Fall of the Monarchs

Can we save North America’s most beloved butterfly?

Molly M. Ginty December 5, 2012

As a girl grow­ing up on the out­skirts of Cedar Rapids, Iowa, Deb­bie Jack­son looked for­ward every May to hop­ping on her bike, ped­al­ing to near­by fields and col­lect­ing the just-laid eggs of monarch but­ter­flies from milk­weed plants. I saw count­less orange-and black mon­archs flit­ting through the wild­flow­ers then, and could find their eggs, take them home, and hatch them eas­i­ly,” says Jack­son. But that was 40 years ago, before the mon­archs start­ed to die.”

A University of Minnesota study linked the monarch decline to glyphosate, aka Roundup. In the United States, 94,000 tons of the herbicide are applied each year.

Today, liv­ing on 10 acres out­side Davis­burg, Mich., Jack­son grows four types of milk­weed in a but­ter­fly gar­den” and fills her house with plas­tic con­tain­ers in which she hatch­es but­ter­fly eggs. Jack­son spends more time on but­ter­flies than on her part-time finance job because she is alarmed by the mon­archs’ pop­u­la­tion decline. Sci­en­tists say that the down­fall has been caused in small part by envi­ron­men­tal fac­tors, but most­ly by two types of human med­dling: the use of her­bi­cides that are killing off milk­weed plants in the Unit­ed States, and the ille­gal log­ging of the pine and fir trees on which the mon­archs make their homes for five months of the win­ter in cen­tral Mexico.

Jack­son, a vol­un­teer for Monarch Watch, is part of a grass­roots coali­tion of ento­mol­o­gists, con­ser­va­tion­ists and activists on both sides of the bor­der. Their efforts to save the mon­archs include a num­ber of strate­gies to slow or halt U.S. her­bi­cide use and Mex­i­can logging.

Monarch but­ter­flies warn of what might lie ahead for oth­er wild crea­tures affect­ed by over­farm­ing and defor­esta­tion,” says Chip Tay­lor, pro­fes­sor of insect ecol­o­gy at the Uni­ver­si­ty of Kansas in Lawrence, who found­ed Monarch Watch in 1992.

It’s clear that this year’s total pop­u­la­tion is down, and that the over­win­ter­ing group that just arrived in Mex­i­co is among the low­est ever recorded.”

The dev­as­tat­ing reduc­tion start­ed 15 years ago — very recent­ly in the monarch’s long his­to­ry. An esti­mat­ed 250,000 years old, this species pre­dates mod­ern humans by 50,000 years and has until now enjoyed a har­di­ness that belies its 4‑inch wingspan and 0.2‑ounce weight.

Monarch but­ter­flies feed on the nec­tar of a vari­ety of flow­ers, such as the cone­flow­ers and daisies that Jack­son grows in her gar­den. They lay their eggs on a once-ubiq­ui­tous plant: the light green, fuzzy-leafed milk­weed, named for its rub­bery, milk-col­ored sap. Because mon­archs mul­ti­ply in such vast num­bers, they have until now been able to win­ter safe­ly in just one 60-square mile area, clus­ter­ing on south-fac­ing slopes that are 10,000 feet above sea lev­el in the moun­tains of Mexico’s Michoacán state.

Every March, mon­archs wake from their win­ter slum­ber, warm their wings in the spring sun­light, and begin the fren­zied busi­ness of mat­ing. As swarms of them start fly­ing north­ward, the females lay their eggs on milk­weed plants that the hatch­ling cater­pil­lars will eat. New but­ter­flies emerge from cocoons and begin to trek north, mat­ing and lay­ing eggs by the bil­lions. The mon­archs fan out across the Unit­ed States and up to Cana­da, where the fourth gen­er­a­tion, descend­ed from the hiber­nat­ing pop­u­la­tion in Mex­i­co, turns around and starts fly­ing south to Michoacán at an aver­age rate of 50 miles per day.

From June to Sep­tem­ber, in the three short months that they migrate from Cana­da to Mex­i­co, the mon­archs jour­ney 3,000 miles. They start their jour­ney fly­ing solo, then gath­er in a swarm that is 50 miles wide and casts a shad­ow as it cross­es the U.S.-Mexico border.

