During a lunch break at work I was taking a walk along a huge water cooling unit when I have seen a beetle caught in a spider web. Since I of course did not have my camera on me, I have done my best with my phone.
At first I thought the spider is nowhere near, but it only took a while to crawl out of its hiding under one of the metal covers. The spider did not approach the beetle at first, and when it did it only felt it with its front legs and then backed off because the beetle was thrashing around and it was about as big as the spider itself.
Then a few moments later the spider has tried to drag the beetle upward, but it did not work. The beetle was evidently too big and too strong for that and it fought back valiantly.
After that the spider crawled away from the beetle and I thought it gave up. After all the beetle was tearing the net apart. But then the spider has surprised me. It has merely changed its tactic. It crawled along the edge of the web and coordinated its collapse so as the beetle was tearing the silk threads, instead of freeing itself it got more and more constrained in movement. I did not know that spiders can do that.
When the beetle was constrained enough – destroying about 50% of the web in the process – the spider approached it again and has done its spin wrap of the prey into a cocoon.
All that was left after that was the final blow – the spider has sunk its chelicerae into the side of the beetle, presumably between the plates of its chitinous armour. That took a few minutes and the poor beetle was still trying to move.
I checked up on the place before I went home. At first I did see neither the spider nor the beetle. I found the spider hidden under the metal cover again, with only its front legs protruding outward, holding the packed beetle and waiting for the digestive juices do their thing.
I have observed spiders hunt before, but the tactic of collapsing the web around bigger prey was new for me.