BrentD, Your insect observation mirrors my experience in Iowa.

We used to hunt standing corn and often had a difficult time finding downed pheasants hiding in the weeds between cornstocks . Great habitat. Now, we see no weeds in standing corn and almost no pheasants. As for bugs, a longtime farmer told me a few years ago that he had not seen a grasshopper in 4 years. Thank the above situations to Roundup Ready. Great corn, but the habitat and food for birds is poor.

http://www.bakercollectors.com/