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.
谢谢申明博光临指教！知了在很热的晚上也是会叫的，很不好意思，俺小时候很淘，经常和男孩子们晚上去沾知了，不叫的话，俺们怎么能发现涅，俺们又没有红外眼镜，哈哈，所以啊 申明博主，A little knowledge is a dangerous thing！哈哈，至于荷发吗，赠魅衫吗，您不能意会，那是您自己的事，和咱无关哈。请您下次见到俺的园子绕着走哈，第一咱是自乐加上和朋友一起乐，不欢迎不速之客，第二，老让您在俺的园子里闹笑话，俺于心不忍呀！哈哈哈！
