(A–C) Larvae were raised in LD and tested in DD. aanat2−/− larvae, but not sibling controls, lack circadian sleep oscillations. Black and hatched boxes represent subjective night and day, respectively. There is no significant difference in amount of sleep for aanat2−/− larvae during each subjective day (B) and night (C) (p>0.22 by Tukey’s test). (D–G) Larvae were treated with vehicle or 50 μM NECA on day 6. On night 6, vehicle-treated aanat2−/− larvae are more active (D,F) and sleep less (E,G) than vehicle-treated aanat2+/− larvae. In contrast, NECA-treated aanat2−/− larvae exhibit the same amount of activity (D,F) and sleep (E,G) as NECA-treated aanat2+/− larvae. (H–K) Larvae were treated with vehicle control or 10 μM pyrilamine on day 6. Pyrilamine decreases locomotor activity (H,J) and increases sleep (I,K) for aanat2−/− and aanat2+/− larvae to a similar extent. Bar graphs represent mean ± SEM. **, p<0.01 compared to aanat2−/− (B,C), aanat2−/− DMSO (F,G), or for the indicated comparisons (J,K) by Dunnett’s (B,C,F,G) or Tukey’s test (J,K). Arrows indicate transient artifacts due to pipetting of compounds. See also .