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Why flying insects gather at artificial light

nature.com

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Re: Why flying insects gather at artificial light

#41

Post by joemi »

stinos wrote: post #30
bee_rider wrote: post #28

Earlier quoted context omitted.

I’m not sure if there’s interesting optimization to do. Simply: bugs are attracted to light, light=more bugs, no light=fewer bugs. Motion detectors, for example, can make it so that the light is only temporary and you don’t get those moth parties.

bugs are attracted to light Isn't the takeaway from this study that they aren't really, but rather that once they happen to come close to it they cannot get away from it anymore?

The effect is the same (for the purposes of an outdoor dining area), and I believe that's what they were referring to. Perhaps a better way to word it would be: bugs will go towards a local light.

Re: Why flying insects gather at artificial light

#43

Post by blauditore »

The paper tries to make it sound like it solved a long-standing mystery, while it basically just confirms the most obvious explanation: Insects use artificial (close) light sources like a natural (distant) light source for navigation, which makes them eventually spiral towards the light most of the time.

The methodology and resulting graphics are interesting, but the underlying geometry of the effect is not really new or surprising.

Re: Why flying insects gather at artificial light

#44

Post by moffkalast »

SamBam wrote: post #31
mapreduce wrote: post #29

Earlier quoted context omitted.

I don't think it confirms that. It seems to be one of the popular theories they investigated. Later they say - "In both field and lab conditions, insects rarely head directly towards, but consistently fly orthogonal to the light source. This refutes the fundamental premise of an escape response." "An insect should keep a light source at a fixed visual location for maintaining its heading. Switching light position (Su…

I think you're misunderstanding GP. This definitely refutes the theory that insects are trying to escape towards the light, because, as the article shows, insects don't head directly for the light, but instead move orthogonal to it. But this doesn't mean they can't use moonlight to help with flying. The theory, as I understand it, is that they use a distant light source -- e.g. the daytime sky -- to maintain altitude…

Wait, so it could be a parallax thing?

The moon is in practical terms infinitely far away, and no matter how far the insect flies it won't budge and stay as a stationary feature to localize by.

But do the same with a lamp that's only 3 m away, and keeping it in the same spot can only mean flying around it in circles, towards, or away from it, otherwise it'll move around a lot relative to the insect observer.

Re: Why flying insects gather at artificial light

#45

Post by martopix »

blauditore wrote: post #43

The paper tries to make it sound like it solved a long-standing mystery, while it basically just confirms the most obvious explanation: Insects use artificial (close) light sources like a natural (distant) light source for navigation, which makes them eventually spiral towards the light most of the time. The methodology and resulting graphics are interesting, but the underlying geometry of the effect is not really ne…

Yeah, I feel this was taught to me in primary school or something.

Re: Why flying insects gather at artificial light

#46

Post by patall »

teeray wrote: post #38

It’s always amusing in the garden center at Home Depot looking at the enormous spider webs (and the fat spiders) around their sodium vapor lamps. It must be that the number of calories required to produce bioluminescence to create this effect must be greater than the calories that could be derived from hunting that way. But if someone else provided that free energy for hunting…

Or you are observing evolution in action. A bioluminescent spider would likely be an easy target for birds or bats. One by the lamp is not because hunters have simply not adapted yet. Or maybe, spider webs used to be enormous and profitable everywhere, only that insects dying globally makes them profitable now only in those light spots.

Re: Why flying insects gather at artificial light

#47

Post by pavedwalden »

jgilias wrote: post #37
codetrotter wrote: post #27

So am I understanding correctly that this confirms the common perception they cited: > Insects use the moon as a celestial compass cue to navigate, and mistakenly use artificial light sources instead

That’s my understanding too. The way I thought about this before was that normally an insect would ‘keep the moon’ on one side to navigate straight, but artificial light messes that up and they end up spiraling around those light sources. Which seems exactly the behavior that they have demonstrated in the research.

I think the moon theory was almost right, but I didn't see any reference to insects keeping the light source to one side or the other. The researchers seem to think that insects orient as if the brightest thing they see is "up".

Re: Why flying insects gather at artificial light

#48

Post by mapreduce »

jgilias wrote: post #37
codetrotter wrote: post #27

So am I understanding correctly that this confirms the common perception they cited: > Insects use the moon as a celestial compass cue to navigate, and mistakenly use artificial light sources instead

That’s my understanding too. The way I thought about this before was that normally an insect would ‘keep the moon’ on one side to navigate straight, but artificial light messes that up and they end up spiraling around those light sources. Which seems exactly the behavior that they have demonstrated in the research.

> they end up spiraling around those light sources

What I'm struggling to understand is how the insects then reach so close to the artificial light. Why don't they spiral the artificial light from a great distance like 1 metre or 2 metres away? I see the insects hovering like millimetres or centimetres away from artificial light.

Re: Why flying insects gather at artificial light

#49

Post by tzs »

nashashmi wrote: post #21

I have a feeling the stars are used by insects to navigate in pitch dark environments. And the lack of stars may be causing a large decline in insect population. Making a road trip in the light polluted northeast america, I was looking for stars in the darkest of forested of environments, and I could not find any stars anywhere. I am not sure if the clouds were there. But I realize I have not seen stars in a long tim…

It depends on what you count as using stars. Insects don’t have good enough eyes to see individual stars, but dung beetles can see the Milky Way and use it for navigation.

Re: Why flying insects gather at artificial light

#50

Post by darkwater »

scotty79 wrote: post #9

I had a really weird observation. Do you know how in the summer flies tend to enter rooms and circle the middle of it (where usually the turned off light fixture is)? And they seemingly can't or don't want to find open window to leave the room? At one point for unrelated reasons I replaced light fixture in my room with more than 200W worth of strongest E27 Philips LED lightbulbs I could find (20*1521lumen). Few flies…

This actually squares with the study, no? I mean, when they are inside - and it's my experience as well - they might take the window as the main source of light and think that's the sky, so they start to fly in circles.
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