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Why flying insects gather at artificial light
- dvh 4y agoPick a random azimuth you want to go. Keep walking while having sun always at the same position and you'll be walking in the straight line. Pick random azimuth you want to go. Keep walking while having street lamp always at the same position and half of you will be spiraling away from the lamp, and the other half will be spiraling towards the lamp forever.
- canadianfella 4y ago[dead]
- MauranKilom 4y agoThis paper specifically provides strong evidence against this explanation: > We also do not observe logarithmic spirals toward the centre of the light source, a key prediction of celestial compass entrapment.
- mkl 4y agoThe key finding of the research in this article is that this is not what is happening. See the "Flight path manipulation via light switching" section and the Discussion section.
- toss1 4y ago>>Pick a random azimuth you want to go. Keep walking while having sun always at the same position and you'll be walking in the straight line. Not quite. That's a good way to get lost in a hurry. Let's pick North as our azimuth, right around sunrise in my location in New England. The sun is rising 77° to the right at 06:00, as I face North and start walking. But the sun moves in the sky, so if I keep the sun 77° to the right of my nose as I walk, by 12:15, the sun is at 167°, and I am now walking due East... I'll be walking in a curve following your guidance here, not a straight line, and the radius will depend on my walking/riding/sailing speed. The same failure occurs for the Moon or any other astronomical object other than the polestar. This is why the invention of portable accurate timepieces was so critical.
- LorenPechtel 4y agoIt works well enough over a reasonably short duration, it doesn't work very well near sunrise/sunset. During the middle part of the day (say 10a-2p) I can be confident that if I'm walking into my shadow that I'm heading approximately north--not perfect but good enough that for gross navigation I'm not going to bother to pull out my phone and look at the map. (I would never be out in the wilderness without *having* map/GPS/satellite texting/headlamp, but that doesn't mean I always *use* them.)
- toss1 4y agoOf course, on a small enough area, short enough time, and rough enough goal, it's fine. The same applies to the earth being round or flat. I don't compensate for the curvature of the earth when figuring out area of bricks for a front walk, or building a shed. So what? With your example, if I'm just trying to walk roughly north in the middle of the day and I know that my destination is just west of mountain slope that I'll see when I get near, then it'll work to just keep our shadows roughly in front of us. But, let's take finding a point on a functionally featureless plain or desert. It's 8 miles away, due North, so a bit over a two hour brisk walk. Local noon (w/DST) is 12:45, so we start at 11:45, and the sun's azimuth is 154°. By the time we get close-ish two hours later (say 7mi at 3.5mph), the sun's azimuth is 207°. So, we started out walking North, but we've been bending to the East, and are now off course by 53° to the East, and our average path is 26° off. After 2 hours at 3.5mph, we should be 1 mile away, due South, and set to arrive in 17 minutes more walking. Instead, we're 3.2 miles away from our objective, and walking 53° in the wrong direction. The zone where this works is really pretty small, and we're probably using landmarks instead. And if you're trying to do this on water without compensating for the earth's rotation, you'll soon be in trouble...
- LorenPechtel 4y agoIt's not nearly that bad. You start heading too far east and bend back. After your two hours you are exactly on the right direction but have gone a bit farther than you needed to and are 26 degrees off course. I've never encountered any large, featureless terrain; rarely am I moving in a direction that's not either with the nature of the terrain or nearly directly across the terrain--it's easier to go a bit farther while minimizing the terrain fighting.
- NoPicklez 4y agoI read this too and they went on to say the following. Other mechanisms might contribute to the arrival of insects at nocturnal light sources over longer ranges. For instance, insects do use celestial compasses for nocturnal navigation, and artificial light sources may interfere with these heading cues. But even at long distances artificial light sources often remain brighter than the night sky and may cause dorsal tilting that would also steer an insect towards a light source. But I thought I interpreted their earlier point that this isn't the reason they're drawn the light. I recently read a book which said that Moths use the moon for the navigation and artificial light throws off that process, becoming entrapped.
- h4ch1 4y agoThis is very interesting and certainly clears up a long held childhood notion that all insects are attracted to the moon (?) makes no sense, but glad to see research on this.
