Bumble bee queens hibernate. According to the Miriam-Webster site, hibernate means “to pass the winter in a torpid or resting state; especially : to pass the winter in a torpid condition in which the body temperature drops to a little above freezing and metabolic activity is reduced nearly to zero.”
Estivate, on the other hand, means “to pass the summer in a state of torpor.”
If you’ve ever watched a bumble bee, it is extremely active in summer and excess heat doesn’t seem to be an issue. In fact, most bees live in hotter and drier climates. Once a nest with workers is established, the bumble bee queen stays in the nest while the workers go out foraging. But the queen is not in a state of torpor, she is actively laying eggs and raising brood.
However, only bumble bee queens hibernate over winter, each one living separately in a small hole in the ground. The rest of the bees from her colony, the female workers and the males, die with the advent of freezing weather.
If you can’t tell a bumble bee from a honey bee, here is some help.