Insects don't swarm at LED lights

Posted by speckx 5 hours ago

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Comment by tw04 3 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.

Comment by Izmaki 1 hour 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.

Comment by Freestyler_3 46 minutes ago

Its possible grow lights emit a bit of uv.

Comment by mitkebes 3 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. .

Comment by motionlessveloc 2 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.

Comment by mahboi 4 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.

Comment by sbierwagen 16 minutes 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

Comment by legitronics 3 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.

Comment by hk1337 4 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.

Comment by dylan604 2 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.

Comment by edoceo 1 hour ago

Can we see that? Bet it looks cool.

Comment by dylan604 1 hour 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.

Comment by hinkley 1 hour 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.

Comment by gopalv 5 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

Comment by winrid 3 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

Comment by dlcarrier 4 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.

Comment by raverbashing 3 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

Comment by quickthrowman 2 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...

Comment by Velocifyer 5 hours ago

Don't forget about flicker free dimmable LEDs. I install them in my house.

Comment by adolph 5 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...

Comment by bdamm 4 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.

Comment by throwaway198846 3 hours ago

You assume it is possible to breed out without harming other advantageous behaviors which might not be case.

Comment by piskov 2 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

Comment by dylan604 2 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?

Comment by pasquinelli 2 hours ago

a conclusion can be right even if an argument for it is wrong.

Comment by jmpeax 2 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.

Comment by legitronics 3 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.

Comment by dylan604 2 hours ago

Ever used a blacklight outdoors? They are not bright, but will be covered in bugs.

Comment by Animats 5 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.

Comment by somat 4 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.

Comment by pcdoodle1 2 hours ago

The cozy heat from the IR LED array could be another factor

Comment by okanat 5 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.

Comment by recursive 4 hours ago

Do they cluster around the bulbs? If not, they might not be attracted to the lights.

Comment by Brian_K_White 5 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.

Comment by ninalanyon 4 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?

Comment by aaron695 4 hours ago

[dead]

Comment by hnlmorg 5 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.

Comment by quirkot 5 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

Comment by worldsavior 5 hours ago

There is no such thing as refresh rate for any kind of eye.

Comment by throwaway219450 5 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...

Comment by qqewqe123 4 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

Comment by 1718627440 4 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).

Comment by autoexec 3 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.

Comment by 1718627440 3 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.

Comment by autoexec 2 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...

Comment by stevenwoo 4 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.

Comment by quirkot 5 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

Comment by jschveibinz 5 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.

Comment by nine_k 5 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.

Comment by IanCal 4 hours ago

Are you thinking about saccades? I don’t think I’ve ever seen what you’re talking about with non-flickering sources.

Comment by inexcf 4 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.

Comment by DoctorOetker 1 hour ago

It's called the flicker fusion threshold.

Comment by 5 hours ago

Comment by smallmancontrov 5 hours ago

Nyquist had something to say about that.

Comment by karim79 2 hours ago

I made a huge LED display using lifx tiles (which are no longer sold). 5x5 tiles in a square, so I could hack video rendering and images to the lights. Each tile had 64 LED bulbs which could be independently controlled, both in brightness and colour.

When I did this I was in the countryside and I can state without hesitation that the insects loved it and flocked to it and while I found it cute, it was annoying because they would occasionally get trapped in the small gaps between the tiles and get stuck.

I'm therefore 100% convinced that insects just love fancy lighting setups.

Comment by oakwhiz 5 hours ago

The study didn't cover high pressure sodium bulbs, the previously popular type in street lamps.

Comment by actionfromafar 4 hours ago

The best light.

Comment by nxpnsv 3 hours ago

Wow. I put spotlight on a sheet in the garden to figure out what moths we have. Got nothing, and maybe this is why.

Comment by nemo1618 3 hours ago

The gold standard for mothing is a mercury vapor bulb. They are pricey and power-hungry, but they'll have your sheet covered in bugs in no time!

Comment by vondur 1 hour ago

The outside LED lights on my RV would disagree with this.

Comment by Xcelerate 5 hours ago

I wonder if it’s only the UV that makes a difference. I have some Yuji SunWave bulbs (and the NIR versions). Would be interesting to test those at night against normal LED bulbs and incandescent.

Comment by theandrewbailey 4 hours ago

Maybe this helps answer the question of 'where did the bugs go', because windshields aren't as full of them today compared to 20-30 years ago.

Comment by cbg0 4 hours ago

The answer to that is pesticides. There's still plenty of insects ready to smash into your windshield in many parts of the world.

Comment by silisili 4 hours ago

I wonder what percentage is pesticides vs development? I currently live in an area(US) where a drive to the nearest city of size absolutely coats my car in bugs. US, mostly farmland(soybeans/corn). I wasn't here 30 years ago so can't say there's as many as then, likely not. But if it were only pesticides I'd expect the rural areas to have less bugs than the more developed areas...

Comment by dylan604 2 hours ago

I would lean towards the urbanization of the land as well. I rarely get bugs on my car in the city, but as soon as I head out to the country at night my car is covered. I had to stop at a gas station back in May not for gas but just to squeegee the windscreen so I could see again.

Comment by aeonfox 3 hours ago

As someone who has made many interstate trips through Australia's farmland, I can say that over the decades there's definitely been a drop in windshield splatter. It's unsurprising that pesticide deployed at scale reduces bug populations. Even herbicides which aren't intended as insecticides have limited product advantage to being bug-safe (apart from pollinated crops... and even then). Some aren't even human-safe. An extreme example is paraquat, that while being a herbicide, is irreversibly deadly to humans^ when consumed even in tiny amounts.

