^{The Periodical Cicada’s
Timing
CICADAS, insects resembling
locusts, live on all continents
except Antarctica. Unique to
the northeast of America,
however, are the periodical
cicadas, which have long
fascinated biologists.
Consider: Millions of
periodical cicadas appear
suddenly in the spring for
just a few weeks. During
their short time in the sun,
they shed their juvenile skin,
sing deafeningly, fly,
reproduce, and then die.
Strangely, the next
generation appears either 13
or 17 years later, depending
on the species. What
happens to these insects in
the meantime?
To answer, we need to
understand the periodical
cicada’s unique life cycle.
About a week after
appearing, adult insects mate
and the females lay from 400
to 600 eggs inside tree
twigs. Soon thereafter, the
adults die. Within the next
few weeks, the eggs hatch
and the young nymphs drop
to the earth, burrow into the
soil, and begin a life
underground, where they
suck fluids from the roots of
shrubs or trees for several
years. Either 13 or 17 years
later, the new adult
generation emerges to repeat
the cycle.
According to an article in
Nature magazine, the
complex life cycle of these
cicadas “has confounded
scientists for centuries. . . .
Even now, entomologists are
trying to understand how the
insects’ peculiar life cycles
evolved.” It is an
unprecedented mystery in
the animal kingdom.
What do you think? Could
the periodical cicada’s timing
be the product of evolution?
Or was it designed?}