I have a colony of orb weavers on my balcony.
Watching spider hunting activity has been so fascinating!
Spiders don't have ears but they 'hear' through the many different length hairs on their body especially their feet. Once they've built a web they cut the web around a signal line so it's only attached to the center of the web and then hide with a foot on the signal line.
If something impacts the web the movement on the center can be felt and the spider rushes to the center placing its legs on the radials to detect where in the web. It then plucks the radials it thinks might have something on them. The vibration change caused by weight allows them to feel where the item is or to make it wiggle more. They then attach a line to the center and run down to the spot, if it's nothing they want, they just let go and zip back up to the center to listen to the strings again. Eventually going up the signal line to hide again.
TLDR: Spiders hunt using the music of their web.
