The amount of insects present those days is really decreasing by a lot, and this is definitely a huge problem for the future. It is clear that agriculture will be strongly affected, but in fact the problem is much larger. I remember a time, back in the days, where driving 1000 km yielded a windshield completely covered with dead insects. Today, the windshield ends mostly clean for a similar trip. This is in my opinion the most shocking proof of something being wrong, and this proof can be felt by anyone who is old enough.
I do not know whether this is to you that I wrote the above statement recently, in another blog. If this is the case, I apologies for having written it again.
RE: Functional biodiversity: Bumblebee and its presence in agro-ecosystems