What advantage would the inside spiders have? Surely they wouldn't catch any bugs?
Or are they building a structure that's attractive for bugs to enter? What's the strategy for this web?
midges can fly, so presumably they would hit the web at random points. as to why flying would be useful for the midges, if they consume biofilms on the surfaces, that's less clear. perhaps over time the midges will evolve away from flying and the spiders will have to adjust their strategy.
They may have more chances to change their skin unnoticed in the silent place.
The article mentions that the caves are filled with millions of midges providing plenty of food.