YHK - yet another hacker news clone

Insects Don't Swarm at LED Lights

73 points speckx 1 hour ago 42 comments

okanat 1 hour ago | parent

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.

Brian_K_White 1 hour ago | parent

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 12 minutes ago | parent

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?

hnlmorg 1 hour ago | parent

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 5 minutes ago | parent

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

quirkot 1 hour ago | parent

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 1 hour ago | parent

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

smallmancontrov 1 hour ago | parent

Nyquist had something to say about that.

quirkot 1 hour ago | parent

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 1 hour ago | parent

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.

nine_k 1 hour ago | parent

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 47 minutes ago | parent

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

inexcf 40 minutes ago | parent

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.

throwaway219450 56 minutes ago | parent

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 29 minutes ago | parent

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

1718627440 11 minutes ago | parent

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).

stevenwoo 36 minutes ago | parent

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.

gopalv 1 hour ago | parent

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

Velocifyer 1 hour ago | parent

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

adolph 1 hour ago | parent

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...

dlcarrier 41 minutes ago | parent

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.

oakwhiz 1 hour ago | parent

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

ChrisMarshallNY 1 hour ago | parent

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

unpleasurable 1 hour ago | parent

Do flames emit UV?

aaomidi 1 hour ago | parent

No but they emit smoke

devindotcom 36 minutes ago | parent

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

officeplant 35 minutes ago | parent

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.

Xcelerate 1 hour ago | parent

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.

Animats 1 hour ago | parent

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 7 minutes ago | parent

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.

theandrewbailey 38 minutes ago | parent

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.

cbg0 31 minutes ago | parent

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

arcfour 30 minutes ago | parent

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

roromainmain 26 minutes ago | parent

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

mcmcmc 15 minutes ago | parent

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

silisili 17 minutes ago | parent

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...

baoooooooooooo 23 minutes ago | parent

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

HelloMcFly 19 minutes ago | parent

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

mahboi 15 minutes ago | parent

The McFlies don't think very much

amelius 7 minutes ago | parent

Are you sure about that?

calt 13 minutes ago | parent

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

mahboi 15 minutes ago | parent

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.