Knowing the life cycles is one of the “basics” that I think should be learnt at a very early stage in beekeeping. Sadly this is often not the case. I have written a suggested learning list where I have suggested that knowing the life cycles should be done by your 4th hive inspection. I really don’t think that is unreasonable as the knowledge is needed in order to manage bees efficiently.
When teaching I like to give the timings from the time the egg is laid, not the time in individual stages. This I think avoids confusion. The timings given in the table below are reasonably accurate, but we are dealing with natural things and they will vary. In recent years I have observed queens in particular can regularly be 3-4 days overdue for emergence. If you remove a queen from a colony there is sometimes still a reasonable amount of worker brood that hasn’t emerged after 23 days.
Queen Worker Drone
Hatches into Larva 3 3 3
Cell Sealed 8/9 9 9/10
Emerges 15/16 21 24
It is my view that beekeeping teachers should teach the life cycles to beginners and why they need to learn them. The most important ones are the dates the cell is sealed for the queen and when she emerges, as this is needed when dealing with swarming and it’s control.