Turns out large microphones are more sensitive, in general. Like here, they use a 1" microphone, I believe, to record a snail munching lettuce and a caterpillar tap dancing: https://www.youtube.com/watch?v=zJH5n_HdNkA
Remardkable. So it's a very sensitive condenser mic, and a very low noise preamp. I wonder if this would be enough for the spiderweb. Glass and lettuce are a lot louder, I think. And you'd probably want it physically coupled to the web.
