Why flying insects gather at artificial light
biorxiv.org
biorxiv.org
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.
> We also do not observe logarithmic spirals toward the centre of the light source, a key prediction of celestial compass entrapment.
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.
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...
Right, you are not ONLY following the sun's direction, you are compensating for it's motion over time, and using the terrain as a guide.
This is exactly my point: we cannot do what GP stated and use only the uncompensated sun's angle as a guide, save for very brief trips. And most of those we're also using landmarks to compensate.
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.
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.
Essentially you are saying that bug zappers actually exasperate the problem they are trying to solve and it would be better to not use one?
I haven't figured out the sweetspot for attractant trap placement yet. It's not inside or attached to your camp or house.
But I know that cold, dry, nonstressed deaths for those that do intrude minimizes the ultimate number that invade via that route. Don't heat them, including by cleaning then up with a standard vacuum.
Interesting facts (according to me): their smell that attracts others is one of those like asparagus, that only some people seem to sense.
But to me smells like burning peanut butter toast crossed with a kaolin/ clay.
Also they hate vibrations/ noise and will aggressively attack and bite in retaliation.
You have a Yoko Ono infestation?
When you kill all those bugs in the first hour of the night, does that leave a noticeable excess-food signal in the region where the dead bugs use to be?
That suggests another interesting test which would be to use a bunch of rope lights to create a complete circle around your site to disrupt all bug flights going in or out of your area. Presumably it could create a higher density at the perimeter of disrupted bugs.
A bug Faraday cage. Neat. Though it could reduce the ambiance of camping by limiting the view of the stars.
If this was your house, maybe, okay. However, when you go camping, you are technically a guest in the bug's house.
But what about kudzo?
> Kudzu, a perennial vine native to Japan and China, was first introduced into the USA in 1876 and was actively promoted by the government as a “wonderplant", It expanded to cover over 1 million ha by 1946 and well over 2 million ha today. When Kudzu invades a forest, it prevents the growth of young hardwoods and kills off other plants. Kudzu causes damage to powerlines, and even overwhelms homes, Kudzu has invaded important protected areas, requiring significant investment of management resources, The management response to date outside the protected areas has been insufficient to deal with this very significant threat.
Sounds like an asshole to me.
Is the OP killing them because s/he has no other alternative to feed himself/herself, or is it because of the annoyance even though s/he is in their habitat?
But defining "the health" of an ecosystem is tricky. An invading invasive species is better adapted after all, and it is part of nature.
We need clearer understanding of what we mean by nature and what we are protecting.
* Are we just trying to hold on to some moment of time in a dynamic ecosystem? Maybe. Protecting the status quo might be practical in terms of human survival, but this doesn't feel like a moral invariant that some people hold it up to be.
* Are we protecting nature in proportion to its ability to feel pain? ... or sentience? ... over what perceptual time frame?
* Practically, so far, when enough people like or find value in certain aspects of nature, we may see some collective action.
As for me, I feel a deep connection with nature, and I recognize this most likely comes from us evolving alongside it. But I recognize my own bias; I care less about mosquitos than birds.
And as to "home territory", mosquitos don't seem to constrain themselves to their homes, whatever that might be. They multiply in little spots of water and go forth seeking blood. To oversimplify, I value human life more than mosquito life. Malaria is a terrible disease. Is this human-centric? Yeah. Do I want humans to continue to grow and destroy nature (whatever that means) as we have done so far? Not really, but I don't know how to practically slow population growth nor development in a way that people will go for. It is a collective will and action problem on a global scale.
Why would you do that ? I understand the science process but if you do this in an hardly reproductible environment (x setup in y location with z group of fauna), how can this confirm anything useful ?
> The second being to mitigate the accumulation of insects around my campsite.
Another reply recommend to use yellow light bulbs, that may also do the trick
Sorry, these light traps you’re using are a natural phenomena the bugs have evolved to be effective against with breeding? Can you elaborate on that line of training?
This has not being happening anymore for a 2 decades...
What about turning lights off around your house a night do they don’t come near you and forget the oil ? You can live in harmony with insects.
I do not hold the same opinion on disease carrying insects. They, regrettably, must be eliminated where people live. It's unclear which insects op is intending to kill. Around here such a campsite trap would net almost exclusively mosquitoes, which count as disease vectors to my eyes.
They will do everything in their power to kill and eat you and give you diseases.
