Wings without borders: the case for a Migratory Insect Treaty to aid monarch butterflies.

Author:Yust, Meena Miriam

For hundreds of years, migratory birds have been protected through treaties, yet that same protection has not been afforded to migratory butterflies. Monarch butterflies in particular are known for migrating over 3,000 miles through multiple generations from Mexico to the U.S. and Canada. Their population has been declining significantly over the last several decades. Butterflies, like other insects, are often overlooked; yet insects provide the U.S. $57 billion worth of ecological services. (1) This Note argues that the U.S., Mexico, and Canada should enact a Migratory Insect Treaty to aid monarch butterflies and other migratory insects in order to protect their populations. In addition, this Note provides a draft treaty with commentary as a starting point for consideration of such an instrument.

CONTENTS I. INTRODUCTION II. THE UNUSUAL CIRCUMSTANCE OF THE MONARCH BUTTERFLY A. The Population Decline 1. Forest degradation in Mexico and climate change 2. Breeding Habitat: The effects of lack of milkweed hosts and genetically modified corn B. A Comparison of Monarch Butterfly Laws: Mexico, Canada, and the U.S II. RELEVANT INTERNATIONAL TREATIES AND THEIR COMPLICATIONS A. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (1973) B. Migratory Bird Treaties C. "Soft Law" Monarch Conservation: The North American Monarch Conservation Plan D. Convention on Migratory Species E. The Problem with Laws Emphasizing Trade and Hunting IV. DRAFT TEXT OF MIGRATORY INSECT TREATY WITH COMMENTARY. V. CONCLUSION I. INTRODUCTION

A recent study has valued the ecological services insects provide within the U.S. at $57 billion, (2) and this figure is gauged by many to be an underestimate. (3) Yet humans have increased the rate of extinction of insects exponentially. (4) In the U.S., insects are an underrepresented class of animal in the Endangered Species Act due to the way the act is constructed. (5,6) Additionally, current treaties banning trade of endangered species are seldom relevant to insects because they are rarely hunted. Sometimes extinctions go unnoticed, as there are not enough biologists to identify lost insect species. Indeed, five to eight million insect species remain undiscovered. 6 We are well aware that if honeybees faced extinction, our food supply would be in a dire state. But many insects besides bees pollinate and contribute to modern society and our way of life. (7)

The monarch butterfly (Danaus plexippus) in particular still remains a wonder of science and a beauty of nature, in addition to being a pollinator. These butterflies migrate over 2,000 miles from Mexico to Canada over multiple generations, and researchers still do not know how the monarchs navigate their journey. (8) Birds and mammals learn migratory routes from their parents, but butterflies do not live long enough to teach their offspring how to migrate. (9)

The monarch butterfly population has steadily declined since 1994. (10) This is due primarily to three factors: (1) illegal logging in the Oyamel forests of Mexico, where the butterflies spend the winter; (2) a lack of milkweed plant hosts in the U.S. and Canada, possibly coupled with genetically modified crop effects; and (3) climate change. (11) Mexico, Canada, and the U.S. have signed protective migratory bird treaties, and a similar treaty is necessary for migratory insects to prevent the decline of the monarch butterfly and species like it.

This Note explores the current threats to monarch butterflies and how to remedy them through international law. Section II provides background on the monarch butterfly migration and threats to its population. Section III discusses current laws and treaties for other migrating species. Section IV then proposes a draft migratory insect treaty to aid monarch butterflies and insects like them.


    Every year, about 60 to 120 million monarch butterflies migrate from the forests of central Mexico to the U.S. and Canada. (12) Remarkably, through multiple generations, (13) monarchs migrate over 3,000 miles, and offspring along the way instinctively know their course. (14) How the new generation finds its bearings with such remarkable accuracy is still a mystery of science. (15)

    The North American monarch population is split into Eastern and Western populations. (16) The Eastern population is found east of the Rocky Mountains and spends the winter in Mexico, while the Western population spends the winter in California. (17) The Eastern population breeds from the southern U.S. to southern Canada as well as from the Atlantic coast to the Rocky Mountains. The Western population ranges from the Rocky Mountains to the Pacific coast and from the Canadian border to the southern U.S. (18)

    One reason that monarchs require special protection is their dependence on particular plants. (19) Monarchs must lay their eggs on milkweed plants, which are essential to larvae survival. (20) Monarchs complete "almost all of their growth during the larval stage," (21) and remarkably, about 90 percent of eggs die during the egg and larval stages. (22) With such a low survival rate, it is critical that plant and environmental conditions are adequate.