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- sacrosancty 4y ago[dead]
- bee_rider 4y agoIt doesn’t seem that childish. At least for some class of insect — if you are a flying insect that mostly is worried about ground animals trying to kill you, “up” is a pretty good default direction.
- NoPicklez 4y agoI thought this too and recently read a book that said the same thing. But then the paper goes on to say this, which seems to make it still hold true? Other mechanisms might contribute to the arrival of insects at nocturnal light sources over longer ranges. For instance, insects do use celestial compasses for nocturnal navigation, and artificial light sources may interfere with these heading. But even at long distances artificial light sources often remain brighter than the night sky and may cause dorsal tilting that would also steer an insect towards a light source.
- tough 4y agoOk so basically insects are trying to get escape velocity from the light source but their DNA makes them really maintain their back from the light, going in circles for ever
- EamonnMR 4y agoMy quick read of the abstract was something more along the lines of 'insects use the bright sky above and dark ground below to orient themselves, lights create a very different location - dependent up'
- Qem 4y agoWonder if that explains partially the Windshield Phenomenon. Random lamps attacting flying insects kilometers away just to die surely helps decrease their numbers. See https://en.m.wikipedia.org/wiki/Windshield_phenomenon https://en.m.wikipedia.org/wiki/Windshield_phenomenon
- etiam 4y agoI just had a light-bulb moment and came back to say something similar. I'm not sure how well tracked the decline in insect populations is, but I'd imagine light intensity levels during the spaceflight era is pretty much on record. Would be interesting to know to what extent they correlate (and if the answer is "Lots!", I'm inclined to think it is at least not due to insect demise causing rise in artificial lighting).
- MauranKilom 4y agoThe paper in question contradicts your hypothesis. > Only one experiment has tracked moth trajectories to lights over long distances, and found only 2 of 50 individuals released ended their flight at a light source 85m away. This and our results suggest artificial lights may only trap passing insects rather than attract them directly from farther away. (Also: If "death by attraction to artifical light" were a significant factor affecting insect survival, then this evolutionary pressure would certainly cause a rapid change. See https://en.wikipedia.org/wiki/Peppered_moth_evolution https://en.wikipedia.org/wiki/Peppered_moth_evolution.)
- MisterBastahrd 4y agoMe living in the DFW area: This is great! I can open my window at night and feel the cool air blow in and never have to worry about mosquitos. Also me living in the DFW area: I opened my window 5 minutes ago and now I have a hundred crane flies in my office because my light is on. Of course, this is all due to the window not having a screen due to my dog.
- extasia 4y agoWhat's DFW?
- Stratoscope 4y agoDallas and Fort Worth, Texas
- ocay 4y agothx
- deleted 4y ago[deleted]
- SkinTaco 4y agoIt means fort worth, TX. Like how when people say they're from the NYNJ area, it actually means new jersey
- teaearlgraycold 4y agoBrutal
- MisterBastahrd 4y agoBrutally incorrect, perhaps.
- thaumasiotes 4y ago
- zabzonk 4y agoi worked in geneva, switzerland for about 6 months, and in the summer literally every streetlight was surrounded by masses of spider webs - they had worked out that this was where small flying creatures were to be found. strangely, i've never seen this anywhere else, at least not in such profusion.
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- MiguelVieira 4y agoIn Costa Rica I would find toads culstered at the bottom of street lamps, waiting to eat insects that would come crashing down.
- zabzonk 4y agoooh, that sounds nice - i like toads. on my street in london uk i would often find one on the pavement in breeding season, trying to get across the main road on its way to the local big park, which had a pond. i would grab them and carry them across, so they didn't get runover.
- toss1 4y agoHA! Indeed! I have small frogs that climb on the windows in the summer to feast on the bugs attracted to the inside lights. It is wonderous and hilarious to see
- LorenPechtel 4y agoGrowing up I had a cat--she was semi-feral (when we took her in to be spayed the doc found it had already been done, this was before trap-and-release) and had discovered that my father watched TV in the evenings and this made the window good hunting grounds for larger insects. In time I was able to get her trust and turn her into a pet although she was always far more self-reliant than a typical pet. (The idea of going to a human for help didn't seem to be within her thoughts. Empty food dish, she would try to slip into the closet where the bag of food was stored. Trapped in the closet she would simply wait for someone to open it.)
