Do Bees Sleep?
Updated: 12th February 2021
Do bees sleep, do they sleep at night, and if so, where and how do we know they are sleeping?
As one of the most studied creatures on the planet, it’s no surprise that scientists have asked many questions, including “do bees sleep?”
Please note, that all of the research contained in this article relates to honey bees. I make some remarks about bumble bees later.
Do bees sleep?
The short answer to the first question is: according to scientists, YES, bees do sleep!
How do we know bees sleep and how do they sleep?
To answer this question, scientists say that it all depends on how we define ‘sleep’, and it seems that the state we refer to as ‘sleep’ in humans and mammals is also witnessed in bees!
Put another way: physical states observed in humans and mammals as they sleep, are also seen in honey bees. We can therefore surmise that bees do indeed sleep!
Sleep in honey bees is similar to mammals in the following ways, including:
1. Relaxed body posture, and not moving (immobile)
When a bee is in deep sleep, they have a distinct sleeping posture. Their antennae droop downwards,
the upper body (thorax) drops as does the tip of the abdomen (or tail), and the wings rest on the body.
Look closely, and you can see this in the images below1. In the first image (A), the bee is alert: it has its wings up and extended, the whole body is off the ‘floor’, and antennae are facing forward. As the bee falls into a deep sleep in picture D, the antennae are drooping and the body and wings are relaxed.
This image is from the scientific paper; ref: Eban-Rothschild, A. D. and Bloch, G. (2008). Differences in the sleep architecture of forager and young honeybees (Apis mellifera). J. Exp. Biol. 211,2408 -2416
2. Drop in body temperature
Scientist also found that the body temperature of bees drops
when they sleep, which is also the case with humans.
3. The deeper the sleep, the harder it is to wake the sleeper!
It is even the case that the deeper a bee is sleeping,
the brighter the light needed to wake the bee1, which again, tends to be the same with humans.
4. Brain patterns
Finally, certain distinct patterns happen in
the bee brain when bees are sleeping.
When do bees sleep? Do bees sleep at night, or do they sleep during the day? At what time do bees sleep?
In honey bees, there is some variance depending on the role within a
colony.
Foragers
Forager bees (the older worker bees
within the colony), are active during the day, but sleep at night back in the
nest or bee hive. Foragers go through different sleep stages of light sleep and deeper sleep, and when awake they may be immobile for a while (not moving) or may groom.
Young workers
Very young worker bees (whose duties include cleaning the cells), also sleep in the hive or nest, but they have no fixed
pattern of sleep as the foragers do. Instead, they may be active during day or night, with periods of sleep (or naps) in between, spread out over a 24 hour period.
Scientists say they found no consistent differences in the amount of time that foragers
and young workers spent sleeping.
However, scientists suggest that young bees may be in need of regular naps because their ongoing interaction with other bees tires them out.
Where do bees sleep?
Honey bee workers typically progress through a set of tasks, beginning adulthood as cell cleaners, later tending brood and the queen as nurse bees, then receiving and storing nectar as food storers, and ultimately serving as the colony's foragers, thus foragers being the older worker bees in the colony.
Scientists investigated whether the role of the honey bee worker within the colony influenced where the bee sleeps5. Older worker bees generally slept outside cells, closer to the edge of the nest, in cooler areas, and away from uncapped brood.
Younger worker bees generally slept inside cells and closer to the center of the nest, and spent more time asleep than awake when surrounded by uncapped brood.
Why do bees need sleep?
It seems bees need their sleep, because otherwise (just like humans), their performance is hampered.
Scientists found that bees deprived of sleep:
- were not able to waggle dance properly2, and
- have difficulty learning a new route home3,
- may also show signs of sleepiness during the day, for example by moving their antennae less4.
What do bees do when they wake up?
As stated, researchers found that the first thing older foraging honey bees do, is groom when they wake or they may remain motionless for a while. They may then either go back to sleep, or get on with their usual roles within the colony.
A video of bees sleeping?
Here's a short video. Look at the posture of the two resting bees at the front bottom left of the the screen!
Where do bees sleep in winter?
Please see my page ‘Where do bees go in winter?’ for more information.
What about bumble bees?
I have not found a specific piece of research investigating this, but I certainly
believe bumble bees sleep, and in particular, I have observed bumble bee males in the
morning, apparently sleeping on flowers, such as cosmos, lamb’s ear, buddleia and lavender among others.
When asleep, they are immobile, with drooped antennae, and it may take a little while for them to wake up!
References
1. Rothschild, A. D. and Bloch, G. (2008). Differences in the sleep architecture of forager and young honeybees (Apis mellifera). J. Exp. Biol. 211,2408 -2416
2. Barrett A. Klein et al. (2010). Sleep deprivation impairs precision of waggle dance signalling in honey bees. PNAS – Proceedings of the National Academy of Sciences of the Unites States of America. vol. 107 no. 52 22705–22709, doi: 10.1073/pnas.1009439108.
3. Beyaert, L., Greggers, U. and Menzel, R. (2012). Honeybees consolidate navigation memory during sleep. J. Exp. Biol. 215, 3981-3988)
4. S Sauer, E Herrmann, W Kaiser, Sleep deprivation in honey bees. J Sleep Res 13, 145–152 (2004).
5. Klein BA, Stiegler M, Klein A, Tautz J (2014) Mapping Sleeping Bees within Their Nest: Spatial and Temporal Analysis of Worker Honey Bee Sleep. PLoS ONE 9(7): e102316. https://doi.org/10.1371/journal.pone.0102316
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