Things to do: insect drum

Spring is here.

On a warm night.
... say, 10pm when the world around you is quieter.
Turn off the air-conditioning.
Turn off your TV or any sound or noise making devices.
Turn off the lights in the house.
Close the room door.

Wait 5 minutes... and then turn on the the light in your room only.

And now listen.

You will start hearing lots of insects start to playing the drum against your window glass.

All the light seekers, of different sizes will make different sound for your enjoyment, just because you paused and listen.