radx said:

The data of the study came out of Germany, where the effects of a change in temperature are much more moderate than in many other areas. Basically, this decline is attributed mostly due to farming, the saturation of everything with pesticides, and, generally speaking, the destruction of the ecosphere. Even worse, this is in a country with comparably extensive regulation on all these matters, unlike, say, India.

As you say, this really is no bueno.

Driving past fields of rapeseed in the late '90s meant a windshield full of bugs. We used to head into the fields wearing yellow shirts just to see who can get the densest armor of bugs. Now, I can walk past the very same fields outside the town I grew up in with less than 5 bugs on a yellow shirt.

Or how about another anecdote: when I grew up, barbecue in my (grand-)parents yard meant paying attention to all the wasps, so that you don't swallow one by accident. I haven't seen a single one over several barbecues this year. Bees and bumblebees are still around, though less plentiful, but wasps are a complete no-show. Haven't seen a hornet in two years.