dark reared flies as measured by dye excretion (n = 10 per treatment group of 15 flies each, P = 0.83). (B) Males reared and kept under dark conditions ate, as measured by dye excretion, significantly more than those under LD conditions (n = 10 per treatment group of 15 flies each, P = 0.003). (C) There was no significant difference in average daily activity as measured by beam breaks in the Trikinetics DAM system over 5 days (LD n = 22, DD n = 20; P = 0.245). (D) Number of eggs laid across 7 days was not significantly altered by a 14-day LD cycle when compared to flies reared in DD (n = 10 per treatment group of 5 females each; P = 0.572). (E, F) Circadian health was measured by exposing both male LD and DD pretreated flies to a two-day 12 h: 12 hr LD schedule then placing both under free running (DD) conditions to assess rhythmic strength and free running period. Neither rhythmic strength as measured by FFT amplitude (E) (LD n = 30, DD n = 28; P = 0.346) or free running period (F) as measured by chi-square periodogram (LD n = 27, DD n = 26; P = 0.257) showed an effect of prior light environment.