In his work "On the Generation of Animals" Aristotle discusses the generation of bees and has no answer to that question. He then says:
"The facts have not yet been sufficiently established. If ever they are, credit must be given to observation rather than to theories, and to theories only insofar as they are confirmed by the observed facts."
quoted from Encyclopaedia Britannica 15th ed. (1994) in Aristotle and Aristotelianism.