One may have supposed that the humble Monarch butterfly would not register high in importance on the agendas of the “Tres Amigos” meeting in Toluca this weekend, but Mexican President Enrique Peña Nieto managed to find time to recognize the plight of this trilateral “treasure” and vowed to step up efforts to safeguard their existence.
The butterflies’ extraordinary winter migration from Canada and the northern United States to their winter breeding grounds in the forests of Michoacan is one of the natural wonders of the world. But their numbers have dropped dramatically this year – by as much as 40 percent, according to some estimates.
Two decades ago around one billion of these distinctive orange-and-black creatures used to occupy around 45 acres of forest land in Michoacan. That figure has reduced to 35 million occupying now a meager 1.65 acres. Tourists heading to witness this phenomenon have turned up to some sanctuaries to find them virtually empty.
The reasons for the decline were pointed out in a letter sent to the presidents of Mexico, the United States and Canada by 100 Mexican and international writers and intellectuals, known as the Grupo de los 100, headed by poet Homero Aridjis. As well as climate change, the major danger facing the monarchs is a lack of milkweed to be found along their journey.Experts say that in recent years U.S. farmers have substantially increased the planting of genetically altered soybeans and corn that are able to tolerate herbicides. These toxins, however, have proven deadly to milkweed.
Monarch eggs are laid by females onto the leaves of milkweed plants, the leaves of which are the larvaes’ only source of food. So the shortage of milkweed along the 3,000-mile journey means that millions of monarchs struggle to lay their eggs, since this annual fall to spring migration occurs over the lifespans of three to four generations of the butterfly.
Feeding on milkweed, which contains certain toxins, also makes the monarchs less susceptible to predators.
To help the butterfly achieve their annual mission, the Grupo de 100 want the three nations to set up an”ecological corridor” abundant with milkweed to nourish the butterflies during their migration. Independent environmental groups are already urging farmers and householders with gardens situated long the “monarch route” to plant milkweed.