^ Obligatory Chubbyemu: https://www.youtube.com/watch?v=0VtUGoGZtI8

Comment by arcfour 4 hours ago

Pesticides weren't in use 20-30 years ago? Wouldn't more dangerous pesticides have been in use then, too, compared to now?

Comment by roromainmain 4 hours ago

They have been used much more massively since the 80s, price decreased significantly.

Comment by mcmcmc 4 hours ago

Yes, and advancements have made them both safer and more effective

Comment by baoooooooooooo 4 hours ago

wow this would be a neat twist if true - we all defaulted to the negative explanation of having killed them all where a much more positive explanation might be that we're no longer luring them to their deaths at the leading edge of automobiles?

I guess it is most likely some combination of the above, but if there's any evidence it would be a neat reframing

Comment by faidit 2 hours ago

Colorado: "Insect biomass declined by ∼47% and abundance declined by ∼61.5% over the last 35 years." https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2...

Germany: "More than 75 percent decline over 27 years in total flying insect biomass in protected areas" https://journals.plos.org/plosone/article?id=10.1371/journal...

Puerto Rico: "dry weight biomass of arthropods captured in sweep samples had declined 4 to 8 times, and 30 to 60 times in sticky traps." https://www.pnas.org/doi/10.1073/pnas.1722477115

Comment by HelloMcFly 4 hours ago

The mass insect-death on windshield issue was as much a daytime issue and nighttime one.

Comment by amelius 4 hours ago

Are you sure about that?

Comment by Angostura 3 hours ago

Yes. The daytime crop was always greater than at night

Comment by mahboi 4 hours ago

The McFlies don't think very much

Comment by dylan604 2 hours ago

I think they just all collectively got tired of hearing my dad's punny about "it doesn't have the guts to do that again" any time a bug squashed on the windscreen.

Comment by calt 4 hours ago

My hypothesis is better wind tunnel testing for modern cars so that the bugs go over instead of splatting.

Comment by dylan604 2 hours ago

I'd go with fewer people having experience driving not in a city, at least in this forum making the claims as GP

Comment by shmerl 1 hour ago

Why can't LED lights have the same warm yellow tone? These pure white street lights are much worse than than the old style warm ones.

Comment by ChrisMarshallNY 5 hours ago

I have noticed that. We have LED porch lights, and never see the usual moths and whatnot.

Comment by speransky 1 hour ago

In coastal Florida we require to use turtle-safe light fixtures, mine are 585nm and they didn't attract insects too except potato bugs

Comment by 3 hours ago

Comment by HeyLaughingBoy 3 hours ago

Um, no. I live on a farm and often have to do chores in the dark with an LED headlight. Sometimes I have to turn it off because I'm dive bombed by so many insects.

Comment by skeezyboi 3 hours ago

because they dont emit UV.... a lot of waffle to tell me that

Comment by unpleasurable 5 hours ago

Do flames emit UV?

Comment by officeplant 4 hours ago

Yes, but how much UV depends on what's burnin / how hot its burning. Otherwise they mostly put out IR.

We use UV/IR combo Flame detectors at work for this purpose.

Comment by bell-cot 3 hours ago

IIR, hydrogen flames can emit enough of their energy in the UV for that to be a serious issue - both direct human exposure, and degradation of exposed surfaces and equipment.

Comment by devindotcom 4 hours ago

a little but not much, from my quick look online.

Comment by metalman 3 hours ago

lived with candles and kerocene lanterns, etc for years and the odd bug will go nuts and spiral in, but not very many but all in all, there are way less bugs everywhere now

Comment by aaomidi 5 hours ago

No but they emit smoke

Comment by lakeviewterrace 3 hours ago

What lies.

I bought LED "bug lights" — those yellow bulbs that are supposed to be invisible to bugs.

Every bulb in the pack electrically failed within 10 minutes.

I gave up and went back to an incandescent. Still works perfectly.

So sick of the zero-quality LED bulbs that have entirely flooded the market. Of course they had their hand forced by government mandates, people needed mass quantities of cheap bulbs that could match a 75¢ incandescent. They didn't have this problem when LED bulbs were $20 each (and weighed about as much, due to the heat sink).

Comment by AmazingEveryDay 2 hours ago

It was always a scam because LED bulbs need power supply and that creates heat, switching hundreds of volts ac to low volt dc. They don't last any longer than incandescent in fact they have much shorter lifetimes.

Comment by mikestew 1 hour ago

They don't last any longer than incandescent in fact they have much shorter lifetimes.

Tell that to my 10 year old Philipps Hue lights. I wonder if there is some other quality at work that would explain the difference...

Comment by lakeviewterrace 1 hour ago

Average lifetime of my Philips bulbs is ~ 8 months before they develop the 'flicker of death'... at roughly $7/bulb I might as well go back to black market incandescents.

Comment by dylan604 2 hours ago

A cheaply made bulb doesn't really support your theory though. Before LEDs, the anti-bug yellow incandescent bulb was available. It puts of a horrendous light and most people didn't like them. It's in the top 3 of lights that I do not like: 1) anything CFL, 2) any cool white (>3600K) light at night, 3) ugly yellow anti-bug light, 4) whatever the ugly greenish light 7-11 uses at some gas stations, 5) 4300K fluoro tubes.

Comment by lakeviewterrace 2 hours ago

It's in a garden shed, so...

Comment by 2 hours ago