Why are moths drawn to light?

Light is a way in which moths/insects find food. Moths/insects think that light leads to a potential food source.
 
Definitively not so. Phototaxis (attraction towards light) in moths is not food related (their food ain't glowing) but it is possible that moths use light (similarly to bees) to navigate.
In bees it is better studied, they use UV radiation from the sun to navigate. If you illuminate bees in a dark room from below they will drop on their back as they assume that the source of UV lights is always "up" (towards the sun).
 
Last edited:
I think its to do with navigation, remember reading it in one of Dawkins books.

http://science.howstuffworks.com/question675.htm

It appears to be due to phototaxis.

Phototaxis is an organism's automatic movement toward or away from light.

Some types of moths are known to migrate, and it's possible that the night sky gives them navigational clues. A moth's up-down orientation might depend in part on the brightness of the sky relative to the ground. Some lepidopterists (moth and butterfly scientists) suggest that moths use the moon as a primary reference point and have the ability to calibrate their flight paths as the Earth's rotation causes the moon to move across the sky. (There is even evidence to support the theory that migrating moths have an internal geomagnetic compass system to guide them in the right direction.) So a moth's attraction to an artificial light or to a fire could be related to orientation, and lead to disorientation -- the moth wasn't "expecting" to actually get to "the moon" (the light source) or to be able to fly above it, so confusion results.
 
Enmos said:
This might be interesting:
http://www.straightdope.com/classics/a5_038.html
Click to expand...

I linked to that below. Never mind.

It's a good article. It is intended for some 14 year old who has a homework project I think, but it's knocked out a theory I had accepted as "the explanation" of this phenomenon for many years.

This a good example of where scientific answers to problems are just working theories, yet they are accepted by everyone and trotted out as "facts".
I was about to do the same.
 
I read that one before I posted here.
It says why a few things aren't why, but it doesn't say why.
Definitely interesting, though.
 
S.A.M. said:
Some types of moths are known to migrate, and it's possible that the night sky gives them navigational clues. A moth's up-down orientation might depend in part on the brightness of the sky relative to the ground. Some lepidopterists (moth and butterfly scientists) suggest that moths use the moon as a primary reference point and have the ability to calibrate their flight paths as the Earth's rotation causes the moon to move across the sky. (There is even evidence to support the theory that migrating moths have an internal geomagnetic compass system to guide them in the right direction.) So a moth's attraction to an artificial light or to a fire could be related to orientation, and lead to disorientation -- the moth wasn't "expecting" to actually get to "the moon" (the light source) or to be able to fly above it, so confusion results.
Click to expand...

That's the best explanation I have heard so far, though I am not sure what the moon moving across the sky has to do with anything.
I hardly think moths have an understanding of lunar positions and phases and can judge their position on the ground based on the the moon.
"Oh, the moon is in Virgo, facing Ursa Major, I must be in Jersey City. I know a great Indian restaraunt here, follow me!" :)
 
Apparently it has been proved that moths use moon light to navigate, since when their eyes are covered, they lose their way.
 
S.A.M. said:
I think its to do with navigation, remember reading it in one of Dawkins books.

http://science.howstuffworks.com/question675.htm

It appears to be due to phototaxis.

Phototaxis is an organism's automatic movement toward or away from light.

Some types of moths are known to migrate, and it's possible that the night sky gives them navigational clues. A moth's up-down orientation might depend in part on the brightness of the sky relative to the ground. Some lepidopterists (moth and butterfly scientists) suggest that moths use the moon as a primary reference point and have the ability to calibrate their flight paths as the Earth's rotation causes the moon to move across the sky. (There is even evidence to support the theory that migrating moths have an internal geomagnetic compass system to guide them in the right direction.) So a moth's attraction to an artificial light or to a fire could be related to orientation, and lead to disorientation -- the moth wasn't "expecting" to actually get to "the moon" (the light source) or to be able to fly above it, so confusion results.
Click to expand...

Birds migrate and pigeons return home using similar astronomical information.
 
Though physical landmarks are used in ordinary day to day flights within a give area these are of little use during migration across previously unknown habitats. Instead moths use either the earths magnetic field or the light of the moon and stars or both to navigate. Experiments suggest that the Large Yellow Underwing can detect and respond to the earths magnetic field, though the mechanism behind the detection is as yet unknown. Other work has shown that they respond to the position of the sun and the moon, even making corrections for the changing position of the moon with time to keep their course straight. How they know or why they choose a particular direction is unknown.

http://www.earthlife.net/insects/lepidop2.html

For some reason I don't know the code words that will avail me of the papers themselves.
 
one_raven said:
That's the best explanation I have heard so far, though I am not sure what the moon moving across the sky has to do with anything.
I hardly think moths have an understanding of lunar positions and phases and can judge their position on the ground based on the the moon.
"Oh, the moon is in Virgo, facing Ursa Major, I must be in Jersey City. I know a great Indian restaraunt here, follow me!" :)
Click to expand...

We do similar things ourselves mistaking visual clues in the countryside when we set out on journeys for places which appear an hours walk away. After half a day, they still look an hours walk away.

Same thing with constellations. We think stars in constellations are close together, but they may be further away from each other than from stars in a totally different part of the sky.

If we can do this with our big brains, what hope has a moth got?
 
I'd think moths are attracted to bright lights because they want to know what it is. Just as people are attracted to bright shinny things also.
 
S.A.M. said:
Apparently it has been proved that moths use moon light to navigate, since when their eyes are covered, they lose their way.
Click to expand...

LOL
You will have to excuse me for this but, do you lose you way when your eyes are covered ? Yes ? Do you also hang around streetlights at night then ? Or smash yourself into a cars headlights ? :p
 
Enmos said:
LOL
You will have to excuse me for this but, do you lose you way when your eyes are covered ? Yes ? Do you also hang around streetlights at night then ? Or smash yourself into a cars headlights ? :p
Click to expand...

You mean you normally walk around with your eyes covered?:)

Another theory:

University of North Carolina medical technologist Henry Hsiao put forth an interesting theory concerning the Mach Band, an optical illusion well known to painters, where a harsh line between darkness and light produces an apparition of two bands, one light and one dark. Hsiao asserted that moths fly into the dark Mach band in an attempt to evade the light, which puts them into orbit around a terrestrial light source—a marvelously creative explanation. To my mind, the most logical hypothesis posits that moths fly perpendicular to light radiation. Under a normal night sky, this keeps them flying horizontally, but will cause them to circle about a candle if that is the brightest light source.
Click to expand...

http://rigorvitae.blogspot.com/2006/03/moth-in-night-sky.html
 
Last edited:
You must log in or register to reply here.
Back
Top