My pole bean plant and vertical cantaloupe have been starting to look a little yellow and losing leaves on my balcony. While trying to get to the bottom of this, I discovered what appeared to be a small but dense patch of cobweb under a melon leaf. "Spider mites!" I thought. But when I went to wipe the web off, I noticed that there was actually a sizable spider hiding inside! Eep! Weird, I figured it must not be related. Now I have found two other leaves with the same webs and spiders. The first spider was dark, but the two newer ones are pale, almost translucent (babies?). They are way too big to be mites. I'm thinking maybe they are enoplognatha ovata because of the cobwebs and the fact that there is a large bumblebee population visiting these plants for them to hunt. Should I let nature take its course or should I try to eliminate them to protect my pollinators? And is there anything else that the spiders could be that could harm the plants? I still haven't gotten to the bottom of why they are yellowing. I have photos of the leaves, although I can't seem to catch the spiders on film.

Unhappy melon leaf near the base.

The bean leaf problem has spread to a much greater portion of the plants.

Here's what appears to be a dead bumblebee, hinting again that these spiders are after the pollinators even though their webs seem to be on the unhappy leaves.