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Posted by speckx 17 hours ago

Insects don't swarm at LED lights(www.birdsoutsidemywindow.org)
281 points | 136 comments
tw04 14 hours ago|
I have LED headlights and an LED light bar on my tractor and I can say with 100% confidence that bugs swarm both. To the point I have to wear glasses to keep them out of my eyes if I’m on it for more than about 30 seconds at night.

I’m guessing he’s confusing the dramatic drop in insect life overall with a change in behavior due to different lights.

Izmaki 12 hours ago||
I second this. When my home was infested by flies (I stopped counting at ~1000 over a 3 week period) they would always swarm and hang out by my grow lights (full spectrum LEDs) in my kitchen window. It was a great place for fly traps on the flip side.

It is quite possible that flies prefer one part of the light spectrum more than another part, but to say in the title that they don’t swarm at LEDs is misleading at best.

InsidiousWombat 2 hours ago|||
Might be something to do with PWM.

Also the light bulbs have excellent performance at "catching" bugs because they land on hot stuff and die. I had some GU-12 ceiling halogen lights in my previous apartment and the rims were always covered by bugs that decided to land there and as they were hot from halogens, boom, bug destruction machine

Freestyler_3 12 hours ago|||
Its possible grow lights emit a bit of uv.
_heimdall 3 minutes ago|||
Aren't full spectrum grow lights intended to emit UV?
joshspankit 9 hours ago||||
I would even say it’s very likely. Most Blue LEDs emit UV, and a lot of other-coloured LEDs are blue with a phosphor coating
NamlchakKhandro 10 hours ago|||
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mitkebes 14 hours ago|||
Insects are attracted to low wavelength light, which includes both UV and blue light. Cool color LEDs are usually blue LEDs, and are often used for headlights/etc because they get higher lumen ratings for the power used. Headlights/lightbars are also really bright compared to porch lights.

If you compare an incandescent soft white porch light to a similar brightness soft white led light, you will probably see dramatically more insects at the incandescent bulb. .

motionlessveloc 14 hours ago|||
From TFA:

> We found that LEDs attracted significantly fewer insects than other light sources, but found no significant difference in attraction between the “cool” and “warm white” LEDs.

mrheosuper 8 hours ago|||
All white led is Blue/UV led.
nomel 7 hours ago||
This is actually many many millionth's of some fraction of a percent false! ;)

https://news.ycombinator.com/item?id=50327058

wopwops 10 hours ago||
Yep, my Fenix headlamp and flashlights attract flying insects like crazy.
eth0up 6 minutes ago||
My nichia based Acebeam, Fenix and Zebra as well. Florida is a good place to test this.
mahboi 15 hours ago||
Welp, they do for mine. I've had to stop turning on outdoor LEDs because angry bees kept showing up, and there'd be 3-10 dead ones on my doorstep every morning. These are white bulbs. Might be "zombees."

Also, not sure about white bulbs, but those color-configurable spotlights definitely emit UV at least when set to anything near blue/purple. They cause certain things to glow. Probably white is doing it too but it's harder to see.

legitronics 14 hours ago||
The color configurable bulbs or the high CRI bulbs typically use a 400nm led source and some do use a 380nm but those are much rarer and expensive. Also almost any amount of plastic or glass will significantly absorb that wavelength of UV.

I have a 405nm laser pointer and it makes certain things (any% titanium dioxide) absurdly bright from fluorescence. So you probably aren’t getting UV from those bulbs, but certainly some IR.

sbierwagen 11 hours ago|||
You don't need UV to stimulate florescence. 395nm blue light will cause yellow highlighters to light up quite brightly: https://par.nsf.gov/servlets/purl/10326338
mrheosuper 5 hours ago||
UV-A starts from 400nm, so there is no "395nm blue light"
Dylan16807 1 hour ago||
400nm by virtue of aggressive rounding. 395nm is well inside the visible range.
hk1337 15 hours ago||
Yeah, we have solar powered LED lights in the walking path where I live and the lights are covered with them. They look nasty.
gopalv 16 hours ago||
My pet theory is that the dimmable LEDs repel insects (when used as a grow light).

