Edit: interestingly, I see a lot of honeybees and some wasps foraging, both on the leaves and flowers of the tilia, but it’s only the bumblebees that lie dead on the ground.
Every summer, there are dozens of bumblebees either dead or dying beneath tilia trees (linden/lime/basswood).
Why?
My father once told me (some 20 years ago?) that they die from “overeating”. With all due respect to his linden tea (thanks dad🩷🩵🤍), this sounds like folklore…
If starvation due to the nectar is the cause, then my next question would be, what is the major pollinator for the trees? Or is what they get from everything good enough that evolution doesn’t kick in to make this a dead end feature for the tree. Maybe their blooming cycle is different than others, so they tend to dominate at that time and get enough activity even with the deaths?