Imagine a state of laws where murder is illegal if the victim is clad in a blue shirt, but legal if the victim is not wearing blue. A system where robbery is illegal if the victim has white skin but legal if the victim has dark skin. Such a system would be an outrage in human society. But this is the system of laws we have created for others.
Other species, that is. For hundreds of years we have had treaties protecting migratory birds who traverse countries, but no similar protections for non-feathered fliers who also cross borders, such as butterflies. Butterflies are not protected under any treaty, and consequently their populations are in danger. Unlike birds, butterflies are a member of the class Insecta, along with bees and other pollinators.
When a German study reported last year a more than 75 percent insect decline in protected areas over 27 years, the news was particularly disturbing because insects are prodigious pollinators. Perhaps even more concerning, scientists have determined that the Sixth Mass Extinction is underway.
On the American continent, we have the sad declining numbers of the beautiful monarch butterfly (Danaus plexippus). Striking in appearance, these orange-and-black-winged beauties are also a biological phenomenon: their migration covers a journey of 3,000 miles, three countries and multiple generations, from their winter home in Mexico to as far north as Canada . . . and then another 3,000 miles on the return trip. A recent article in Science analyzes their plight and the complexity of threats against survival. A population declining for decades, it is threatened by habitat loss, pesticides, extreme weather, disease, and much variation in migratory success. Reproduction along the migratory route is particularly vulnerable as monarch caterpillars rely on milkweed for survival, and it has diminished.
In March this year counts by Mexican officials revealed a population decline for the second consecutive year. Only nine colonies were found, reduced from 13 last year. A declining population since 1994 has now made their migration an endangered biological phenomenon according to scientists.
A longitudinal study conducted over 38 years and recently published in Global Change Biology, has traced the birthplace of monarch butterflies in North America by examining chemical compositions of wing tissue samples. Focused exclusively on the generation of monarchs born in North America that continue their migration to overwinter in Mexico, it established regional climate as the greatest predictor of change in natal origin. Monarch caterpillars rely on milkweed, and the most important implication of this study is that planting milkweed hosts solely in the Midwest is not sufficient. Climate change forces the butterflies to breed in other regions.
Thus, to sustain monarch populations, abundant milkweed is needed not only in the Midwest but throughout the United States. In fact, the U.S. Geological Survey has concluded that as many as 1.8 billion additional milkweed stems are needed to return these butterflies to a sustainable population.
Unfortunately, despite these needs, international law promises little aid for the monarch. The Convention on Migratory Species (CMS), backed by the U.N. Environment Program, aims to “conserve terrestrial, aquatic and avian migratory species throughout their range.” While the monarch butterfly has been added to the list of species for conservation, neither the U.S. nor Mexico nor Canada is a party to the convention.
In 2007, the Commission for Environmental Cooperation held a conference in Morelia, Mexico, leading to the creation of the North American Monarch Conservation Plan (NAMCP), which proposes multilateral action between Mexico, Canada, and the U.S. The NAMCP is certainly a step in the right direction, outlining objectives for butterfly conservation, yet it does not have the ability to wield the power of enforcement mechanisms in a treaty, nor does it set forth specific mechanisms or measures to achieve its ends. The need for an enforceable treaty thus remains.
There is also the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), entered into force on July 1, 1973. It is designed to “ensure that international trade in specimens of wild animals and plants does not threaten their survival.” The United States, Mexico, and Canada are all parties. Monarch butterflies are not currently listed under CITES for protection. As CITES regulates trade, and monarch butterflies are generally not hunted in quantity, it is unlikely that CITES could ever help monarchs.
In 2014, a petition was filed to protect monarch butterflies under the Endangered Species Act. The U.S. Fish and Wildlife Service’s decision is due in June 2019. If granted, protection under the Endangered Species Act would help monarchs in the U.S. Yet this attacks only half the problem, as it does not cover Mexico where they return for the winter.
Monarch butterflies have essentially slipped in the cracks. There is no treaty protecting them and they desperately need cross-border protection as has been afforded migratory birds for hundreds of years through the treaties in North America and Europe.
What is crucial is the creation of a carefully drafted Migratory Insect Treaty, tailored to address the unique challenges facing insects like the monarch butterfly. Such a treaty would protect monarchs, whose cross-border travels span three countries – Mexico, Canada, and the U.S. – and who face challenges in each country from illegal logging of overwintering habitat in Mexico to lack of milkweed and flowers further north, and climate effects in all three. Across the Atlantic, it could also protect the painted lady (Vanessa cardui), a cousin of the monarch. Present on every continent except South America and the Antarctic, it is famous for one group’s migration from North Africa to as far as the Arctic and back – an amazing round-trip of 9,000 miles. A migratory treaty would include measures and enforcement mechanisms for each country, to ensure protection of a species with unique needs, and also allow other species to be added later.
Thus, in aid of monarch butterflies, the United States would be obligated to return native milkweed plants alongside highways, particularly those that previously housed native milkweed. And Mexico would have to undertake measures to curb deforestation of the overwintering habitat in Mexico. Both are necessary for the monarch’s survival.
In addition, the ecological and economic benefits due to insects are also profound. Insects provide the US with $57 billion worth of ecological services, a figure thought by many to be an underestimate. Humans have increased the rate of insect extinction exponentially, endangering the almost 80 percent of the world’s crops that require pollination. Consequently, treaty protection is also economically important. Legal cover protects habitat for the insects in their countries of migration; in turn, the insects serve as necessary pollinators.
Insects also have been found to have immunological, analgesic, antibacterial, anesthetic, and anti-rheumatic properties. Eight hundred species of terrestrial arthropods, the phylum that includes insects, show anticancer activity. Promising anticancer drugs have been isolated from the wings of Asian sulfur butterflies (Catopsilia crocale). Some insects might even have qualities as yet unknown, making it vital to ensure each species of insect survives.
Vladimir Nabokov, the author of “Lolita,” was also a lepidopterist. It was he who named the tiny Karner blue butterfly (now endangered), whose life cycle, and thus survival, depends on the blue lupine flower. He described its stunning beauty in his novel “Pnin”:
“A score of small butterflies, all of one kind, were settled on a damp patch of sand, their wings erect and closed, showing their pale undersides with dark dots and tiny orange-rimmed peacock spots along the hindwing margins; one of Pnin's shed rubbers disturbed some of them and, revealing the celestial hue of their upper surface, they fluttered around like blue snowflakes. . .''
When beauty is lost, the world is a diminished place.