> 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.
> 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 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.
If I understand correctly part of the explanation is that when they're flying horizontally they need to compensate for gravity by pushing up, kind of like what planes do. If you put them in a place where there's no gravity with a light floating in the middle of a room they'd orbit the light while also getting closer as they're trying to compensate for gravity, and when you put gravity back I guess that produces the weird orbiting we observe.
Haven't seen flying insects since last summer but if I think they kind of lose altitude the closer they get to the light source, which would be when their torso is less horizontally oriented.
Also this is just a guess but I imagine the closer they're to the light source and the larger the contrast between bright and dark is, the stronger is their tendency to get locked into the orbiting path as opposed to flying randomly.
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.