I wonder if spiders have fights over who gets to build their net next to that big, bright lantern. Those must be prime real estate for them.
Some (or most) spiders are territorial and yes, they do fight for hunting ground.
Why flying insects gather at artificial light
61–70 of 183 posts
Re: Why flying insects gather at artificial light
#62So 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
>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.
Re: Why flying insects gather at artificial light
#63Earlier 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…
> 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 cha…
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)”
Re: Why flying insects gather at artificial light
#64Well one other aspect of this research springs to mind.
Most "bug zapper" design are wrong. It should consist of a light source and a single grid perpendicular to the light source rather than surrounding the light source.
The light source should also be constantly varying to ensure the insects' tilt (and hence their circling behavior) will also change the radius of their circles.
Re: Why flying insects gather at artificial light
#65Earlier quoted context omitted.
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.
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.
Re: Why flying insects gather at artificial light
#66I wonder if spiders have fights over who gets to build their net next to that big, bright lantern. Those must be prime real estate for them.
Some (or most) spiders are territorial and yes, they do fight for hunting ground.
Makes sense. Thanks for clearing that up! I really do learn something new every day.
Re: Why flying insects gather at artificial light
#67 And there's this moth outside my kitchen door
She's bonkers for that bare bulb
Flying round in circles
Bashing in her exoskull
And out in the woods she navigates fine by the moon
But get her around a light bulb and she's doomed
She is trying to evolve
She's just trying to evolve
Gunnin for high score in the land of dreams
Morbid bluish-white consumers ogling luminous screens
On the trail of forgetting
Cruising without a care
The jet set won't abide by that pesky jet lag
And our lives boil down to an hour or two
When someone pulls a camera out of a bag
And i am trying to evolve
Trying to evolveRe: Why flying insects gather at artificial light
#68previous discussion https://news.ycombinator.com/item?id=35592654 128 comments
Re: Why flying insects gather at artificial light
#69It’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…
Interesting. I sometimes wonder how they end up near the lights: there wouldn't seem to be a light source at night for most of their evolution. Maybe they used the moon in the background.
But is it correct to assume that, if something is naturally possible (e.g., bioluminescence), and provides significant evolutionary advantage, the species will evolve it?
If so, why are we the only intelligent ones (so far)? Why didn't chimpanzees, sharing a common ancestor with us 7 million years ago, evolve intelligence?
Re: Why flying insects gather at artificial light
#70What about the color? I know it is slightly orthogonal, but the article says: "This is true even at night, especially at short wavelengths (I always wondered: isn't there a light color that we human see and that minimizes the impact on the insects? Say if we only used red light in the cities, would it help?