Why Are Moths Attracted To Lights? -- The Real Answer

[Neil Jones]

In article <386D0D0B.957E8226 at gate.net> viceroy at gate.net "Anne Kilmer" writes:

> For diurnal creatures, light is the way out. This is why the dragonflies
> bumble about in my skylight rather than going out the door. Of course,
> up is also the way out, which is why so many butterflies die in
> captivity.

Of course that is fairly obvious. However why is it that both moths
and butterflies fly _around_ the light sources spiraling inwards.
I have seen this many times with butterflies that become active after
dark and that are released indoors. They fly around the light bulb.
Moths do the same thing.


One of the published theories states that moths are actually flying
into an area of perceived darkness around the light source.
If I recall correctly the suggestion is that powerful light sources
confuse the insect's visual system to produce this effect. However
this falls apart when you suggest the same thing happens with
diurnal butterflies.
It seems to me that none of the theories is capable of explaining 
all the phenomena that we observe.

> Noname's theory is interesting; I just think it needs more investigation
> before the Night Sky people run with it. 
> Moths are notoriously casual about where they drop their eggs. 
> Any idea starts with one person, of course, but then we look at
> replication. 
> Light pollution is indeed a horrible problem, and I certainly hope we
> solve it. 
> There is a huge spotlight on the little school next to my house in
> Ireland, and perhaps I should ask ... does it really have to burn all
> night? There should be stars. 
> Cheers
> Anne Kilmer
> 
> Neil Jones wrote:
> > 
> > In article <7hml6sgbekkft9clfn74t2trnsgrt06qm0 at 4ax.com>
> >            nospam at noaddress.com "MyName" writes:
> > 
> > If this theory is correct why do butterflies also fly to light?
> > If you release a butterfly indoors at night it will tend to fly around
> > the light source just like a moth does.
> > It is also not unknown to find butterflies in moth traps.
> >
> 
> 

-- 
Neil Jones- Neil at nwjones.demon.co.uk http://www.nwjones.demon.co.uk/
"At some point I had to stand up and be counted. Who speaks for the
butterflies?" Andrew Lees - The quotation on his memorial at Crymlyn Bog
National Nature Reserve