Answer： Cicadas may sing at night. The truth is, in most cases they do not. However, there are a few cases when cicadas will sing at night:
(1) In the presence of artificial light sources, like streetlights & flood lights, or a full moon. I turned on a flood light tonight to test this and it worked: a cicada started to sing. (2) When it’s extraordinarily hot. (3) If the cicada is disturbed or attacked. (4) If they’re overcrowded.
謝謝申明博光臨指教！知了在很熱的晚上也是會叫的，很不好意思，俺小時候很淘，經常和男孩子們晚上去沾知了，不叫的話，俺們怎麼能發現涅，俺們又沒有紅外眼鏡，哈哈，所以啊 申明博主，A little knowledge is a dangerous thing！哈哈，至於荷發嗎，贈魅衫嗎，您不能意會，那是您自己的事，和咱無關哈。請您下次見到俺的園子繞着走哈，第一咱是自樂加上和朋友一起樂，不歡迎不速之客，第二，老讓您在俺的園子裡鬧笑話，俺於心不忍呀！哈哈哈！
