Presumably the queen has evolved to find the DCA's using similar geographic clues to those used by the drones, she just goes further afield. A bit like a single man or woman going to a pub/club/tea dance/rave (delete as appropriate) in the local town as opposed to one more distant. They - males and females, both human and insect - know there will be like-minded individuals gathering in the same place.
The pheromones idea is an interesting one though. This might mean that queens fly upwind to find DCAs. She'd have to work harder to get there but, assuming she used no more than half her strength doing so, would be pretty certain of getting back.
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