Researchers have yet to deter­mine what guides the mon­archs — whether it is smell, water, sun­light, mag­net­ic fields, or some hard­wired form of but­ter­fly radar. All sci­en­tists know is that the mon­archs know where to go. If you catch and crate a large group of them, fly them in planes hun­dreds of miles off course and release them, they will still head straight to Mexico.

Mex­i­cans con­sid­er the but­ter­flies to be the souls of their depart­ed ances­tors and every Octo­ber wel­come las monar­cas with bois­ter­ous fes­ti­vals. But this year few­er but­ter­flies have showed up for the par­ty. They cov­er just 7 acres of for­est ver­sus the opti­mum 15, with a grow­ing num­ber dying right after arrival. One by one, they tum­ble life­less from the tall trees. Their del­i­cate, bright wings car­pet the for­est floor.

Sub­ur­ban sprawl and recent droughts both threat­en the milk­weed that is essen­tial to the mon­archs’ sur­vival. But sci­en­tists say most of the mon­archs’ down­fall is like­ly tied to mod­ern-day agri­cul­tur­al practices.

In March, a Uni­ver­si­ty of Min­neso­ta study linked 10 years of monarch decline to glyphosate, the most pop­u­lar her­bi­cide in the Unit­ed States, used in brands such as Monsanto’s Roundup. An esti­mat­ed 84,000 tons of glyphosate are applied annu­al­ly to soy­beans, corn and oth­er U.S. com­mer­cial crops. On top of this comes 3,600 tons used in the home and gar­den sec­tors, and 6,800 tons used by pri­vate busi­ness­es and gov­ern­ment agencies.

Though glyphosate may be a boon to farm­ers and land­scap­ers, it is killing milk­weed — nor­mal­ly among the hardi­est and most stub­born of plants — in record num­bers. One recent study found that the milk­weed pop­u­la­tion in the Mid­west plunged 58 per­cent from 1999 to 2010, and that as a result, monarch egg pro­duc­tion plum­met­ed 81 percent.

The but­ter­flies’ win­ter rest­ing grounds are also under threat. Michoacáns near the state’s 12 but­ter­fly reserves often turn to ille­gal log­ging because they have few oth­er sources of income. It can take an ille­gal log­ger less than an hour to chop down a pine tree that has been shel­ter­ing mon­archs for cen­turies. From 1986 to 2006, 20 per­cent of the for­est reserves in Michoacán were dis­turbed,” says Maria Isabel Ramirez, a geo­g­ra­ph­er and con­ser­va­tion­ist from the Nation­al Autonomous Uni­ver­si­ty of Mex­i­co. More than 60 per­cent of this loss is tied to ille­gal extractions.”

To counter this, the World Wildlife Fund, a Wash­ing­ton, D.C.-based non­prof­it, pays Michoacán vil­lagers to patrol for­est reserves and pro­tect them from ille­gal log­ging. Sim­i­lar­ly, Eco­l­ife, which is based in Escon­di­do, Calif., pro­vides vil­lagers with new­fan­gled stoves that require less pine and fir wood than tra­di­tion­al ovens do. And the Roseville, Minn.-based Monarch But­ter­fly Fund plants 30,000 seedlings per year in this threat­ened for­est region.

In the Unit­ed States, but­ter­fly lovers are off­set­ting the milk­weed die-off by build­ing monarch way sta­tions,” such as the milk­weed gar­dens that are now grow­ing every­where from a con­ven­tion cen­ter roof in Pitts­burgh to Deb­bie Jackson’s back­yard in Davis­burg, Mich.

Now that Jackson’s but­ter­fly gar­den­ing sea­son has end­ed, she is busy giv­ing but­ter­fly talks at local schools, and mak­ing the rounds at com­mu­ni­ty groups and church­es, inspir­ing oth­ers to adopt some of the 1,500 monarch eggs that she will give away next sum­mer. Indoor hatch­ing boosts the cater­pil­lars’ sur­vival rate, a grim 2‑to‑5 per­cent in the wild, to a robust 90 percent.

I want every­one to wit­ness the mir­a­cle that I did as a child,” says Jack­son. When you watch a new­ly hatched monarch hang from your fin­ger and unfurl its wings, you can’t help but ded­i­cate your­self to this creature’s survival.”

Mol­ly M. Gin­ty is a jour­nal­ist who writes for Ms., Wom­en’s eNews, On the Issues, the Utne Read­er, The Nation and oth­er pro­gres­sive publications.
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