September in Eastern North Carolina is the beginning
of one of Mother Nature’s great annual events -- the fall migration of
the monarch butterflies. All over the United States these lovely
insects are on the move, with the eastern population heading to groves
of fir trees in Mexico where they will congregate by the millions. They
may travel up to 40 miles in a day.
recent years, however, monarch populations have plummeted nationwide,
and it is believed that their numbers have dropped from near a billion
to less than 33 million. Orley “Chip” Taylor, a professor at the
University of Kansas and the director of Monarch Watch, a monarch
conservation organization, says that we may be on the brink of an
immense ecological disaster.
says, are a keystone species, symbolic of other wildlife that are
endangered by the loss of habitat in this country. Seventy percent of
all vegetation requires pollination, and there will be a biological
cascade of effects if these species are destroyed. Butterflies and
other pollinators are necessary to maintain the infrastructure of all
wildlife, he said.
As a result of the
monarch’s decline, leaders of the United States, Canada and Mexico
discussed the wellbeing of monarchs at a one-day summit in February,
agreeing to form a working group for the conservation of the species.
They declared the monarch an “emblematic species which unites our three
Danaus plexippus, as the monarch
is known to entomologists, belongs to the subfamily, Daninae, the
milkweed butterflies. In their larval stage they feed entirely on
various species of milkweed, wildflowers with a bitter, poisonous
juice. Adult monarch butterflies continue to eat and store the noxious
glycosides found in milkweed, making them distasteful to would-be
Monarch butterfly migrations have
fascinated people for centuries. However, where the butterflies went in
the winter was a mystery until the 1970s, when 60 million to a billion
butterflies were discovered resting among the oyamel fir trees in
central Mexico near Cerro Pelon. Much about their life history is still
a mystery, and tagging projects across the country are trying to learn
It is believed that it takes four
generations to complete an annual migration. Adult butterflies leave
Mexico in the spring, and after mating, the females seek out milkweed
plants to lay their eggs on. The first three generations travel north,
each laying eggs on milkweed plants before dying at about six weeks
old. The eggs hatch into smooth, ringed, black, green and yellow
caterpillars, which feed on the milkweed and then spin bright green
chrysalises, which pupate into butterflies, continuing the migration.
The fourth generation forms a chrysalis later in the summer and may
live up to eight months, completing the trip back to its wintering
Aug. 26, three organizations -- the Center for Biological Diversity,
the Center for Food Safety, and the Xerces Society -- along with
monarch researcher Lincoln Brower, petitioned the U.S. Fish and
Wildlife Service to list the monarch butterfly as “threatened” on the
federal Endangered Species List. This listing would make it illegal to
purposefully kill a monarch butterfly or modify its habitat without a
Part of the problem lies to the south, at
the wintering grounds in Mexico. Matt Collington, the environmental
education manager at Airlie Gardens in New Hanover County, says that
while 70 acres at the wintering site are protected as a world heritage
site, the butterflies are affected by the “edging effect.” Logging all
around the site by farmers, cutting down rainforests, removes the
buffer zone that protects it, leading to colder, harsher winters that
the butterflies cannot survive.
distinguished professor of zoology emeritus at the University of
Florida and a research professor of biology at Sweet Briar College, has
been studying butterflies since 1954. He has another theory. His
research leads him to believe that the main cause of the decline lies
to the north, where agricultural practices have practically wiped out
the milkweed upon which monarchs rely.
areas where milkweed grows have been plowed and planted with crops,
mainly corn and soybeans. Most have been genetically altered to
survive spraying with herbicides such as Roundup, while the milkweed is
killed by such spraying.
blames the chemical glyphosate, contained in the pesticide Roundup, as
one of the main culprits. He explains that the production of biofuels
in this country has led to a huge increase in the price of corn,
resulting in the plowing of natural lands and wildflowers. From 2008 to
2012, he says, 24,000 acres of wildlife habitat -- an area the size of
Indiana -- was plowed and converted to corn fields. As a result,
President Obama distributed a memorandum on June 20, reasserting the
necessity of conserving pollinators, including monarch butterflies.
Mitchell, who is in charge of the Monarch Project at the N.C. Aquarium
in Manteo, adds that she thinks that the reason for monarch decline
includes agricultural use of herbicides and homeowner use of
pesticides, especially neonidcotoids -- synthetic compounds derived
from nicotine -- and residential mosquito control programs, which have
caused hive failures of bees as well.
butterflies that migrate through eastern North Carolina usually arrive
in May or June. Martha Flanagan, the coordinator of the Living
Conservatory at the N.C. Museum of Natural Sciences in Raleigh, says
that a small stable population of monarchs stays if resources are
favorable and do not continue migrating. The fall migration usually
peaks in October.
According to Taylor, many of
the monarchs that migrate along the Outer Banks get caught up in tail
winds from the ocean and die at sea. Those that make it may winter in
Florida or head farther southwest.
in North Carolina, not only corn fields but massive hog farms have
displaced wild areas where such plants as milkweed, goldenrod and other
butterfly food sources used to grow. Mitchell remembers seasons when
monarch caterpillars were so thick on the milkweed plants in the Manteo
aquarium’s wildflower gardens that they were breaking the stalks. She
says she did not see any monarchs this spring, however, and that few
have been spotted in Currituck, Edenton or southern Virginia. She
remarked that 2013 had the lowest numbers of monarchs in years, and that there have been fewer butterflies in general.
LeGrand, author of "Butterflies of North Carolina," says that,
“2014 is by far the poorest year for butterflies (including monarchs)
that I have witnessed since I began butterflying in 1991.” He
attributes this to unusual weather patterns and extremely cold winter
temperatures but acknowledges that only time will tell. LeGrand thinks
that the main cause of nationwide monarch losses is the logging of firs
in Mexico and that practices leading to milkweed loss are, in
comparison, “tiny drops in the bucket.”
the positive side, says Collington, there is great interest among
homeowners who are anxious to help out butterflies by planting milkweed
and other native species in their yards. “Conservation and restoration
of milkweed needs to be a top priority,” says Taylor.
Natural Resource Defense Council is asking state and county highway
departments to plant milkweed and refrain from mowing and using
herbicides. At the North American Leaders’ Summit in February, one of
the commitments was to create a “milkweed corridor” from Canada to
What can individuals do to help?
can refrain from using chemical herbicides in their yards and gardens,
allow native plants such as milkweed and goldenrod to grow, plant the
host and nectar plants needed by monarchs in yards, schools, parks and
roadsides, and encourage others to do the same.
to Melanie Doyle, conservative horticulturist at the Fort Fisher
Aquarium, there are 20 species of milkweed native to North Carolina.
Monarchs migrate through the Outer Banks from September through
November; and according to Doyle, they do lay eggs on the milkweed
plants and these eggs do hatch. They also feed on the nectar of seaside
goldenrod, narrowleaf or swamp milkweed, sunflowers, wild asters,
black-eyed Susans, coneflowers and a host of other flowers.
N.C. Aquarium’s monarch conservation plant sale offers three species of
native milkweed, and the N.C. Coastal Federation’s native plant sale
sells several nectar plants. Milkweed seeds can be obtained online from
the organization Monarch Watch, as well as at other sites.
Brower emphasizes that it is not too late to save the monarchs but that action must be taken now “while there is still time!”
story is provided courtesy of Coastal Review Online, the coastal news
and features service of the N.C. Coastal Federation. You can read other
stories about the North Carolina coast at www.nccoast.org.)
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