The thing that insects can see and we don't is the rapid flashing of a PWM power controller.

I wonder if these streetlights have power saving fade-ins as the nightfall approaches instead of clicking on at sunset.

Like - https://doi.org/10.1109/CSNT51715.2021.9509652

winrid 14 hours ago||
This. It likely depends on the driving technology. Some repell me too :P

Note you can make LEDs dim without PWM via constant current drivers, just less efficient as the duty cycle is 100%, they look much nicer though

nik282000 10 hours ago|||
PWM drivers should be banned, the quality of lighting is horrendous and it murders LEDs. You have an rms currernt that is in spec but the peak is way too high.

anecdote: I work in a factory, we have thousands of light fixtures. The older constant current LED fixtures have lasted a decade, the new PWM driven lights have had a ~1% failure rate.

skew-aberration 9 hours ago||
How do you know the difference? Constant current is almost certainly a PWM controlled buck/boost regulator. The flicker is attenuated by inductance, more or less depending on the design.
dchristian 6 hours ago|||
Use a fidget spinner to see the difference. Spin up a 3 lobe fidget spinner and catch the reflection of the LED on it's surface. As the speed changes, a flickering LED will freeze the motion of the spinner. Even more fun with spinners :-).

Yes, adding an inductor will fix the problem, but that costs money. Not enough customers are complaining about the light flicker to justify the higher price.

nik282000 7 hours ago|||
I guess the distinction is 'filtered' vs 'unfiltered' then. If you look at the lights that fail early using a high framerate camera (1k fps) they flicker between full brightness and fully off. The lights that last longer have some ripple but its 5-10% brightness.
excannuk 10 hours ago|||
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andai 8 hours ago|||
One of my favorite things I read growing up was a passage about what it's like to be a fly watching TV.

In those days TV's were big CRT boxes, illuminated by the electron beam which would race across the screen row by row.

A housefly's "refresh rate" on its eyeballs is much higher than that of a human, so the fly wouldn't see an image as we do, but would presumably find it quite relaxing watching the dot of light slowly move across the screen.

temp123477 5 hours ago||
In those days. Oh no! I'm old.
Velocifyer 16 hours ago|||
Don't forget about flicker free dimmable LEDs. I install them in my house.
mdasen 7 hours ago||
Yeah, while a lot of LED bulbs are bad, some LED bulbs have ever so slightly less flicker than incandescent bulbs.
dlcarrier 16 hours ago|||
The streetlights in my neighborhood still have the round photo sensors on top, that have something like a watt of standby current for the sensor itself. I don't think they're trying hard to save powwer.
raverbashing 15 hours ago|||
The ones that have a watt of standby are the really old models (probably not sold for the last 30yrs) where you'd have an LDR controlled relay with no electronics

Anything more modern than that, even if it has a similar case, will use less power

quickthrowman 13 hours ago|||
A low-voltage photocell uses like 5mA @ 24VAC these days, it’s nowhere near a watt. You can buy a wireless battery powered photocell or occupancy sensor that will last a decade.

This Acuity occ sensor/photocell combo draws 4mA @ 24VDC: https://pdmassets.azureedge.net/library/SS/documents/specshe...

adolph 16 hours ago||
The article bluntly states: "Moonlight contains ultraviolet (UV) and infrared wavelengths because it is merely reflected sunlight. Insects cue on UV, believing it to be the moon. . . . Incandescent lights transmit UV but LEDs do not. Insects are far less attracted to LED."

However, my mind developed a similar conjecture to your's: what if the common frequencies of PWM occur within a kinetic visual blindspot of insect vision, like human saccades [0] in the novel Blindsight [1], so that insects are not aware of the LED at all?

