"the total mass of local flying insects had fallen by 80 percent in three decades"
Ok, but what if it is now back at the 'norm' and there were just too many insects all those times?
Do we know what the norm is?
I must agree that the quick loss of so many insects does not sound normal. But we also know that insects can swarm very quickly and become a pest in good conditions.
With climate change we have a lot of data from even thousands of years ago, so we have some feeling about the 'norm'.
Does a norm for the total mass of flying insects exist?