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Why flying insects gather at artificial light

nature.com

1–10 of 183 posts

Re: Why flying insects gather at artificial light

#2
Cool study, I've got this question before from my 7yo and had no idea :P

If I'm reading it correctly, insects don't fly toward the light, they turn the front of their body toward it. Under natural light, this helps them fly correctly ("maintain proper flight attitude and control"), but with artificial light they end up just constantly flying around the light source?

Re: Why flying insects gather at artificial light

#3

Cool study, I've got this question before from my 7yo and had no idea :P If I'm reading it correctly, insects don't fly toward the light, they turn the front of their body toward it. Under natural light, this helps them fly correctly ("maintain proper flight attitude and control"), but with artificial light they end up just constantly flying around the light source?

Not the front part, the upper/back part. Otherwise, yes.

Re: Why flying insects gather at artificial light

#4

Cool study, I've got this question before from my 7yo and had no idea :P If I'm reading it correctly, insects don't fly toward the light, they turn the front of their body toward it. Under natural light, this helps them fly correctly ("maintain proper flight attitude and control"), but with artificial light they end up just constantly flying around the light source?

> they turn the front of their body toward it

Google says dorsum is "back or top (dorsal) side". Kinda makes sense that they'd assume light means up.

Re: Why flying insects gather at artificial light

#6
> Contrary to the expectation of attraction, insects do not steer directly toward the light. Instead, insects turn their dorsum toward the light, generating flight bouts perpendicular to the source. Under natural sky light, tilting the dorsum towards the brightest visual hemisphere helps maintain proper flight attitude and control. Near artificial sources, however, this highly conserved dorsal-light-response can produce continuous steering around the light and trap an insect.

Re: Why flying insects gather at artificial light

#7
Fascinating that it has nothing to do with desire, which has tended to be our go-to as humans stretching back in particular to mythology and even antiquity (eg Aristotle IIRC: “things fall back to the ground because they have a desire to do so”)

Re: Why flying insects gather at artificial light

#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 gathered in the middle of the room as usual during the summer day. Then I turned on this light just out of curiosity. The flies dispersed within seconds, suddenly perfectly capable of not flying in circles. I don't think it was the heat or the discomfortably bright light just scaring them off. Even this amount wasn't as bright as sunny day. I think more light and more distributed light (not just comming from the direction of the window) fixed their navigational abilities somehow.

Re: Why flying insects gather at artificial light

#10

This seems like a pretty important finding, entymology's version of cracking Fermat's Last Theorem. I wonder if there's a Nobel category for entymology.

I read about this explanation years ago. It's not novel. I don't remember where, though... It might have been from Feynman.
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