0. https://www.ncbi.nlm.nih.gov/books/NBK10991/

1. https://www.rifters.com/real/Blindsight.htm#:~:text=%22There...

bdamm 15 hours ago||
Are we giving too little credit to the insects?

They've had many generations to evolve alongside all human false light sources. Insect generations are usually pretty short. Perhaps they just find it evolutionary useful to cluster around human sources of light. Presence of human food, liklihood of bumping into other insects of the same species, warmth, etc.

If human sources of light were interfering somehow, they've had hundreds or thousands of generations to breed out that proclivity.

throwaway198846 14 hours ago||
You assume it is possible to breed out without harming other advantageous behaviors which might not be case.
dylan604 13 hours ago||
I love to shoot long exposure timelapse of the night sky. I set up a couple of LEDs dimmed as low as possible to light a bit of the foreground (over the course of the long exposure the low light adds up so it looks normal for those not familiar). Out of sheer laziness, I just placed them on either side of my tripod. The next day after processing the shot, it was pretty much ruined because of all of the bugs showing up as tracers in each frame.

So, no, not my experience at all.

hinkley 13 hours ago||
Bugs don’t just materialize out of the ether to swarm lights. Not to feed swallows. They are there and you will encounter them if the density is much more than zero.

There are bugs. You photographed bugs. Maybe more than you would have without lights at all, maybe about the same.

Also better lights don’t necessarily mean perfect lights. We do lots of things to reduce harm. Unfortunately sometimes we do them too much and conserve a significant fraction of the original harm by increasing demand.

andai 8 hours ago||
>Not to feed swallows.

I often visit a place full of swallows and mosquitoes. The swallows eat mosquitoes, and the mosquitoes eat me. So when I get bit, I joke I'm feeding the birds.

d3Xt3r 1 hour ago|||
Is that African or European swallows?
hinkley 6 hours ago|||
The circle of life!
edoceo 13 hours ago||
Can we see that? Bet it looks cool.
dylan604 13 hours ago||
I was afraid I'd get a "pics or didn't happen" request! Even though that's not that's why you're asking. I don't know that I have the footage any more. I wasn't happy with it, and that was many many moons ago. It's not something I would have spent a lot of effort making copies of.
Joel_Mckay 8 hours ago||
Could have keyed your external camera flash to a relay driver for the lights. Blinking them on for 1 second every 5 minutes shouldn't get gross moth dust on everything.

Also different insects are blind to various areas of the spectrum LED lights cover. So you just get different creatures showing up.

An incandescent filament bulb will probably give you warmer color in the deeper reds. Too high of a color temperature at night makes things look odd, and you may not immediately notice the HDR capture is skewed.

https://www.amazon.com/dp/B000I17G4O

The neutral "Bright White" Philips A19 Ultra Definition Frosted Dimmable LED Bulbs are about as good as you can get with cheap retail consumer E26 bulbs. Still, the weaker reds may to be an issue depending on what you are capturing, and one may have to drop to a lower color-temperature indoor version like "Soft White". =3

dylan604 6 hours ago||
I've experimented with this, but for single images exposing a person at shutter open, and then letting the person leave frame while continuing to expose the sky.

Having a strobe every exposure during a timelapse is annoying though. You'd get run out on a rail at a star party with nonsense like that. Sometimes, it really helps to think about others when doing your own thing and not being an asshat just because you want to do something

Joel_Mckay 5 hours ago||
Could also try filtered low-pressure sodium lamps, as notch filtering out the light pollution is pretty trivial.

Maybe converting the yellow area of the image into grey scale would give you the highlights, and the color loss could look intentional in moonlight.

There are plenty of intervalometer options around, and even a few Arduino projects for the creative.

Best of luck, =3

piskov 14 hours ago||
The entire premise (moon uv, ir etc) is wrong so the conclusion is wrong.

Sky is always brighter than the land, moon is not required.

Lamp movement is the confusion of where is “up”

https://www.nature.com/articles/s41467-024-44785-3

dylan604 13 hours ago||
> Sky is always brighter than the land, moon is not required.

