LETTER FROM BOBOLINK FARM
PILGRIM’S PROGRESS
By Barbara Tatham Johnson
If my husband had not gone to pick a ripe melon from the garden patch one
morning this week and told me he had seen a monarch butterfly, I might have
missed the one monarch sighting about the place this season.
The monarch among the melons is a male, I note, from the black dots on the
vein of each hindwing—scent patches to advertise his presence to female
monarchs. He emerged from his pupal case, called a chrysalis, early this
morning. Shaded by the umbrella of melon leaves, he has almost completed the
task of pumping body fluids into his brand new wings. The lower edges of the hindwings have a slightly crumpled look compared to the crispness of the
full spread of orange and black extended to either side of his body.
The beauty of a fresh, unblemished creature is stunning and difficult to
describe. A blossom catching the sunlight moments after unfurling, a
salamander larva twisting free of the globe that was her egg beginning, a
butterfly displaying colorful wings that seem scaled with velvet are chance
and therefore precious sights.
This monarch’s deep orange wings, edged and veined in black, dotted with
white, splashed in a few places on the upper wings with creamy ochre, seem
all the more gorgeous to me because I have not seen a newly emerged monarch
in years. I saw no monarchs in 2002 and only three in 2003. All were distant
dancers, flashes of orange across the meadow. With summer coming to an end,
I may see no more this year, for this butterfly is a member of the last
brood or generation of monarchs in Maine this summer. Emerging in late
August and early September, these monarchs are programmed by shorter
daylight hours and the lower angle of the sun to develop into individuals in
a state of reproductive diapause. They have undeveloped sexual organs and no
interest in mating. They feel a strong urge to follow their natural sun and
geomagnetic compasses in southward flight. They want to fill up on all the
nectar they can find, add great amounts of body fat to fuel their journey
and help them survive the winter. This is the traveling generation of
monarchs migrating to wintering sites thousands of miles to the south.
Canadian entomologist Fred Urquhart perfected a way to attach tiny
lightweight identification tags to the wings of migrating monarchs.
Information about their movement south in autumn and north in spring over
the years provides amazing insights on the intricacies of living a pilgrim’s
life.
The butterflies can travel from ten to thirty miles per hour and as far as
eighty miles a day. They may fly at heights of one hundred and fifty feet or
more, and they roost in trees at night. Whenever possible, they sip that
fattening nectar.
The migration routes of the monarch butterfly population are pretty well
known. Western monarchs, most from the valleys of the Great Basin, winter in
California’s Monterey Peninsula. Populations on the eastern seaboard of
North America make their way to Florida, the Caribbean Islands, Yucatán, and
Central America. The exact locations of overwintering sites of this
population remain undiscovered.
The greater population of eastern monarchs migrates to scattered forest
patches of oyamel (a type of Mexican fir tree), pine, and cypress growing at
elevations of 9,000 to 11,000 feet in mountains west of Mexico City. Here,
hundreds of thousands of monarchs hang in a semidormant state, forming huge
tree-blanketing masses until strengthening sunlight and warmer weather in
February trigger an awakening and the development of their sex organs. The
butterflies mate. The males die. The females, body fat depleted, fly
northward to nectar at spring flowers and lay their eggs on sprouting
milkweed plants in northern Mexico and the American southwest. The emerging
caterpillars develop in seven weeks or so into adults who mate, fly
northward some distance, and repeat the process. As many as four cycles may
occur before monarch butterflies reach their northern range in Canada. A
very few individuals, tagged the previous autumn before leaving on the
southward migration, return to the area where they began life.
Weather and just about every creature that is not a butterfly conspire to
interrupt or end this awesome quest. In 2002, an estimated 270 million
monarch butterflies froze in their overwintering colonies in the Mexican
mountains when drenching rains were followed immediately by freezing
temperatures.
In early spring, large numbers of egg-laden monarchs are captured and
transported north to butterfly farms with acres of cultivated milkweed
plants where the butterflies are set free to lay eggs. The resulting
caterpillars are gathered and raised in containers until they form
chrysalises that are then collected and shipped to museum butterfly rooms,
schools, and private butterfly enthusiasts. Farming monarchs is a profitable
business, earning owners hundreds of thousands of dollars. Although monarch
butterflies live and reproduce in these operations, scientists are concerned
about inappropriate genetic mixing and confusion in the migration responses
of the monarchs.
Corn, genetically engineered to contain the genes of a caterpillar killing
bacteria, Bt, is grown on increasing acreages each year. Corn borers are
eliminated, but the corn pollen, which can blow for hundreds of feet onto
adjacent land, coats other plants, including milkweed, with Bt. Feeding
monarch caterpillars die as quickly as corn borers.
The oyamel forests of Mexico disappear as logging operations increase in
spite of laws passed by recent Mexican governments. Even the tags that
scientists put on monarch wings to track their movements can be fatal. Birds
that usually shun the orange and black butterflies because these colors
advertise the bitter toxins of the monarchs’ milkweed diet, interpret the
pattern of multicolored tags as that of a possibly palatable butterfly and
snap them up. The birds spit them right out again, but the monarchs lose.
Each spring monarchs return to Maine, but they are less of a presence on our
place. Each sighting is treasured—all the more if the meeting is up close
and prolonged. The monarch in the melon patch moves a bit to a spot where he
can exercise his wings. Slowly he raises and lowers them for the first time.
A light breeze brings lift, and he tips and tilts for balance, not quite
ready for flight.
I am tempted to burden delicate creatures who live lives of dazzle and
mystery with wonderful powers. The monarchs’ urge to cover vast distances
and brave every imaginable threat puzzles and amazes me. I cannot imagine
what this must be like—existing as a voracious worm, repackaging myself
while stuffed inside a sort of duffel bag, then pushing my way out one day
into an immense space of sunshine and moving air with the overpowering need
(and the means to carry it out) to fly in a specific direction while craving
all the nectar I can find.
Suddenly, in the midst of his balancing act, the monarch’s wings catch the
moving air just right. He flutters aloft, rising over my head and out across
the meadow. I hope he spies the big circle of purple phlox blooming in my
front yard and stops to enjoy his first sweet drink, but the breeze and his
insect ways whisk him farther away until, as a pinprick of bright movement
far across the grass tops, he disappears.
“Good luck, all the way!” I whisper.