We do need them but harmless? Mother Nature is anything but harmless.
tl;dr: global warming
Even in the late 90's, I must've brought a pregnant tick into the house with me, there were scores of them in my room one summer.
I now live in Anchorage Alaska -- and while there are no deer ticks, ticks that bite dogs have been steadily moving up the coast and are now here.
So I agree about numbers and range extending, but not the timeline you mention. Those suckers were everywhere on the east coast 30 years ago.
- Deer populations are increasing.
- There are no winter killoffs due to warming temperatures.
- Invasive plants like Japanese barberry are becoming extremely common and create microclimates that support mice that ticks live on before attaching to deer.
I believe some tick-borne diseases are becoming more common - I know two people that have had babesiosis, and one person and one dog with anaplasmosis. One of the babesiosis cases was not caught by the hospital in the first go-around and required a blood exchange and almost 2 months in the hospital and rehab.
There is a new invasive insect called the deer ked [0] that crawls like the girl from The Ring and may be a new vector for tick diseases (and they fly!).
Highly recommend checking out the CDC on tick-borne diseases [1], using DEET/permethrin [2] (no permethrin with cats, though), and doing tick checks if you spend time outside.
[0]: https://www.cdc.gov/ticks/tickbornediseases/index.html
Babeosis is stil rare in the northern US.
When you go to a hospital due to a suspected tick bite, keep in mind the standard tick panel does NOT include babeosis screening
You must do a full panel (some 26 tests) in order to detect it. These are often not available in most vet offices.
Babeosis is extremely common in the tropical climate of LATAM. If you take your dog there, and he comes back to the US sick , Consider that your US hospital may be dealing with an exotic disease (unlike LATAM, where this would be a dime a dozen)
I've used those anti-insect yellow lights in all fittings outside my house for years and they dramatically reduce the number and type of all insects, including spiders, hanging about.
On a summer night, you'll see it being full of insects after 1 hour of operation.
We used to have them in a lab I worked in and occasionally a larger insect (e.g. wasp) would get caught between two rows of the grid and you'd hear it spark / them cook...
Is also why I started putting up bird feeders and nesting areas -- they control insects including the mosquitoes, and after seeing just how many were out there...
Bats can contort to fit almost any hole in the house. They are effectively tiny mice.
And just like nice, they make noises with their claws when they get into the walls (they will ryn when not airborne and quite fast too)
And their poop will bring hordes of cockroaches....
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
It seems like the ants stand on the lamps and wait to catch other insects that fly by then strike in unison. It was an incredible strategy.
I once let a small moth-like flying insect live free in my house and later discovered the damned thing had laid eggs in every package of dried plant food in my cupboard, including a few glass jars I thought were airtight, and were crawling with maggots.
As I tossed most of my stored food, I swore to never let another insect in the house again. Praise spiders.
I think the spiders have not so much figured it out as there is a selection bias. Spiders randomly make their nests. The spiders that randomly make a nest near a light source end up with a larger supply of food and grow large. In my current garden, the spiders that end up near a particular fern always grow the largest. My brother used to feed spiders that made their webs in a particular corner of a cabin as a reward for the entertainment they provided when they were building their webs. I have also walked into countless webs from large spiders in the forest over my life.
Everything points to just randomized locations but being near lights generally being good for the lucky spiders that end up there. You will often see spider fights in such locations after a larger moth or other insect breaks the web of one spider and drops it into another spiders web.
You found streetlights in the Peruvian rainforest?
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.
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).
> 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.)
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.
> 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/s...
Counterexample: In permaculture design you intentionally designate part of the site (aka your property) as a wild area called Zone 5.[0]
>Do not touch! Well… kind of. Zone 5 is the “wild child” of all the zones, and one that doesn’t need (and should not have!) any interaction. Do nothing and let nature take its course. Even the smallest permaculture garden should have a zone 5. This zone attracts wildlife, which will encourage diversity and benefit our animals and garden. Zone 5 is a completely wild ecosystem, a great place to observe and learn from nature.
[0] https://www.permaculturenews.org/2017/04/07/five-zones-perma...
Currently HTML is available for sources up to March 2023, and you need to manually replace the X in the URL with a 5.
Guess I should patent this.
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.”
After all, fireflies do that bioluminently without assistance.
Light carries further than sound, but is expensive to generate.
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.
No: "moon at fixed angle"
Yes: "sky is lighter, point topside at illumination to fly level"
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 "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.
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.