Speaking of things being wrong...how can you come to this conclusion? There are many beaches where turtle hatchlings get confused by all of the lights on land where they crawl away from the ocean instead of towards it. Land is so bright, that the vast majority of humans can no longer see the night sky. So again I ask, how do you come to the conclusion that land is darker than the sky?

lmz 9 hours ago||
I think the missing part is "in the absence of artificial light".
dylan604 6 hours ago||
In "the absence of artificial light", please explain how land will be brighter than the sky
Scarblac 5 hours ago||
It wouldn't, that's his point.
pasquinelli 14 hours ago||
a conclusion can be right even if an argument for it is wrong.
jmpeax 13 hours ago||
If P then Q, P therefore Q. Q is not the conclusion, it's just the consequent. If P is false, then Q could be true, but claiming Q is true because P is true when P is actually false is a wrong conclusion.
pasquinelli 8 hours ago||
i don't see what point your making.

take something you know to be true. now come up with a stupid, falacious argument for it. now you can see that seeing an argument is bad doesn't mean the conclusion is wrong.

jkahrs595 43 minutes ago||
I’m not even going to open this because the title is so wrong.
legitronics 14 hours ago||
I really don’t think UV is playing much of a role here. You could also sort their chart by power usage, or IR produced. The paper conclusion paragraph even states UV and IR as candidates but the article just says UV.
dylan604 13 hours ago|
Ever used a blacklight outdoors? They are not bright, but will be covered in bugs.
nkrisc 10 hours ago||
Don’t those bug collectors (the big white sheets) biologists set up at night usually use UV lights?
Spare_account 1 hour ago||
And the insect killers in kitchens
quirkot 16 hours ago||
I wonder how much of it is also the LED flicker. If I was a small bug and moving quickly with a high visual refresh rate, I would probably hate the experience of the LED flicker
worldsavior 16 hours ago|
There is no such thing as refresh rate for any kind of eye.
throwaway219450 16 hours ago|||
There are odd visual illusions though, like humans perceive the Wagon-Wheel Effect even though there's no obvious reason it should happen. This is the effect where the speed of a rotating object varies depending on its sync with a discrete exposure period.

https://en.wikipedia.org/wiki/Wagon-wheel_effect

https://research.tue.nl/en/publications/subjective-strobosco...

qqewqe123 15 hours ago||
You mention it yourself, these illusions only occur with "discrete exposure periods". This is moreso related to video recordings and less about how the eye sees actual physical objects. Such illusions do NOT occur with natural light.

Edit; to be clear there is a version of the wagon wheel effect under natural light, I'm just saying that the main one with discrete exposure periods does not occur irl

throwaway219450 5 hours ago|||
> You mention it yourself, these illusions only occur with "discrete exposure periods".

Have a look at https://www.pnas.org/doi/epdf/10.1073/pnas.93.8.3693; my point was that there is documented research that says even with continuous illumination and an (apparently) continuous camera (the brain), this happens:

> The illusion of wheels or other radial patterns rotating back- ward in continuous light, together with the perception of supernumerary spokes, suggests that the human visual system processes sequential episodes of information rather than a continuous temporal flow. In addition to accounting for this remarkable illusion, a strategy of vision that parses the world in this way can explain why movies are so realistic (simply because that is the way we normally see things) and how we detect motion (by comparing the position of the same objects in sequential episodes).

1718627440 15 hours ago|||
What? Have you never looked at another car's wheel on the highway? Or is that something that only occurs to some people (doubt it).
autoexec 15 hours ago||
Eye vibrations can cause the effect to be visible to the naked eye. If even humming can do it, the road vibrations might too.
1718627440 15 hours ago||
I'm confused. I thought seeing/measuring lower frequencies due to a low sampling frequency, where the lower perceived frequency is basically the modulus of the real frequency and the sampling rate, is a well-known phenomenon independent of the actual sensor implementation.
autoexec 14 hours ago||
I guess it is, but it's unclear why it happens outside of recordings. https://www.livescience.com/32406-what-makes-wheels-appear-t...
stevenwoo 16 hours ago||||
I highly recommend the pop science book An Immense World by Ed Yong to disabuse you of this notion. There is a sort of refresh rate (not exactly the same but good metaphor) for everything at every level of living being we study. It gives enough information for you to read the actual studied should you have more questions after reading it.
nine_k 16 hours ago||||
There is for the visual cortex though.

