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Drone and Worker Brood Microclimates Are Regulated Differentially in Honey Bees, Apis mellifera
Background
Honey bee (Apis mellifera) drones and workers show differences in morphology, physiology, and behavior. Because the functions of drones are more related to colony reproduction, and those of workers relate to both survival and reproduction, we hypothesize that the microclimate for worker brood is more precisely regulated than that of drone brood.
Methodology/Principal Findings
We assessed temperature and relative humidity (RH) inside honey bee colonies for both drone and worker brood throughout the three-stage development period, using digital HOBO® Data Loggers. The major findings of this study are that 1) both drone and worker castes show the highest temperature for eggs, followed by larvae and then pupae; 2) temperature in drones are maintained at higher precision (smaller variance) in drone eggs and larvae, but at a lower precision in pupae than the corresponding stages of workers; 3) RH regulation showed higher variance in drone than workers across all brood stages; and 4) RH regulation seems largely due to regulation by workers, as the contribution from empty honey combs are much smaller compared to that from adult workers.
Conclusions/Significance
We conclude that honey bee colonies maintain both temperature and humidity actively; that the microclimate for sealed drone brood is less precisely regulated than worker brood; and that combs with honey contribute very little to the increase of RH in honey bee colonies. These findings increase our understanding of microclimate regulation in honey bees and may have implications for beekeeping practices.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0148740
 

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Interesting study, thanks for posting.

Would you think an open screened bottom board is too much ventilation that adds additional work for the bees to maintain temperature and relative humidity?
 

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JMO, but I've never thought open bottoms were a good idea. Screened bottom boards over a closed sticky board or beetle tray yes but open to the elements no.
 

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The longer I fool with them the less "ventilation" I think they really desire. Thousands of tiny beating wings can move massive quantities of air. Couple this with smaller openings you get better velocity and control of the air flow.

I'm reducing most of my entrances.
 

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Discussion Starter #5
Heat rises - convection! Screened bottom boards are not an issue or hot air balloons would not be open at the bottom. Upper entrances, sticks under the cover, etc. just make the girls work harder. Some commercial beekeepers in the panhandle of Florida think it goes against the nectar to honey process too. The study mentions humidity over capped brood or maybe it was a related study. They all say the same thing.
 

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"...combs with honey contribute very little to the increase of RH in honey bee colonies."

Would this imply that most of the water removal needed to produce ripened honey is performed within individual bees rather than within the open cells of partly-filled honeycombs?
 

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Moisture is definitely a problem in Winter Harley. I was thinking of all the posts with new beekeepers trying to cool the hive the rest of the year. Varroa and small hive beetles are also impacted by temperatures. Varroa grow better in drone cells and note they are neglected in the pupa stage. There is yet to publish research suggesting we need to keep our hives near 96.8 to fight parasites and pathogens. Perhaps it is like the Giant Asian Hornet that dies at 115 degrees when surrounded by honey bees. Warm and fuzzy isn't just for humans!
 

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"...combs with honey contribute very little to the increase of RH in honey bee colonies."

Would this imply that most of the water removal needed to produce ripened honey is performed within individual bees rather than within the open cells of partly-filled honeycombs?
No
 

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"...It takes action (energy) to superconcentrate a solution (sugar syrup). Honey is hygroscopic meaning it absorbs moisture."

That makes sense-- Thanks! This could be a thread by itself ;)
 
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