The melatonin concentration from cohort worker bees showed a daily rhythm: the melatonin level in day time was higher than that in night, and the highest melatonin level is 285.32 pg/bee at 5: 20.

• 同龄工蜂在同一天中的褪黑素具有日节律变化，基本是白天低夜间高，最高值出现在清晨5：20(285.；32pg/蜂)。