Brood volume
What is the approximate brood volume as a function of the queen’s egg-laying capacity? How many brood frames does the queen need in order to lay eggs without space limitation?
We recall that, in theory, a Dadant brood frame contains, on its two sides, 8'692 cells of 5 mm width. In practice, since frames are not entirely and perfectly built, one can assume about 7'000 cells per Dadant brood frame on its two sides.
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We know that the development of a fertilised egg (worker) comprises three stages: for 3 days, the egg is positioned at the bottom of the cell. On the 3rd day a larva hatches; it will be fed for 6 days, first with royal jelly and then with honey and pollen, before capping, which lasts 10 days for the pupal stage. Finally, the imago emerges on the 21st day. We recall that the queen’s egg-laying varies depending on multiple factors: season, nectar/pollen flows, temperature/weather, swarming, etc. Assuming that the queen lays the same number of fertilised eggs (workers) each day and that the brood is free of disease or parasitosis, how many frames are required for her to complete her 21-day laying cycle without being limited by available space, i.e. without a laying blockage? If the queen lays 1'500 eggs per day regularly, she needs 4 frames to complete a full 21-day cycle (1'500 eggs x 21 days : 7'000 cells = 4 ½ Dadant brood frames). Likewise, if the queen lays 2'000 eggs per day, she will need 6 brood frames. Finally, if a particularly fertile queen lays 3'000 eggs per day, the brood will cover 9 brood frames. Conversely, if during inspection one observes 3 brood frames completely covered with brood of all stages, one can infer that the queen lays about 1'000 eggs per day: (3 frames x 7'000 cells : 21 days = 1’000 eggs per day). In practice, egg-laying is centred in the middle of the frame, often leaving more or less wide crescents of pollen/honey around the periphery. The brood area is very rarely perfectly homogeneous and the queen lays irregularly. Estimating the queen’s egg-laying therefore requires a bit of approximation. With experience, a good glance brings you close to the truth … |
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