Finding something good in
everything takes work.
For instance, it requires a colossal
imagination stretch to find positives in the forest tent caterpillar onslaught
chewing parts of Ontario.
There are no reports of wide
scale infestations in Haliburton, however serious outbreaks have been reported northwest
of the county. The Sudbury-Manitoulin Island region seems to be the centre of
an infestation that stretches west to Sault Ste. Marie and east into the Ottawa
Valley.
The creepy critters have
been crawling all over Sudbury’s landmark Big Nickel, the nine-metre tall
replica of a 1951 five-cent piece. In some places they are covering outdoor
furniture, cars and house walls.
Caterpillar infestations are
nothing new. They aren’t caused by climate change, rising oceans or anything
like that. Folks back in the late 1700s reported witnessing them.
There are numerous species
of caterpillars but the ones we most often see are the forest tent caterpillar
and its close cousin the eastern tent caterpillar. The tent caterpillar has
white or yellow spots on its back while the eastern tent caterpillar has a
solid white or yellowish back stripe.
These worms follow
bust-to-boom-to bust cycles, reaching peak numbers every 10 to 12 years, then
dying off before beginning a new cycle.
Peak infestations see
billions of caterpillars chewing the leaves off thousands of acres of forest. Defoliation
can be severe with trees left with nothing but naked limbs. The preferred
leaves of the tent caterpillar are poplar and birch although they also are
attracted to hardwoods.
Even peak infestations do
not seriously damage healthy trees. Tree trunks hold enough nutrients to keep
themselves going long enough to produce a new crop of leaves.
However, armies of caterpillars
have been known to delay highway and rail traffic when squished bodies make
pavement and rails dangerously slippery. Caterpillars also have been known to crawl
along power lines, causing outages.
They can be a major nuisance
but pose no threats to human health.
Tent caterpillars emerge in
spring and go on a feeding frenzy until late June or early July when they transform
into flying moths. The moths lay egg masses on tree twigs the thickness of a
pencil. The egg sacs remain there until next spring when new caterpillar populations
emerge.
During peak infestations
masses of caterpillars actually can be heard munching leaves.
Anything that eats that much
has to go the bathroom. And, caterpillars go to the bathroom a lot.
Walking through a forest
where caterpillars are at work you might hear what sounds like light rainfall. It is not rain. It is
caterpillar poop, little pieces the size of pepper flecks, falling from the
trees.
Scientists have positive
thoughts about all this. Caterpillar excrement is rich in protein and nitrogen,
they say, so it is good fertilizer when it falls to the forest floor.
Also, folks who study these
things say that when caterpillars defoliate a forest they create openings that
let sunlight into lower areas, creating healthier conditions for smaller plants.
Caterpillars also provide
food for birds and to a lesser extent, squirrels, chipmunks, raccoons and mice.
Fish are said to gorge on them when they fall into lakes or streams. However,
as caterpillars grow, the hairs on their sides stiffen and make them less palatable,
and less digestible.
That doesn’t seem to bother
bears. The North American Bear Centre in Minnesota reports that a black bear
consumes roughly eight to 10 kilograms of caterpillars a day. Considering that
a fully developed caterpillar weighs only one-half gram, that’s a lot of
caterpillars.
The centre said one bear
consumed 25,192 caterpillars in one day. How could any researcher come to that
exact count? Certainly not by watching the bear stuffing them into its mouth.
It turns out that caterpillar
skins pass through a bear’s digestive system intact and can be found in their
scat. A researcher tracked one bear for three 24-hour periods, collected all of
its 73 droppings and counted the caterpillar skins in the poop.
So, as ugly and unwanted as
they are when they come in masses, caterpillars do have their positives. They
provide food for other wildlife and work for researchers willing to poke their
fingers into stuff most of us gladly sidestep.
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