    Monarchs are susceptible to harm when environmental needs are not met. Eggs do not hatch in dry conditions, and young larvae may perish at high temperatures. For instance, 95[degrees] Fahrenheit is lethal to each stage. Temperatures below freezing can also kill, (23) and rain compounded with cold temperatures is an especially deadly combination. According to some experiments, 5 percent of wet monarchs freeze to death at temperatures of -3.0[degrees] Celsius, 50 percent at -4.0[degrees] Celsius, and 80 percent at -5.0[degrees] Celsius. (24) This problem is exacerbated as forest degradation exposes monarchs to rain and wind, thus increasing the risk of mass freezing.

    In addition to moderate climate, monarchs require particular environmental conditions in order to complete their long migration. They must be able to: (1) overwinter in Mexico or California; (2) hatch and grow with nourishing milkweeds in the U.S. and Canada; and (3) have safe passage free of environmental hazards on the journey from Mexico to the U.S. and Canada. Unfortunately, monarch butterflies are increasingly vulnerable at every stage of this migration.

    1. The Population Decline

      Existing laws are not curbing the population decline of monarch butterflies. (25) As shown in a recent study, the monarch population has been steadily declining since 1994. (26) Three factors contribute to the problem: degradation of forests in Mexico, climate change, and loss of breeding habitat in the U.S. (27) This Note will address each in turn.

      1. Forest degradation in Mexico and climate change

        Illegal commercial logging has significantly reduced Mexican forests. A study performed by the Geography Institute of Universidad Nacional Autonoma de Mexico (UNAM) revealed that 44 percent of high-quality forests in the Monarch Butterfly Biosphere Reserve were degraded between 1984 and 1999. (28) Some biologists conclude that illegal logging is a more severe problem for monarch butterflies than is agricultural clearing. (29) Research has revealed that monarchs need forest cover as an umbrella to protect them from the cold. (30) Furthermore, clustered butterflies were found to have "significantly higher lipid mass, water content, lean mass, and larger wings than did monarchs collected from flowers," (31) demonstrating that an intact, closed forest is necessary for successful overwintering, allowing monarchs to conserve lipid reserves for the long spring migration. (32) Scientists have consistently witnessed the severe effects of forest thinning on monarchs, as insufficient cover increases the insects' risk of freezing. (33) In 2010, a single storm blew hundreds of trees down in the Monarch Butterfly Special Biosphere Reserve, and researchers estimated that over fifty percent of monarchs were killed. (34) Had the temperature drop to -6.0[degrees] Celsius occurred while the monarchs were still wet, rather than on the second morning when they had dried, there would have been a shocking over 90 percent mortality rate. (35) Thus, a combination of severe weather and degraded forests is devastating to the monarch population. (36)

        Earlier, in 1981, a colony known as the "Zapatero overwintering colony" in the Sierra Chincua region of Mexico was shattered by severe weather conditions, causing 2.7 million monarchs to die in a ten-day storm. (37) In 1992, prolonged cold and cloudy weather caused an 80 percent population reduction in the Sierra Herrada colony. (38) It was discovered that the body temperatures of monarchs had dropped to 15[degrees] Celsius below freezing. Later, in 2002, a storm with heavy rain and snow caused an estimated 500 million monarch deaths across multiple colonies in central Mexico. (39) Of two colonies tested by scientists, an estimated 75 percent of monarchs were killed due to the 2002 storm. (40) While the effects of climate change are outside the scope of this Note, forest degradation is an issue that the proposed treaty addresses, and severe weather trends increase the urgency of such measures.

        The rate of forest degradation in Mexican overwintering sites has been increasing since 1971. (41) According to the World Wide Fund for Nature and the Mexican Nature Conservation Fund (FMNC), illegal logging has caused most of the deforestation. (42) Additionally, eco-tourism to overwintering sites in Mexico can have a degrading impact on monarch habitat, as many sites are not regulated and protective measures may not be in place. (43)

        Socio-economic factors also create particular complications in Mexican forest conservation. The Mexican population has a growing demand for wood, (44) and low wages coupled with a mafia-style association linked to the timber industry pressure locals (sometimes under...

To continue reading