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

Stanley A. Gorodenski stanlep at gateway.net
Wed Dec 29 23:28:38 EST 1999

Thanks for the message.  I belong to the International Dark Sky
Association whose purpose is to preserve our dark skies for astronomical
purposes and for our and our children's esthetic enjoyment by
eliminating bad and unnecessary outdoor lighting.  This organization
collects information on adverse biological effects of light pollution
(light that goes up in the air and is otherwise wasted).  I will forward
your message on the potentially adverse effect on moth egg laying cycles
to this organization.

Stan Gorodenski

MyName wrote:
> I've been meaning to post this for about 10 years now, but for some reason I
> always forget to share it on the newsgroups. I've told quite a few people but
> have never posted this publicly, til now.
> I'd like to set the record straight. Moths do NOT travel towards lights for some
> navigational purposes. Moths do NOT travel towards lights for some reproductive
> or food source seeking purposes.  Tear out all those useless entries in your
> science books. And for heaven's sake PLEASE stop teaching these WRONG answers to
> any students or children you might know.
> Why do they travel towards lights? Simple (and only answer) -- They want to
> sleep.  (Now _that_ is an answer I can relate to. :-)
> I used to attract moths to my screened window using a U.V. lamp so that I might
> photograph them.  I would wait until they had settled down to a resting state,
> then very carefully opened the screen, picked them up, brought them inside,
> photographed them, then released them outdoors when done.  If I jostled them too
> much they immediately started to shiver to raise their muscle temperatures to
> ready them for flight. I would stop what I was doing, and wait for them to go
> back into a sleep-state by holding them near a bright light then continue on
> with my photography.
> Now you ask, why would they want to sleep? Simple answer: When they are in a
> sleep cycle they are the most safe from predators.  I've noticed that this need
> to remain camouflaged and still is even more powerful than their need to
> reproduce.  Many (nearly all) species will even forgo finding appropriate food
> plants to lay their eggs on. Instead they will lay their eggs right on my window
> screen if I leave the U.V. light on for a period of days.  Content to stay
> there, totally asleep, their eventual egg-laying cycle taking over while
> sleeping.
> This finding of mine has some overwhelming consequences.  The main one: Light
> pollution may be doing more harm than we ever thought possible. How many
> species' (not only moths) mating and egg-laying cycles are being disrupted by
> light pollution? Could this account for some of the decline in amphibians and
> other insectivore species world-wide? You can take further possible consequences
> from there. In order to save our ecosystems it might one day be a mandate to
> turn off your outdoor lights at night.
> In any case, I have to lay to rest some of the outmoded and utterly ridiculous
> myths of why moths go to lights. Hasn't anybody ever stopped to realise that a
> moth travelling in a straight line by navigation using moon-light or star-light
> (the usual old theory) would serve ZERO purpose to a moth?  Why would travelling
> in a straight line afford them more food sources or the chance to find a mate?
> That's just silly. There are no straight lines in nature. Their mates are not
> lined up like bottles on a fence rail nor are their food supplies.
> (As with all my discoveries in life, I post this anonymously. The same as I did
> on a local BBS back in 1980 with my answer to the "chicken vs. egg" koan.  Oh,
> you've not heard that answer? Simple: The only place that mutation can take
> place is in the egg.  Therefore, something "not quite a chicken" laid an egg.
> That egg, by chance, now had the genetic code to be a "real chicken".  The "REAL
> chicken" egg came first.)
> Too bad I don't have some academic-shingle sig to tack onto this post to make my
> finding more acceptable to your linear minds. But I'm just a simple man, a
> naturalist, watching nature my whole life and seeing how she behaves.  This is
> just one more correct page in the book of "The Nature of Nature" that I have
> come to know so well.
> We now return you back to your learned scientists and all the mistakes they have
> made and taught you in school, lo these many years ...
> "What does education often do? It makes a straight-cut ditch of a free,
> meandering brook."  --  Henry David Thoreau

If people knew how hard I had to work to gain my mastery, it wouldn't
seem wonderful at all.  -- Michelangelo

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