Bees have a sense of smell that they use often in their daily activities. Bees actually rely heavily on their senses of smell for protection.
Drone bees that guard the nest must use their sense of smell to sniff out intruders. Each hive has its own particular scent, and any bee without a match to this scent is exiled immediately to prevent intruders from harming the queen. The queen herself produces a pheromone that her workers must be able to smell and identify to recognize her as their queen and impregnate her so that the colony can continue to expand.