Winter cluster with reduced population A tracheal mite infestation shortens the lives of adult bees and affects flight efficiency and perhaps the ability of bees to thermoregulate. As mite populations increase, colony populations dwindle which can ultimately lead to the death of the colony. Many infested colonies die in late winter or early spring when tracheal mite infestation levels are at a maximum and the bee population is primarily composed of older bee. Severely infested colonies can also die during the spring, summer or fall. When a colony is near death, large numbers of bees can be seen crawling out of the hive unable to fly.