Try walking outside in a clear night. Look up, notice some stars, or aircraft lights. Now rotate in place, and see how low your vision's FPS is in the dark: the rotation will be visibility jumpy.

An insect, with its much simpler visual processing, and facing a bright light, will likely achieve a much higher FPS, sufficient for the sub-kilohertz flicker to be very visible.

IanCal 16 hours ago|||
Are you thinking about saccades? I don’t think I’ve ever seen what you’re talking about with non-flickering sources.
inexcf 16 hours ago|||
For a game i tried to model the behavior of our eyes in the dark and read up on a lot of that stuff. Not once was there a suggestion of jumpy vision. And that is also not my experience. In low light things begin to smudge, lots of ghosting the further in the periphery of your view they move in.
quirkot 16 hours ago||||
Yeah, i know that's how the physics works, but effectively my computer monitor doesn't flicker for me but a strobe light does. Whatever the proper term for that is what I'm talking aobut
jschveibinz 16 hours ago||||
But there is a neurological component in "optical processing" that can be modeled as a discrete rate of update although the underlying physiology is still being investigated.
andai 8 hours ago||||
I can often see the refresh rate of lamps, especially out the corner of my eye.

I'm told insects are more sensitive in that regard, due to having brains with fewer layers.

smallmancontrov 16 hours ago||||
Nyquist had something to say about that.
DoctorOetker 13 hours ago|||
It's called the flicker fusion threshold.
okanat 16 hours ago||
Weird. My home has only LED bulbs. There are still moths and bees who get attracted to the light when I leave the window open.
hnlmorg 16 hours ago||
I think it’s to do with the LED flicker. You can sometimes see it in your peripheral vision (ie your light/dark receptors) but your RGB cones aren’t as good at spotting it.

Insects eyes are biologically very different.

With LED lighting, if you have lots of spot lights in the ceiling and and open door, you’ll likely find that the light leaving the house is a bath of reflection from different sources inside the house and that likely cancels out the worst of the flicker.

recursive 15 hours ago|||
Do they cluster around the bulbs? If not, they might not be attracted to the lights.
Brian_K_White 16 hours ago|||
Install a single incandescent somewhere and be less mystified by the claim.

They didn't say no bug ever goes to any led light.

ninalanyon 15 hours ago||
But it is what the title on HN says. Is it too much to expect something like "Insects swarm less at LED lights" if that is more truthful?
prmoustache 6 hours ago|||
Probably but is it too much to expect something like reading the article before commenting? We all know that many articles/blog posts titles on the internet are clickbait.
Brian_K_White 5 hours ago||||
It is not what the title says, either literally, explicitly, or by implication. The title is already exactly fine.

Is it too much to expect super smarty hn developer types to know how to read? Yeah looks like.

aaron695 16 hours ago||
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Animats 16 hours ago|
Yes, you need some ultraviolet to attract insects. That's why bug-zappers have near UV lamps. They're usually compact fluorescent bulbs. Some ads say 365nm is the right color.
somat 15 hours ago|
I get quite a few insects that fly around a camera, and that is near-ir. So many that a spider finds it worth it's while to build a web in front.
pcdoodle1 14 hours ago||
The cozy heat from the IR LED array could be another factor
andai 8 hours ago||
Can confirm my spiders like cozy heat. I often get them chilling directly above my computer station, legs spread out like a pancake. Presumably there's a warm air current hitting the ceiling. It might also be the light though.
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