What condition is necessary for the successful introduction of a new queen?

For the successful introduction of a new queen, the colony must be in a queenless state, which allows the bees to accept the new queen more readily. When bees recognize that there is no queen, they are more likely to accept a new queen because they are in need of a laying queen to restore their colony's population and hierarchy.

In a queenless colony, the bees are often more receptive to the scents and pheromones emitted by the new queen. This natural instinct drives them to nurture and accept her, thereby ensuring she can take her place as the leader of the hive, lay eggs, and ultimately contribute to the colony's growth and health.

Introducing a queen into a colony that still has an existing queen could lead to aggressive behavior, as the bees may view the new queen as a threat to their established hierarchy. Similarly, other conditions such as a strong population or absence of foragers do not directly relate to the acceptance of a new queen in the same fundamental way as being queenless does.