light pollution

Chris Conlan conlan at adnc.com
Thu Sep 18 03:18:04 EDT 1997


While this probably is a topic full of debate let me toss in some thoughts
and observations.  I sincerely doubt that light pollution is the sole
reason or even a large reason for a lack of moths in urban areas.  Sure
I've seen my share of moths get eaten by birds, bats and other insects at
lights but experience would lead me to believe that what you see fluttering
around the lights is only a small sample of what's out there.  It's also
possible that in urban areas with lots of artificial lighting the selective
pressure is very heavy on the local populations leading to fewer
individuals attracted to light.  Here are some examples of my reasoning:
1.  I live on a canyon in an urban area.  Both sides of the canyon are
developed with plenty of lights to light up both rims.  Being the die-hard
entomologist I run a UV light facing into the canyon most nights.  There
are a number of moths that I have never taken at my lights but I have found
larvae either in my yard or very close by.  One species in particular
(Smerinthus cerisyi) I seem to find larvae almost every year on the willows
in my yard and I can call in wild males whenever I have a female.  However,
I have never captured a single individual at my lights in the 8 years I
have lived here!  I do see this moth at my lights when I collect in rural
areas a short drive from my home.  Somebody said nearly the same thing in
an earlier post about polyphemus moths and ceanothus silk moths.

2.  On numerous occasions while collecting I have seen moths flying around
and nectaring near my lights.  They were not in the least bit attracted to
the light and went about their business as if the light was not even there.
It's also common to see insects fly to the collecting lights for a brief
moment and then fly off again never to return.

Basically, I would focus my concerns more on the habitat loss, pollution
and pesticide spraying that comes with urbanization.  Maybe the astronomers
have more to complain about?

Chris
conlan at adnc.com




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