Deep Dive
新加坡的知了：一首热带的交响乐，也是一场听觉盛宴（或灾难）
新加坡的正午，阳光炙烤着大地。空气中弥漫着热浪，而另一种声音则更加醒目：知了的鸣叫。这并非普通的虫鸣，而是充满节奏感的乐章，一首热带的交响乐。
这种独特的节奏，起初稳定而规律，随后逐渐加快，最终汇集成一种持续不断的单音，仿佛一首被无限拉长的音符。 然而，这种“乐章”的音量惊人，大量的知了同时鸣叫，足以造成永久性听力损伤。这可不是闹着玩的。
与美国东部地区周期性出现的十七年蝉不同，新加坡的知了活跃于一年四季。十七年蝉每隔17年才集体出现一次，数量之多，令人叹为观止；而新加坡的知了，则日复一日地演奏着它们的“交响曲”。
雄性知了是这支“乐队”的演奏者。它们的鸣叫声，包含着一个完整的循环：从稳定的节奏，到逐渐加速，再到持续的单音，最后归于沉寂。仔细聆听，你会发现这其中蕴含着奇妙的规律。
有趣的是，如果你在阳光灿烂的日子里站在树下，感觉像是下起了“雨”，那很可能不是真的雨，而是知了在“方便”你。
这段音频录制于新加坡实里索炮台 (邮编 099981)。 这片土地上，知了的鸣叫声，构成了新加坡独特的声音景观的一部分，既是自然之声的魅力展现，也提醒着我们，即使是再动听的乐章，音量过大也可能带来伤害。 这热带的交响乐，需要我们以恰当的方式去欣赏。
Shownotes Transcript
If you time the chirping of crickets, there's a simple formula you can use to figure out the ambient temperature. But in Singapore, at midday, with cloudless blue skies, you already know it's hot. Which is just as well, because those are cicadas. Cicadas.
In eastern USA, 2021 is when brood exocardas emerged from underground for the first time in 17 years. Yeah, 17 years. These are periodic exocardas, and when they come out, they come out by the trillions. They mate, the female lays eggs in tree branches, those hatch and fall back to the soil. The young nymphs then burrow down, and they disappear for 17 years.
It's the weirdest life cycle of any creature on earth. Cicadas in Singapore, on the other hand, are active all year round and the noise of cicadas can be heard all day long. When you get a bunch of them together, the sound can be ridiculously loud, to the point of causing permanent hearing loss.
It's the males that sing, and the cycle consists of an initially constant rhythm, which speeds up and eventually becomes a continuous note, before falling silent. Listen carefully. Here's one full cycle. Oh, by the way, if you're standing under a tree on a sunny day and feel raindrops, it's likely to be cicadas peeing on you.
You've been hearing cicadas. Here is Fort Siloso, postal code 099981. Check out this episode's show notes for more information or visit our website, hearhere.show.