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An eclipse gave researchers an inside look at how bees respond to light (smithsonianmag.com)
91 points by shawn 3 days ago | hide | past | web | favorite | 36 comments





I was fortunate enough to be able to see the total solar eclipse in North Georgia. It was kind of freaky when it started to happen. Roosters started calling at the beginning, cicadas stopped, and I heard a very weird humming sound. Once it was dark it seemed like all the insects and animals thought it was night time.

I wonder if nocturnal creatures start coming out like bats.


I saw the most recent eclipse from Western Kentucky. I can't speak about all nocturnal creatures, but I can confirm that bats came out during totality. They also seemed to circle like they didn't have their normal sense of direction at dusk. It was pretty surreal.

> I wonder if nocturnal creatures start coming out like bats

My guess would be no, because nocturnal creatures would be asleep when it happens and so probably not even notice it.


I would have thought that it’s the sun setting which causes them to wake unless they have a perception of time which I don’t think they do.

It might, but I have an anecdote for you.

My pets had an expectation of events to happen at specific times. Dog would sit by the door and 'expect' to see $family_member arrive home from school/work. (noteworthy for those that had regular schedule and always got home about the same time.)

My last cat expected to be fed at the same time every day. For the first couple of years I had my cat, my job & routine were identical every day. Wake at 6am, feed cat, goto work.

On weekends this bothered the cat so he would wake me up at 6:01 so he could get his food. I hated that he would never let me sleep in. Fast-forward a few months to the daylight-savings change; and then at 5:01 he started expecting food. The damn cat had an internal clock that was very accurate.

So I am sure a lot of animals have internal clocks and don't solely rely on "% of sunlight" to determine behaviour.


There is some speculation that dogs use their sense of smell to determine the passage of time. The theory is that when an owner's scent diminishes to a certain point they know that the owner will soon be back. Dogs that normally wait at the door or at a window can be tricked by the reintroduction of the owner's smell and will fail to get ready for the event.

The question is, could an animal do this with no natural light as humans can’t.

What do you mean, humans can't? They can and do.

Not sure where you are located but there was a documentary last night on bbc which demonstrated they can’t. Do you have examples where someone has been able to do this?

A very big part of the sleep-awake cycle is regulated by the circadian rhythm, that is an automatic 24-hour cycle in animals, plants, ... https://en.wikipedia.org/wiki/Circadian_rhythm

It doesn't need light to work. (But light modifies it so after a few days it is synchronized with the local light-darkness cycle.)

So probably all the nocturnal animals that were sleeping in a dark shelter during the day missed the event.


It will probably depend on how noticeable the change is. Sleep/wake cycles are broadly controlled by internal clocks whose timing is synced to day/night cycles via light sensing cells different from those we use to see with.

From personal experience, though, most of us probably know that a bright light in the middle of the night can wake is even if we are nowhere near the point in our circadian cycle where we would be waking up. But a dim light, like a candle, probably won't.

So, I'd expect nocturnal animals in places that are already fairly dark, such as bats that live in caves, to probably sleep right through it, because it will only make a minor change to the light in the cave. Nocturnal animals that live in more exposed places might react, either to the change in light or to the change in temperature.

A bit of Googling indicates this may indeed be the case. Cave bats usually don't react. Forest dwelling bats have been seen to come out.

It would be interesting to do some experiments to see if it is the change in light or the change in temperature that is waking them.


I bet the kids got stung more too. Somewhere between urban legend and scientific fact is honeybees are very good at predicting rain and thunderstorms and will stay in the hive when rain is on the way (and it gets dark in severe storms...). I suppose to the bees, a total eclipse looks like a very intense thunderstorm is about to smash into them, and that makes them hide in the hive. The sting rumor is something to do with bored bees take on guard duty so the law of averages is ten times as many guards means ten times as many stings to innocent beekeepers. In summary most beekeepers know not to work on their hives right before it starts raining and apparently it would be advisable not to work on your hives before a total solar eclipse.

