That may very well explain the stumbling bee because they lose muscle function and can no longer fly when temperatures drop down to about 50F.
It is a heartbreaking and frustrating issue with the pesticides being used, killing so many bees and other necessary pollinating insects! I have a half acre pond that is self sufficient as far as taking care of the mosquitoes and their larva with the fish, dragonflies, frogs, lizards, bats, birds and other mosquito eating creatures.
Besides killing the mosquitoes and other pollinators, the pesticides can also destroy the mosquito eaters over time!