system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: While I was on the observation deck (103 stories/1300 feet up) of the Willis (sears) tower, I noticed there were a lot of spiders on the outside of the windows. How do the spiders get up there and what do they eat to survive?
gpt
Spiders will kite, using their silk as balloons, to float in the air and get to other places.  This is how spiders can invade islands that are in the middle of the ocean.  There are also insects that will kite like a spider, caterpillars and mites, and those are probably in the spiders' diet.  Gnats are also something they like.

I think this problem is especially pronounced in Chicago.  It's apparently the Orb Weaver spider, and they are all over the place on Chicago high-rises.  The spiders ride the lake winds up and up and up.