I live in the Midwest and the first time I noticed the lack of mosquitos was in 2017. I still don't see any to speak of. Not that I "miss" them, but it was a "blip" that I noticed back then. In the years after 2017, each year you noticed less bees, then less butterflies, wasps, etc. In the last year, I have noticed more sweat bees, a very few more honey bees, more wasps, and just this summer... , a butterfly here and there. I still don't see mosquitos here. The weeds are crazy this year, with all the humidity and rain. We cut hay yesterday, and the weeds are are like cutting pencils. The quality of the hay will be poor. The cows and horses will not be impressed this year. We will have to supplement their feed more heavily going forward.