Every year, fragile monarch butterflies fly more than a
thousand miles, from Canada to their winter home in Mexico.
They stop along the way to eat milkweed, one of their
favorite foods. Until recently, no one knew how they
navigated such great distances, but now scientists have
discovered that they carry a "solar compass" inside their
tiny brains, which picks up ultraviolet light?the light
range that humans cannot see.
Scientists have long suspected that monarchs use the sun to
guide them, but since the sun moves across the sky as the
day progresses, they didn't know how the insects managed to
keep flying due south. This question has been answered by
the discovery of a brain link from their eyes, which detect
ultraviolet light, to the part of their brains which does
the actual navigation. When researchers placed a filter that
screened out UV light over the butterflies' light source,
the insects became confused and started flying in circles.
In recent years, unknowncountry.com has posted stories about
how the monarch butterfly forest in Mexico?where all
monarchs go in the winter?is being cut down and destroyed by
local farmers, who resent not being able to grow crops on
the land because it?s a butterfly sanctuary. Tourism may
save this habitat, as long as people are careful not to
disturb the insects, since the sight is incredible:
literally thousands of orange butterflies clinging to tree
trunks.
Many people are not aware that monarchs navigate every year,
since most other butterflies live only a season and die in
the winter. A group of monarchs high in the sky are not
likely to be noticed?unlike, for instance, a flock of
honking geese. When they stop to feed along the way, in
places like Southwest Texas, you can see flocks of these
orange beauties, close to the ground, which often end up
flattened on drivers? windshields, along with other insects.
Which end-time prophecies hold up and which do not? Now a
careful reporter has taken a serious look at the history of
terrifying prognostications.
This book
will free you from a lot of worries...but not ALL of them!
Art credit: http://www.freeimages.co.uk
