Does the Busy Nurse Bee Ever Sleep?
She doesn't sleep much, seems to be the answer based on new research by a Hebrew University team of researchers.
Honeybees are as willing as humans to forego sleep to take care of their newborns.
When a worker bee emerges from metamorphosis as a young bee, she cleans up the honeycomb cell she was born in and becomes a nurse bee for her first 3 weeks of life. Her duty is to care for newborns and for the Queen Bee. Before becoming a forager that brings pollen and nectar to the hive, she spends her time caring for the other young ones coming up behind her.
While all eggs in the colony are laid only by the Queen, who lays up to 1500 eggs per day, the many nurse bees carry the eggs to solitary cells in the honeycomb where it takes 3-4 days for them to gestate before hatching.
This brilliant 3:22 minute long video by National Geographic gives a great snapshot of the life cycle of a worker bee:
As the eggs hatch, the nurse bees care for the larvae by feeding them ‘bee bread’ which is a combination of pollen, honey and royal jelly, a secretion from the nurse bee’s salivary glands. After feeding the larvae for 3-4 days with this blend, the devoted nurse bee seals the cells with beeswax. Ten days later, adult bees emerge from these cells.
The ratio of bee types in the apis mellifera beehive is very disproportionate. There is only one Queen Bee, perhaps 200-300 drones whose sole job is to mate with queens from other hives, and as many as 80,000 sterile female worker bees.
So, the life of the worker bee begins as a nurse bee for her first week in the new world after emergence, where she cares for the queen bee, feeds the larvae, and makes honey. Her short career as a nurse bee ends after one week, when she joins the maintenance crew for 1-2 weeks, making beeswax, ventilating the hive, building and repairing honeycomb. Her next graduation will be to the role of forager. This final job of gathering pollen and nectar for her colony takes her outside her home into an unknown world of danger. It lasts from about 3 weeks old to 6 weeks old, when she dies.
According to previous research, a worker bee can adjust her sleep patterns depending on her role in the hive. When she forages, her waking and sleeping cycles are strong, but while she is a nurse bee, she works around the clock caring for the brood and seems to do just fine on less sleep.
Researchers were surprised to find that it was neither the pupae nor any pheromone-like chemicals produced by the pupae that caused sleep deprivation in the nurse bees. When the pupae, which do not need to be fed, and their chemicals were removed, the nurse bees did not enjoy better sleep patterns. They seem to be hardwired to sleep less during the nurse bee cycle, perhaps because they are young and energetic. They can sacrifice sleep without it affecting their performance.
The study was published in the journal Current Biology last week. One of the Hebrew University team’s findings was that sleep is more fluid and less rigid than it was previously thought to be. More research may follow to better understand if the nurse bee has a mechanism that allows her to reduce her sleep needs without paying a price, as in brain function. This would raise the question about what sort of mechanism it might be, and what the basic function of sleep is.
If you stop and dwell upon the inherent intelligence in the structure of a honeybee colony, a sense of awe is inevitable.
The entire life of the worker bee is a life of service. To queen and colony, to her sisters and even to the drones who do nothing to help her. This blog post is in honor of the tireless and busy worker bee.
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