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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 mistake

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

mapreduce 3y ago
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 (Supplementary Fig. 5) shows that insects readily hold the light source on either side of the body." It makes sense to me. Imagine you were an insect and you would use the moon for navigation. Would you really be flying directly towards moon? No, right? Then how could someone think that insects flying directly towards artificial light source is the basis for the theory that insects use moon as navigational aid?
- SamBam 3y ago
  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. There's no reason they couldn't use the moon to do this too. Again, they would not be flying towards the moon, they'd be keeping the brightest light to their dorsal side. Since the moon is distant, unlike a lamp, this would result in steady flight. I'm not sure that it confirms whether they use the moon or not, but it seems like a possibility.
  - moffkalast 3y ago
    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.
    - jameshart 3y ago
      The spiraling in might also be a kind of vertigo response as well. Normally the moon only goes up or down in your field of vision if you’re adjusting your angle - pitching or rolling. But an artificial light source moves up or downwards if you’re changing altitude but maintaining attitude. That would make flying up past the light ‘feel like’ pitching away from it, which might cause autonomic steering responses, similar to inner ear/visual conflicts causing humans to stagger and fall over.
  - CobrastanJorji 3y ago
    Okay, something I'm confused about. "Dorsal side" means, as far as I can tell, your back. So if a fly is keeping its dorsal side facing the moon, that means its back is pointing at the moon. When the moon's directly overhead, this makes lots of sense. Fly goes around wherever. But if the moon's low on the eastern horizon, would we expect flies to mostly be facing upwards, and mostly flying west?
    - dclowd9901 3y ago
      Doesn’t it just make more sense that they orient their movement in relation to the moon? Doesn’t matter what the specific orientation is — if the moon is 3 inches across and sitting in a room, it’s gonna fuck with the insect’s navigation.
- Retr0id 3y ago
  If your logic is "keep the brightest light source on your left", then for a light source that's nearby (as opposed to "infinitely" far away, like the moon) you'll end up orbiting it. Depending on your precise navigation logic, you'll either end up with an increasing or decreasing orbit radius. If it decreases, you'll eventually crash into the light source.
- rdtsc 3y ago
  > Imagine you were an insect and you would use the moon for navigation. Would you really be flying directly towards moon? No, right? Then how could someone think that insects flying directly towards artificial light source is the basis for the theory that insects use moon as navigational aid? If you're flying parallel to the ground (horizontally), you'd want the moon to be where your back is and you'd have a good change of flying straight. It's like when the kids say that the moon seems to "follow" them. "Dorsal" means where the top part is, the insect's back, as it were.
  - jameshart 3y ago
    What’s so special about keeping it ‘where your back is’? The moon is rarely located directly overhead. Wherever it is, keeping it in a fixed relative position will get you going in a straight line. The article talks about the ‘dorsal flight response’ being more about the overall alignment to the sky hemisphere, not the moon specifically. “the brightest part of the visual field has been the sky, and thus it is a robust indicator of which way is up. This is true even at night, especially at short wavelengths (<450 nm)”
    - rdtsc 3y ago
      > What’s so special about keeping it ‘where your back is’? Since we're to imagine the grandparent flying around like an insect. I imagined them as person flying but with insect wings. Since we're mammals with eyes pointing straight ahead, as opposed with them being on the side of our heads, we'd need some light sensor on our back to ensure we're flying straight at night and keeping the moon above, as opposed to having to look behind every so often to ensure the moon is still there :-)
jgilias 3y ago
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.
- pavedwalden 3y ago
  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".
- mapreduce 3y ago
  > 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.
  - codetrotter 3y ago
    See this comment by another user ITT: > 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. https://news.ycombinator.com/item?id=39195508 https://news.ycombinator.com/item?id=39195508 Seems a reasonable explanation to me :)
  - aeternum 3y ago
    The larger the distance, the more it actually works as a navigational source so you won't see those insects since they are navigating just fine. The insects you see are the ones that happen to get too close and thus their nav gets 'jammed'. It's similar to planes navigating by compass. Works great, until you go up to the arctic circle, then you better have another nav source or you too will be flying in circles.
Berniek 3y ago
>Insects use the moon as a celestial compass cue to navigate, and mistakenly use artificial light sources instead I think that was one of the theories being investigated by this research. The paper demonstrates that it is the actual light (of the moon or stars or sun or artificial source) they use to orientate themselves in the horizontal plain BUT that is not navigation. With a "tilt" in their orientation they will fly in circles around the light but this tilt also causes inefficiencies in their actual flight mechanism so will cause erratic directional stability as their flight path rapidly changes their spacial relationship to the light source. Whatever their navigation imperative (heat, cold pheromones,smell, sight, sound) will be affected by this spacial relationship instability.
_xerces_ 3y ago
I think a lot of the comments are also missing the fact that the moon is an unreliable means of navigation due it not always being present the whole night (or at all), changes brightness, moves around the sky and can be covered by cloud. It is unlikely then that insects would specifically evolve to use it as a means of navigation. The paper states that it is the general brightness of the sky, even at night, compared to the ground that is the point of reference. So insect point top side at diffuse bright area and bottom side will be parallel to ground.
- conductr 3y ago
  It seems to me they are using it, but as you mentioned navigation may not be the purpose. There may be none. It may just be that insects that do this congregate and reproduce thus it’s just a mate finding thing that’s evolved. Since insects often have short lives, I’d guess it also explains why they’re always doing it (they need to mate asap). Might also explain why they don’t go directly to the light but eventually end up there circling it erratically, increased odds of bumping into a mate.
  - consp 3y ago
    The paper mentions that the insects enter stall conditions, maybe due to the banked orientations, sometimes and then recover. This would explain erratic behaviour without any mate present.
mihaaly 3y ago
More like using the sun/sky to adjust their attitude of flying. Everyday, not only when moon is visible.

