Why Moths are Obsessed with Lamps | National Geographic

the story of the lamp in the moth is one
of fatal attraction the theory is that
these primarily nocturnal insects have
evolved to travel by the light of the
moon and the stars
this way of travel is called transverse
orientation an easy way to think about
transverse orientation is to imagine a
sailor traveling in the direction of the
North Star in theory moths
similarly follow the light source at a
precise position and a precise angle to
their bodies this is how moths would
navigate for millions of years by the
light of the moon
what moth evolution couldn’t account for
was the proliferation of constant
electric light in our modern world when
Thomas Edison patented the light bulb on
January 27th 1880 it was a bad day in
moth history these light bulbs began to
act as artificial moons confusing moths
and overwhelming their senses since
moths are accustomed to orienting to
distant light sources they can be easily
disoriented when a closer light source
like a porch lamp comes into view when
there are really bright lights or
ultraviolet lights the draw becomes
almost irresistible and insects respond
to ultraviolet light far more than any
other wavelength at night an ultraviolet
source is a super stimulant to a moth
these artificial moons make moths easy
targets for predators like birds bats
and many other animals while much is
still to be learned about moth behavior
one thing is certain the moths obsession
with lamps often proves to be a fatal one