After the third or fourth day of emergence, the worker queens mutilate and expel the alien queen from the colony. The current hypothesis for the observed worker bee aggression is thought to be from the wrong blend of queen pheromones released from the alien queen.
On the third or fourth day after the alien queen's arrival, worker bees begin attacking and expelling her from the colony.  The prevailing theory behind this aggressive behavior is that it stems from an incorrect mix of queen pheromones emitted by the alien queen.