- ChuckMcM 4y agoThat was a great read. I particularly liked that the dorsal orientation was strong enough that a light below the insect would invert it, even if that meant making it crash. I'm going to build an immersible lamp that I can put into a bucket with a layer of oil on the top (viscous fluid) so that the lamp is just below the surface of the oil. Based on the reasoning of this paper, it should result in flying insects inverting and doing a dive into the oil to their demise.
- agentgumshoe 4y agoWhy would you do that?
- ChuckMcM 4y agoTwo reasons, the first being to run an experiment whose result is predicted by the paper, in order to confirm the science in the paper. The second being to mitigate the accumulation of insects around my campsite. While it is true that insect populations world wide have been impacted by the commercial deployment of pesticides by large agricultural operations, it is not true that populations outside that particular affect are negatively affected. Insects, as a fauna, have an extraordinarily effective reproductive cycle relative to the natural hazards they encounter every day. The most recent article about excess honeybee populations was a good example of how honeybees that are outside of the risk zone are not in any danger of becoming extinct but can and do displace important local pollinators. A non-persistent local light trap is the ideal mitigation strategy for insects in a particular regions because it leaves no lasting footprint, doesn't contaminate the food chain, and has zero net impact on the overall population density of the insects.
- jvanderbot 4y agoThe first rule of any bug trap is to put it in your neighbors site. Traps attract more than they kill.
- kingcharles 4y ago
- ubj 4y agoVery cool read. Now when my kids ask me why bugs are attracted to lights, I can tell them the lights act as adversarial misinformation injected into bugs' onboard GNC systems.
- pknerd 4y agoOfftopic: Why both arxiv and biorxiv only provides the PDF version of the text? Why not HTML?
- dilawar 4y agoBiorxiv provides HTML version a few days after PDF ia posted. Rxiv doesnt. AFAIK.
- w-m 4y agoFor arXiv there's https://ar5iv.labs.arxiv.org https://ar5iv.labs.arxiv.org Currently HTML is available for sources up to March 2023, and you need to manually replace the X in the URL with a 5.
- leephillips 4y agoBecause PDF is an excellent, and the universal, format for documents which serves the purposes of science papers quite well, while HTML would be a poor choice for this application.
- tap-snap-or-nap 4y agoWonder how many smaller bugs went extinct because of artificial lights. Humans activity does quite some damage just out of sheer ignorance and neglect. We need exclusive non-human zones on this planet.
- b59831 4y agoAnd where will these zones be? Why do I get the feeling your great idea will be entirely someone else's problem.
- xwdv 4y agoIt’s easy to create such zones. We’ve made such zones before. Simply irradiate a large area of land with nuclear radiation and it will be untouched by humans for hundreds or even thousands of years. I imagine this could be a plot for some eco-terrorism thriller novel.
- worthless-trash 4y agoDoesn't radiating it, end up hurting the creatures that live there ? Essentially mitigating the original reason for doing so ?
- imtringued 4y agoHumans are more dangerous than radiation.
- xwdv 4y agoNot really. They seem fine.
- yencabulator 4y agoChernobyl has lots of wildlife, but the animals aren't healthy. Lack of humans good, radioactivity bad. > Their surveys showed that certain bird species tended to have more genetic mutations, smaller brains and less viable sperm in sites with higher radiation levels. And in 2007, they counted 66 percent fewer birds — and 50 percent fewer bird species — in highly radioactive places compared to background-level sites. > In dozens of studies, the pair also documented that, with higher radiation levels, there were significantly lower numbers of soil invertebrates and a lower abundance of certain insect species and such mammals as hares and foxes. Working with collaborators in Finland, they also documented a range of health effects in bank voles. https://knowablemagazine.org/article/food-environment/2022/scientists-cant-agree-about-chernobyls-impact-wildlife https://knowablemagazine.org/article/food-environment/2022/s...
- KineticLensman 4y agoReminds me of Mitchell and Webb’s moth school lessons: “if the number of lights is two or more, then it’s not the moon, for sure”
- grokgrok 4y agoI chuckled when I read that the authors declared "no competing interests" as if the study could be funded by Big Flashlight.
