Fireflies "holding up their lanterns" are actually "strutting their stuff" to members of the opposite sex. Because daylight greatly interferes with the light fireflies produce, they are nocturnal animals like owls and bats, active at night and resting during the day.
至於它們「退在晦而能明」的賢臣美德，是由於白天日光對螢光干擾太大，因此它們和蝙蝠、貓頭鷹一樣，屬於「夜行性動物」，在黑夜活動，白天停棲在樹上。