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

mapreduce 3y ago

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 (Supplementary Fig. 5) shows that insects readily hold the light source on either side of the body." It makes sense to me. Imagine you were an insect and you would use the moon for navigation. Would you really be flying directly towards moon? No, right? Then how could someone think that insects flying directly towards artificial light source is the basis for the theory that insects use moon as navigational aid?

SamBam 3y ago
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. There's no reason they couldn't use the moon to do this too. Again, they would not be flying towards the moon, they'd be keeping the brightest light to their dorsal side. Since the moon is distant, unlike a lamp, this would result in steady flight. I'm not sure that it confirms whether they use the moon or not, but it seems like a possibility.
- moffkalast 3y ago
  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.
  - jameshart 3y ago
    The spiraling in might also be a kind of vertigo response as well. Normally the moon only goes up or down in your field of vision if you’re adjusting your angle - pitching or rolling. But an artificial light source moves up or downwards if you’re changing altitude but maintaining attitude. That would make flying up past the light ‘feel like’ pitching away from it, which might cause autonomic steering responses, similar to inner ear/visual conflicts causing humans to stagger and fall over.
- CobrastanJorji 3y ago
  Okay, something I'm confused about. "Dorsal side" means, as far as I can tell, your back. So if a fly is keeping its dorsal side facing the moon, that means its back is pointing at the moon. When the moon's directly overhead, this makes lots of sense. Fly goes around wherever. But if the moon's low on the eastern horizon, would we expect flies to mostly be facing upwards, and mostly flying west?
  - dclowd9901 3y ago
    Doesn’t it just make more sense that they orient their movement in relation to the moon? Doesn’t matter what the specific orientation is — if the moon is 3 inches across and sitting in a room, it’s gonna fuck with the insect’s navigation.
Retr0id 3y ago
If your logic is "keep the brightest light source on your left", then for a light source that's nearby (as opposed to "infinitely" far away, like the moon) you'll end up orbiting it. Depending on your precise navigation logic, you'll either end up with an increasing or decreasing orbit radius. If it decreases, you'll eventually crash into the light source.
rdtsc 3y ago
> Imagine you were an insect and you would use the moon for navigation. Would you really be flying directly towards moon? No, right? Then how could someone think that insects flying directly towards artificial light source is the basis for the theory that insects use moon as navigational aid? If you're flying parallel to the ground (horizontally), you'd want the moon to be where your back is and you'd have a good change of flying straight. It's like when the kids say that the moon seems to "follow" them. "Dorsal" means where the top part is, the insect's back, as it were.
- jameshart 3y ago
  What’s so special about keeping it ‘where your back is’? The moon is rarely located directly overhead. Wherever it is, keeping it in a fixed relative position will get you going in a straight line. The article talks about the ‘dorsal flight response’ being more about the overall alignment to the sky hemisphere, not the moon specifically. “the brightest part of the visual field has been the sky, and thus it is a robust indicator of which way is up. This is true even at night, especially at short wavelengths (<450 nm)”
  - rdtsc 3y ago
    > What’s so special about keeping it ‘where your back is’? Since we're to imagine the grandparent flying around like an insect. I imagined them as person flying but with insect wings. Since we're mammals with eyes pointing straight ahead, as opposed with them being on the side of our heads, we'd need some light sensor on our back to ensure we're flying straight at night and keeping the moon above, as opposed to having to look behind every so often to ensure the moon is still there :-)