Hives cannot survive long in high humidity, if the interior of a hive gets wet mold will set in rapidly so the bees will work extremely hard to dry the hive out after rain if it gets wet; which probably explains the instinct to hide and stay safe when its about to rain (or, much less often, eclipse)


The article really says bees stop flying any time it is dark, including at night. There's nothing special about their behavior during eclipses here.

Makes you wonder if light pollution is wrecking this process.

There's a lot of orders of magnitude between a light-polluted night and even an overcast day. Your really-quite-good eyes make the difference look much smaller than it really is.

Is it possible that a bee's eyes perform light-level normalization as well?

Low-intensity lights/screens (compared to the sun) wreck havoc on our circadian rhythms, it seems plausible that it disrupts the (not just circadian) rhythms of other organisms as well.


An important question to answer is why this wouldn't be an issue with moonlight.

Sure. Perhaps there's something intrinsically different about moonlight - humans don't have their circadian rhythms disrupted by it, like they do with screens and artificial lights.

Judging from how hard it can be to sleep during a full moon while camping, I'd say the reason humans aren't generally affected by it is because they sleep underneath opaque shelters that block direct light.

This is something I've wondered about. People keep talking about how it's blue light that keeps you awake, but moonlight is pretty bluish. Why would humans have evolved to have that as the don't sleep wavelength?

Moonlight is white, just like how the sun is white. The moon = blue, sun = yellow connotations are mostly cultural.

Just looked it up. Apparently it's due to the Purkinje Effect, i.e. "The tendency for the peak luminance sensitivity of the human eye to shift toward the blue end of the color spectrum at low illumination levels."

I just googled it and apparently moonlight is actually redder (or yellower if you prefer) than sunlight.

Here is a thread with a graph of the spectrum: https://physics.stackexchange.com/questions/244922/why-does-...


You need to be out in open and a very dark place, and with very clear skies, to really notice how bright the moonlight can be - in cities it's just not noticeable. Honestly it never affected my sleep since I was usually dead tired from whole day of hiking and I'm not very sensitive to lights anyways, but I remember on more than one occasion that some people in my group complained not being able to fall asleep or about sleeping bad in semi-transparent tents because of super-bright full Moon.

No, it doesn't make me wonder if anthropic lighting is impacting bee flight. If anything, they can fly later at night.

>If anything, they can fly later at night.

I feel like this is such an American/Capitalist attitude.

It's fine! They'll be more efficient and collect more honey!


Yet another capitalist scheme to make workers work longer hours. I read about it on BuzzFeed.

Top 10 Ways To Maximize Anthophilic Output

I recently walked through a park at night, and noticed that the deer were still up and about. Then I noticed that all along the enclosure there were bright white street lamps. It struck me then, how inconsiderate this was for the deer.

Deer are mostly crepuscular and other than that more active during night time than day time. What you saw likely has little to do with the street lamps.

Sure, but when are they exposed to darkness? When there's a power outage, which hasn't happened within my lifetime.

I'm pretty sure if I had to live with lamps shining on my face all night it would disrupt my circadian rhythm, regardless of when I naturally prefer to sleep.


The point is that deer being active at night isn't an indication of street lamps disrupting their ciradian rhythm. It's possible that those street lamps do affect it, but the behavior you saw isn't evidence of that.

Ok, we've replaced the title with the more compatible-with-that subtitle

The general case they have noticed is nocturnal animals start to become active during an eclipse and animals active during the day time start to shut down like they would during night.

There can be a strong co-relation between sun-light and biological cycles or even metabolism in different living organisms which we may not have discovered. I have noticed that my neighbors dog would go insane during solar eclipse and would start crying as soon as it was over, back in the yard playing. Maybe other living organisms don't understand how eclipse works like humans and they are just scared of unknown.

I witnessed a solar eclipse recently. That night (post eclipse), all the cicada were chirping in perfect unison.



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