there were about ten percent double > queens, but I saw no link to aggressive behaviour. Hi Tim, Ron Brown used to lecture on his 2 queen system. Copies of his pamphlet are still available although he doesn't lecture much nowadays as he is 95 now. One of the benefits he cites for the 2 queen system is improved temperament, which he puts down to the extra queen pheromone in the hive. Chris -- Visit www.honeybeeworld.com/bee-l for rules, FAQ and other info ---