Answer to Question 1
In a hive, some worker bees serve as guard bees at the hive entrance, regulating all insects that enter the hive. Bees that are not part of the colony are attacked upon attempting to enter. As each worker bee enters the hive, it touches antenna with a guard bee. Bees smell with their antenna and can distinguish between bees that belong to the hive and those that do not. This is accomplished by a pheromone secreted by each bee. A pheromone is a chemical by which organisms communicate.
Answer to Question 2
metamorphosis