Page 23 - How It Works - Book Of Amazing Answers To Curious Questions, Volume 05-15

Environment

Between 60
Bet w ee n 6 0
million and 1

billion monarchs

undertake an
incredible winter

migration

Take off!
The monarch fi nally
spreads its wings and

takes flight, ready to begin
the cycle all over again.
Flight
preparation
A newly emerged
butterfl y waits
about an hour for
its wings to dry
completely and
become fully
airworthy.

Fluttering on the brink Milkweed plants
Revered or not, the monarch is under threat. are essential to
Emergence Populations have fallen drastically since the Nineties the monarch’s
survival
The adult due to environmental degradation and human
monarch pushes agricultural practices.
its way out, In Mexico, habitat loss from illegal logging, plus a
grabbing on to the string of natural disasters have reduced the
exoskeleton; availability of suitable overwintering grounds. In the
within minutes, US, herbicides used by farmers have decimated the
its tiny folded
wings grow to monarchs’ vital host milkweed plants.
full size. Experts are also concerned about how global
warming will affect rainfall patterns and alter the
timing of the migration. Monarchs can’t fl y unless
their body temperature is at least 30 degrees Celsius
(86 degrees Fahrenheit), so cold snaps in Mexico –
one of the predicted effects of climate change –
Final stages could spell disaster for the species. According to the
The green pupa US Fish and Wildlife Service: “Unless we act now to
becomes transparent © Corbis; Thinkstock
one day before the adult help the monarch, this amazing animal could
is ready to emerge. disappear in our lifetime.”

How It Works 23