[HN Gopher] Why flying insects gather at artificial light
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       Why flying insects gather at artificial light
        
       Author : Luc
       Score  : 66 points
       Date   : 2023-04-16 18:11 UTC (4 hours ago)
        
 (HTM) web link (www.biorxiv.org)
 (TXT) w3m dump (www.biorxiv.org)
        
       | zabzonk wrote:
       | i worked in geneva, switzerland for about 6 months, and in the
       | summer literally every streetlight was surrounded by masses of
       | spider webs - they had worked out that this was where small
       | flying creatures were to be found. strangely, i've never seen
       | this anywhere else, at least not in such profusion.
        
       | dvh wrote:
       | Pick a random azimuth you want to go. Keep walking while having
       | sun always at the same position and you'll be walking in the
       | straight line.
       | 
       | 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.
        
         | MauranKilom wrote:
         | This paper specifically provides strong evidence against this
         | explanation:
         | 
         | > We also do not observe logarithmic spirals toward the centre
         | of the light source, a key prediction of celestial compass
         | entrapment.
        
         | mkl wrote:
         | The key finding of the research in this article is that this is
         | not what is happening. See the "Flight path manipulation via
         | light switching" section and the Discussion section.
        
         | canadianfella wrote:
         | [dead]
        
       | h4ch1 wrote:
       | This is very interesting and certainly clears up a long held
       | childhood notion that all insects are attracted to the moon (?)
       | makes no sense, but glad to see research on this.
        
         | sacrosancty wrote:
         | [dead]
        
         | [deleted]
        
       | Qem wrote:
       | Wonder if that explains partially the Windshield Phenomenon.
       | Random lamps attacting flying insects kilometers away just to die
       | surely helps decrease their numbers. See
       | https://en.m.wikipedia.org/wiki/Windshield_phenomenon
        
         | etiam wrote:
         | I just had a light-bulb moment and came back to say something
         | similar.
         | 
         | 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).
        
         | MauranKilom wrote:
         | The paper in question contradicts your hypothesis.
         | 
         | > 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.)
        
           | Qem wrote:
           | That's 4% death rate over a single lamp. Does every lamp they
           | get 85m from have a similar kill probability? The "only one
           | experiment" is also unfortunate. That should be investigated
           | more.
        
         | [deleted]
        
       | tough wrote:
       | Ok so basically insects are trying to get escape velocity from
       | the light source but their DNA makes them really maintain their
       | back from the light, going in circles for ever
        
         | EamonnMR wrote:
         | My quick read of the abstract was something more along the
         | lines of 'insects use the bright sky above and dark ground
         | below to orient themselves, lights create a very different
         | location - dependent up'
        
       | MisterBastahrd wrote:
       | Me living in the DFW 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.
        
         | extasia wrote:
         | What's DFW?
        
           | [deleted]
        
           | SkinTaco wrote:
           | It means fort worth, TX. Like how when people say they're
           | from the NYNJ area, it actually means new jersey
        
           | Stratoscope wrote:
           | Dallas and Fort Worth, Texas
        
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       (page generated 2023-04-16 23:00 UTC)