- notnaut 4y agoSo… Why do bugs bash into lights? Because they think they’re the sky. That seems to be the simplest, most down-to-earth and in-touch with instinct interpretation I can think up for this. The only confusions resting on the word “think.”
- hypertele-Xii 4y agoLots of flying insects fly explicitly to find a mate. My pet theory is that they congregate to lights like a mating beacon, to find each other. After all, fireflies do that bioluminently without assistance. Light carries further than sound, but is expensive to generate.
- tragomaskhalos 4y agointeresting that we are given a glib explanation for this phenomenon at school that doesn't quite make sense, and this finesses it nicely. In similar vein, the simple explanation of why images are inverted in mirrors falls foul of a little probing - e.g why in that case do we not appear upside-down?; there are some good deeper dives into this one on YouTube.
- Doxin 4y agore: mirrors: It's because they don't mirror left-to-right. They mirror front-to-back. Some experimenting with a dry erase marker and a piece of glass will demonstrate this. Write some words on the glass and hold it somewhere in front of the mirror. You'll be able to read the text on the glass and in the mirror simultaneously. The mirror did not flip the text around at all. If instead you write the words on paper it only seems to do this, but notice that between looking at the paper yourself and looking at in the mirror you're doing the flipping of the paper.
- alkonaut 4y agoWhat was the explanation if this wasn't it? The sort of "layman's-explanation" I was given was basically that insects fly in such a way that the light stays fixed in their view - so basically in the same facet(s) of an insect eye during flight, and that this causes them to circle around the lights. This seems to just scientifically confirm the hypothesis we were always told.
- yencabulator 4y agoThe article specifically discredits that earlier notion, and suggests a slightly different one. No: "moon at fixed angle" Yes: "sky is lighter, point topside at illumination to fly level"
- alkonaut 4y agoThat makes sense. But at night that makes it point topside at moon? Which is basically "constantly tilted" of the moon is low? (I read the article, but admittedly quickly, should probably read again)
- atoav 4y agoI once was on am outdoors film set where we used 1.5 kW HMIs from Arri to light a night scene. One of the Arris was a bit beaten up and after a while we saw smoke rise from the lamp. Of course we shut the thing off and went to investigate. Turns out the UV filter of the lamp had a slight gap on one side, a reasonably sized pile of insects had gathered there and started burning in the heat. It must have had something to do with the UV because they were really just gathering in that one spot and all other lamps were more or less insect-free.
- mnemotronic 4y agoSo an ideal bug zapper would have a central light & the zappers coming "out" at 90 degree angle like rocket fins. Guess I should patent this.
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- anonzzzies 4y agoAh yes, another animal we manage to torture. Will we try to fix it now we know? Guess not.
- stinos 4y agoA complete global proper fix probably not, but at least in my area things are now better than a couple of years ago. The main reasons for the changes were mostly economical, but still.. Street lighting is being turned off during the night now, and is being replaced with LEDs with armatures which provide a focused beam. So compared with traditional lighting which was on all night and would illuminate everything within a fairly large radius, and alos upwards, I'd say it's positive overall. Not really related to this particular reasearch, but anecdotally I seemed to be able to confirm https://www.mdpi.com/2075-4450/12/8/734 https://www.mdpi.com/2075-4450/12/8/734 "Artificial Light Lowers Mate Attraction Success in Female Glow-Worms" in that a bigger area of my garden is now less illuminated during the time of the night crucial for glow-worms (because of the focused LED beam), and that area had a higher attraction success; assuming no other factors affect that. But it's really striking how in the well-lit parts females would be sitting on their spot in the grass, day after day, glowing a little bit less everyday towards the end, and then eventually disappear. Likely into death. Which just doesn't seem to happen at all in the darker area.
- bassrattle 4y agoComing home one night, I approached the front door and found hundreds of earthworms crawling up the wall toward the artificial light. Some close to it were sort of tapping on the light. This was before ubiquitous cameras or else I'd have a picture. I haven't found info on this phenomenon anywhere, and this article doesn't offer any explanation of that. I'd like to recreate this, but it might have just been under the most perfect conditions.
- fallingfrog 4y agoObligatory Norm MacDonald moth joke: https://www.youtube.com/watch?v=1-MJy7w69EU https://www.youtube.com/watch?v=1-MJy7w69EU