jgilias 3y ago

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.

pavedwalden 3y ago
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".
mapreduce 3y ago
> 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.
- codetrotter 3y ago
  See this comment by another user ITT: > 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. https://news.ycombinator.com/item?id=39195508 https://news.ycombinator.com/item?id=39195508 Seems a reasonable explanation to me :)
- aeternum 3y ago
  The larger the distance, the more it actually works as a navigational source so you won't see those insects since they are navigating just fine. The insects you see are the ones that happen to get too close and thus their nav gets 'jammed'. It's similar to planes navigating by compass. Works great, until you go up to the arctic circle, then you better have another nav source or you too will be flying in circles.

Berniek 3y ago

>Insects use the moon as a celestial compass cue to navigate, and mistakenly use artificial light sources instead I think that was one of the theories being investigated by this research. The paper demonstrates that it is the actual light (of the moon or stars or sun or artificial source) they use to orientate themselves in the horizontal plain BUT that is not navigation. With a "tilt" in their orientation they will fly in circles around the light but this tilt also causes inefficiencies in their actual flight mechanism so will cause erratic directional stability as their flight path rapidly changes their spacial relationship to the light source. Whatever their navigation imperative (heat, cold pheromones,smell, sight, sound) will be affected by this spacial relationship instability.

_xerces_ 3y ago

I think a lot of the comments are also missing the fact that the moon is an unreliable means of navigation due it not always being present the whole night (or at all), changes brightness, moves around the sky and can be covered by cloud. It is unlikely then that insects would specifically evolve to use it as a means of navigation. The paper states that it is the general brightness of the sky, even at night, compared to the ground that is the point of reference. So insect point top side at diffuse bright area and bottom side will be parallel to ground.

conductr 3y ago
It seems to me they are using it, but as you mentioned navigation may not be the purpose. There may be none. It may just be that insects that do this congregate and reproduce thus it’s just a mate finding thing that’s evolved. Since insects often have short lives, I’d guess it also explains why they’re always doing it (they need to mate asap). Might also explain why they don’t go directly to the light but eventually end up there circling it erratically, increased odds of bumping into a mate.
- consp 3y ago
  The paper mentions that the insects enter stall conditions, maybe due to the banked orientations, sometimes and then recover. This would explain erratic behaviour without any mate present.

mihaaly 3y ago

More like using the sun/sky to adjust their attitude of flying. Everyday, not only when moon is visible.