206ENVIRONMENT: WOOLLY BEAR CATERPILLARS
Miss Dutton wasn’t alone in
her championing of the woolly
worms, first identified by James
Edward Smith in 1797. There
is a landmark festival held in
Vermillion, Ohio, featuring
a parade and a woolly worm
costume contest for humans and
pets. And every October since
1977, a crowd has gathered in
Banner Elk, North Carolina,
for the annual caterpillar race
and alleged winter forecast
prediction. Because the woolly
knows best!
Folklore has long revolved
around the 13 distinct segments
of the caterpillar. The amount
of black on each end obviously
indicated the length and
bitterness of the approaching
winter. An abundance of black
suggested a more severe winter,
while a wider, rusty midriff held
promise for a mild winter.
Come spring, regardless
of what the rusty and black
segments have dictated, the
re-emerged woolly bear feeds
briefly and then sets about
creating a rather industrious
oblong cocoon. If you find a
taupe-coloured cocoon that looks
like an oversized cotton swab,
it’s probably an Isabella tiger
moth in the making. There are
two generations, or broods, that
emerge in May and August. The
late-summer brood is forced to
endure the winter extremes (a
cryoprotectant in the caterpillar
tissue allows them to essentially
freeze solid and thaw) before
transforming and taking flight.
Tiger moths (and their
larvae-form woolly bear selves)
are abundant in the southern
third of Canada, northern
Mexico and the United States.
The mustard yellow and orange
forewings with black dots are
easy to spot once you know what
you’re looking for. The males
display more of an orange tint,
while females appear rosier.
The hindwings of both sexes are
pinker with grey dots and only
visible when the moth’s wings are
spread and flat.
The woolly bear may win
resiliency awards, but the Arctic
woolly bear, found in Greenland
and the Canadian High Arctic,
takes home the hardware. This
species can experience a full
caterpillar life cycle of 15 years.
With four years between moults,
the Arctic woolly remains in
larval stage for most of its life.
Thanks to diapause, a
mechanism that delays
development, the caterpillar
can adopt a dormant state and
endure temperatures of –70°C
(–94°F). This same mechanism
allows many insects to survive
droughts, temperature extremes
and reduced food supply.
And, I assure you, we’re not
trying to pull the woolly over your
eyes! It would be great to have
a little built-in cryoprotectant
for this upcoming winter,
wouldn’t it? H