While there isn't an insect officially designated as "the king," the bee is often referred to as the king of the insects.
It's important to note that in many social insect species, like bees, wasps, ants, and termites, there are queens, whose primary role is reproduction (laying eggs). These queens are essential for the continuation of the colony. So, while "king" is sometimes used informally for the bee, it's not a scientific designation, and the concept of royalty in insect societies is actually more often associated with queens.