Milkweed, monarchs and Mexico
For a long time I thought of milkweed as a weird plant. I didn’t know what to make of its spongy pod that oozed a white sticky liquid if you squeezed when it was still green. Then, in the fall, the pods burst open, sending thread-fine feather seedlings off to propagate themselves in the fields I’d go walking in near my mom’s home in Ohio. By late November the pods became transformed into dry empty shells, dulled grey by the wind and sun. Milkweed stalks listed into the coming winter winds like drunks weaving this way and that as they stumbled down a city sidewalk.
My good friend Richard Dubé opened my eyes to its rightful place in the world. It was the summer of ’82. I’d just graduated from the University of Southern Maine with a degree in English literature. I fell back to my old ways and became, once again, a day laborer. I’d been pulling weeds in the back nursery at Lucas Tree Experts, where Richard worked as a landscape designer, and he’d come outside to see how I was doing. He pointed to a small cluster of milkweed plants, pods unopened, still green and standing tall.
“Do you know what I think of when I see milkweed?” he asked me.
Here, I should mention that Richard is a trained naturalist. He earned his degree in forestry at Hocking Technical College in southeastern Ohio. That’s where he met Mary, fell in love and got married. I missed their wedding, but they didn’t hold that against me. A few years later they moved to Maine, allowing my friendship with Richard to deepen with weekend hikes in the mountains of New Hampshire and western Maine, beach excursions on Cape Elizabeth, and regular bird-watching and botany walks at Gilsland Farm in Falmouth. Sometimes Mary would join us, but more often it would be just Richard and me ambling along with cameras or binoculars around our necks, ever alert to the possibility of the world revealing itself as wondrous strange. For me, those walks invariably were enriched by Richard’s impromptu lessons in botany.
“I don’t know,” I replied. “The pod looks like an Irish currach, the bunched seedlings like the scales of a fish. What about you?”
“Mexico,” he said.
“Mexico? How so?”
“The monarch butterfly, Danaus plexippus, is the only butterfly that migrates both north and south. For a long time no one knew where they spent the winter months. Now we know. They winter in the mountains of central Mexico. They fly there by the millions, clustering in colonies on pine and oyamel fir trees. They’re so thick the trees turn orange in color and branches sag from the weight.”
“What’s that got to do with milkweed?” I asked.
“Everything,” he said. “Without milkweed, monarchs wouldn’t exist. Common milkweed, Asclepias syriaca, is the principal food source for monarch butterfly caterpillars. It’s named after Asklepios, the Greek god of medicine and healing … which is interesting, because the milky latex in the leaves is a toxin. The caterpillars accumulate these toxins and when they turn into butterflies the toxins are concentrated in their wings and exoskeletons. Birds and other predators learn that the monarch butterflies taste bad. Sometimes they even vomit. Long story short: they avoid preying on monarchs.”
“OK, so milkweeds are good for monarchs. What’s the connection to Mexico?”
“That’s where they go for the winter, by the millions …”
That conversation took place almost 30 years ago. Even now, remembering the gist of it, the tingle of the epiphany I felt comes rushing back to me. My friend’s generous lesson might well be the first conscious understanding I had of the powerful reality of coevolution and the multiple networks that connect … well, everything.
“Milkweeds, monarchs and Mexico” became for me a shorthand reminder of how our world is, truly, one vast web of inter-being.
In ancient India, this understanding is conveyed by the beautiful image of “Indra’s net,” which stretches infinitely in all directions, with a single jewel glittering at each vertex, reflecting infinitely all the other jewels that are similarly strung like a galaxy of glittering stars. As above so below: delve into any small patch of earth, pick a plant or an insect or bird, and then follow the jewel-adorned threads of net outward and see where they might take you. Monarch butterflies ride the wind, making their way south to their wintering grounds in a volcanic mountain region of central Mexico; Indra, the god of rain and thunderstorms, is the “one who rides the clouds” or sometimes a white elephant. Which image requires more imagination to believe as true?
