© Janet Davis
It was a glorious
morning in early September. I decided to
set up my tripod and camera in a meadow and focus only on what I could spy
within arm’s reach of where I stood. With the naked eye, all I saw near me were
wildflowers like goldenrod and aster, but as I focused on the blossoms with my closeup lens, I realized there were all kinds of insects –
some microscopic, some tiny, others quite large.
I
zoomed in on one stunning, yellow-striped, black insect patiently working the
tiny flowers of goldenrod. With its
coloring, I initially took it to be a wasp or hornet; it was only after I
studied it closely that I realized it had the hard shell typical of beetles.
Intrigued,
I went home and thumbed through my National
Audubon Society Field Guide to North American Insects & Spiders. I was reminded that beetles comprise Coleoptera, the largest family in the animal
kingdom with some 300,000 species worldwide.
And I learned that the hard shell is actually a pair of forewings or
“elytra” that meet in the middle when the insect is at rest and open when in
flight. I read that beetles go through a
2-stage metamorphosis with the larvae called grubs (like the root-chomping
grubs of June bugs and Japanese beetles that ruin lawns).
When I found
the photo of my beautiful pin-up, I was even more intrigued. It was the locust borer beetle. “Elongate, stout, velvety black with
gold-yellow bars on head, pronotum and elytra,
including ‘W’ in middle of body.” Its
habitat was listed as woods with black locust trees in eastern Canada and the U.S.
“Adult eats goldenrod pollen and nectar,” continued Audubon. “Larva eats sapwood of black locust.”
I
mused on how this gorgeous but destructive insect had evolved a need for the
wood of only one tree, Robinia pseudoacacia,
and how that was reflected in its own Latin name, Megacyllene robiniae. And I thought about how both tree and
predator honour a 16th Century Frenchman
named Jean Robin who, as head gardener for Henry IV and Louis XIII, had been
among the first Europeans to grow seeds of North American plants collected by
early explorers. I even remembered
seeing a sign in the Jardin des Plantes, where Robin
had toiled, that pointed out a gnarled black locust as the oldest tree in Paris.
Putting
down my Audubon, I turned to my new edition of A
Natural History of Trees of Eastern and Central North America, a
wonderful book, originally published in 1948, by tree historian Donald Culross Peattie. He waxed eloquent on the black locust. “Under any name, this tree is impressive,
when it grows to a soldierly 80 feet, the trunk 3 or 4 feet thick. When the Locust flowers, in late spring, its pendant spikes of
honey-sweet blossoms look as though some white wistaria
had climbed in the stalwart tree and let down fragrant tassels of bloom.”
But
Peattie went on to describe why, with the straight
trunk of the black locust and legendary hardness and durability of the wood
(“taking White Oak as the standard of 100 per cent, Black Locust has a durability
of 250 per cent…”), it could never be useful to the lumber industry. “The chief reason is that the locust borer
beetle is so ruinous in many regions that Black Locust is too seldom found in
sound condition.”
I
thought about the beetle’s wasp-like markings, a highly-evolved defence mechanism called “mimicry” that I’d read about in
Charles Darwin’s On
The Origin of Species. Over the eons, an animal adopts
characteristics similar to other species in order to deceive predators that
would normally find it a tasty meal, but steer clear if they think it might
pack a sting or toxin.
And
as I put away my books, a thought occurred.
A little knowledge is a dangerously wonderful thing.
Adapted from a
column that appeared originally in the Toronto Sun.