TIME OF THE
MONARCH
By Sandra Harper
Photo by Barbara Wilder
In Texas, migrating Monarchs will find fall blooming native flowers such as frostwood in their search for life-sustaining nectar.
F
or most ordinary mortals, the
butterfly that captures our
imagination is the Monarch.
True, the butterfly is rather large, with a
3 to 5 inch wingspan making it easy to
spot. And its orange wings – thickly
veined in black and edged in white polka
dots – give off quite a show. But it is the
story of the Monarch’s nearly 3,000-
mile migration that tugs at our hearts
and bolsters our spirits with imaginings
of how the tiniest amongst us can over-
come an unthinkable challenge.
Butterflies and moths belong to the
Lepidoptera order of insects, the scaly-
winged ones. The butterfly might be a
moth that left its night-bound life behind
for a daylight existence to co-evolve with
flowers during the Cretaceous Period.
The Monarch, Danaus plexippus, is one of
the brush-footed milkweed butterflies in
the Nymphalidae family. Their small
brushy forelegs are kept tucked up under
their thorax. These lovelies are tropical
butterflies. As glaciers retreated after the
4
Ice Age, they traveled further and fur-
ther north following their host plant, the
milkweed, as far as Canada.
The only plant the Monarch larvae
feed on is the milkweed. The females lay
their eggs on the underside of the plant’s
leaves. Its common name comes from the
milky latex sap it oozes when a leaf is bro-
ken off. An ancient medicinal plant, milk-
weed takes its scientific name, Asklepius,
from the Greek god of healing.
The cardiac glycosides in the milk-
weed, used by plant medicine makers to
reduce the inflammation of mucous
membranes and to treat heart ailments,
are found stored in the bodies of the
Monarch caterpillar and butterfly.
These chemicals give the insects a nox-
ious taste and protect them from most
predators. The bright pumpkin color of
the butterfly might be a warning to a
hungry hunter saying, “You don’t want
to eat me. I’ll make you sick.”
When the summer milkweeds yellow
and tufts of their silky seeds parachute
Cenizo
Third Quarter 2010
through the increasingly cool air, the last
Monarch of the year to metamorphose
splits open its chrysalid. Clinging to the
transparent remnants of the chrysalis,
the butterfly inflates its crumpled wet
wings, pumping them full of
hemolymph, then hangs upside down
for several hours waiting for the wings to
dry and harden before taking flight.
Unlike the Monarchs of spring and
summer, the fall brood will not mature
sexually right away but will remain pre-
pubescent during the grueling migration
south and the months spent in the win-
tering grounds.
The eastern population of fall
migrating Monarchs spends its winters
in the fir-covered volcanic mountains of
central Mexico. Sixty-foot tall forests of
the oyamel fir, moist and cool from
mountaintop clouds, shelter the butterfly
clusters. As the coldest months of the
year pass into warmer ones, millions of
Monarchs fully wake from their torpid
state more sexually developed. In his
book, Chasing Monarchs, the naturalist
Robert Michael Pyle writes intriguingly,
“the ‘courtship’ following the winter
dormancy can only be considered as
ravishment.”
“The male simply attacks the female
on the wing, drives her to the ground,
and wrestles with her. He will maneuver
the female onto her back, wings spread,
and cover her – a face-to-face embrace
I’ve never seen among other butterflies.
In a couple of minutes he will achieve
copulation by enfolding the tip of her
abdomen within the handlike claspers of
his own rear end and inserting his
aedeagus. Then he will fly straight up,
carrying her in a postnuptial flight, while
she remains closed and inert, into a tree.
There they will remain in coitus for an
hour, two or all night long, while he pass-
es his seed packet (the spermatophore) to
her bursa copulatrix.”
The sexually mature hibernates cele-
brate the spring equinox for three to five
weeks before the last of them departs for
their northern summer breeding
grounds by the first week in April.
The female nectars along the way
from a variety of flowers but is genetical-
ly driven to reach the first emerging
milkweed of spring as quickly as possi-
ble. The male follows, claspers ready for
grabbing and more mating. Besides the
transfer of sperm he delivers nutrients to
her that give her the strength to support
her inexhaustible search for milkweed
hosts and to reproduce. The migrants
are already eight or nine months old,
having hatched, molted, pupated and
emerged from the chrysalid the fall
before near the Great Lakes or even
Quebec.
During the early weeks of the north-
ern migration, the female might find her
first host plant in northern Mexico, but
she is likely to have to fly to southern
Texas or coastal Louisiana before she
can begin to lay her eggs. The discovery
of an unfolding milkweed kindles her
investigation. Using all six legs she
drums the leaves to assess the suitability
of the plant. Too much moisture on a
leaf would rot the egg. She tests the tox-
icity of the plant. If she has a choice, she
flies from one plant to the next, before
finding a milkweed she will accept.
Once satisfied, she lays her first
dome-shaped egg singly on the hairy
underside of the leaf. Seconds later she
is in the air, exploring the terrain for
another perfect milkweed leaf on which
to lay her next pale yellow egg. She
continued on page 26