A good many years later my simplistic notion of the monarch’s migration from the milkweed fields of Maine to a small mountainside forest in Mexico took an unexpected leap into a deeper realm of mystery.
I’d been reading an article, probably in a National Geographic magazine, reporting that monarchs flying north from Mexico die long before it’s time to head back the next winter.
What that means is that the monarchs’ migration, both north and south, is completed by a different generation than the one beginning the journey -- four generations later, according to researchers.
Four generations, four different butterflies, each going through the four stages of the monarch’s life cycle: Egg, then larvae (caterpillar), pupa (chrysalis) and adult butterfly. Four stages during one life cycle, and that life cycle goes through four generations in one year during the monarchs’ migration from, or to, Mexico. Truly, Indra’s net! Each generation of butterfly enjoys a life of about two to six weeks … except for the fourth generation. These butterflies, born in late summer or early fall, will live for up to eight months, time enough to make the long journey to Mexico, where they will hibernate, mate and die just as a new generation emerges to journey northward and start the cycle all over again.
Somehow, the map to the wintering grounds gets passed on to the generation that needs to find its way to where it all begins, or ends, take your pick. The monarchs’ migration is guided by an inborn genetic GPS system over thousands of miles, with fields of milkweed plants along the journey ripening just in time to provide essential food and cover for eggs and larvae as well as flowers for the emerging butterflies to pollinate.
Not quite a month ago, on March 14, a headline migrated into my computer courtesy of Common Dreams.org: “Herbicides for GMOs Driving Monarch Butterfly Populations to ‘Ominous’ Brink.” I felt like I’d just been told a dear friend was ailing, in the hospital, prognosis uncertain.
Too quickly I jumped to the conclusion that it had something to do with continued logging of the monarch colonies’ winter grounds in the Monarch Butterfly Special Biosphere Reserve. Created in 1986 to protect the forests they depended up, I knew that logging of the pine and oyamel fir trees has continued.
But the Common Dreams article cites a newer threat: The use of genetically modified crops in the American Midwest, accompanied by the intensive use of the milkweed-killing herbicide glysophate on 120 million acres of crops, according to staff writer Lauren McCauley.
A critical feeding ground — the milkweed plants growing up between millions of acres of soybean and corn — is being killed off because Monsanto has genetically modified the seeds of those crops to enable the mature crops to withstand extremely heavy doses of its glysophate herbicide, called Roundup. The corn and soybean genetically modified seed is called Roundup Ready; milkweed and other wild plants that flower and provide nectar to bees as well as butterflies have no such protection.
“Before Roundup-Ready crops, weed control was accomplished by running a tiller through those fields and chopping up the weeds and turning over the soil, but not affecting the crops,” Chip Taylor, a University of Kansas insect ecologist told Yale Environment 360. “The milkweed survives that sort of tillage to some extent. So there were maybe 20, 30, 40 plants per acre out there, enough so that you could see them … They have effectively eliminated milkweed from almost all of the habitat that monarchs used to use.”
The monarch colonies in Mexico that used to average 22 acres hit a record low of 2.9 acres this winter. Taylor estimates the monarchs’ population declined by 59% from the previous year. Along with bees, monarchs are one of the principal pollinating insects in North America. Bees are dying in record numbers as well.
Monsanto, meanwhile, is the beneficiary of a rider attached to a spending bill aimed at averting a government shutdown. Congress approved HR 933 and President Obama signed it into law on March 26. The rider, which seems fairly described as “The Monsanto Protection Act,” effectively bars federal courts from being able to halt the sale or planting of controversial genetically modified or genetically engineered seeds, no matter what health issues may arise concerning GMOs in the future. Many members of Congress say they were unaware of the rider when they approved the bill. A grassroots campaign is under way to strike down that 11th-hour rider.
Monarch butterflies are heading North in one of the world’s greatest migrations. How many will not find the food they need to complete the journey?
Indra’s net is being torn asunder.
how long … how long!
milkweeds, monarchs, Mexico