“It’s Complicated”: An Update on the Monarch Butterfly

Two months ago I posted a story here on the fate of the Monarch butterfly which many of you read and shared. This week we have an update from the New York Times that is worth reviewing briefly. There is good news and bad news, and, for me, a new sense of how complicated these things are. Many of us who are trying to help may not have been helping as much as we thought.

So listen up – this is important for the butterflies, and for us.

Let’s take the good news first: After hitting an all-time low in Mexico last year (a 90% decline from earlier population counts) numbers have rebounded a bit this year. [Personal note: It’s strictly anecdotal, but I can also report an increase. In the summer of 2013, I saw 2 monarchs all summer in Wisconsin. This summer I think the number was up to 5. For what that’s worth…]

It’s too soon, however, to take a victory lap:

“But we’re definitely not out of the woods,” said Ms. Satterfield, who studies human effects on migratory behavior. “One good year doesn’t mean we’ve recovered the migration.”

Photo: NY Times (click for source file)

The major problem for the monarch, as we pointed out in the earlier post, is loss of habitat and in particular loss of wild milkweed in my part of the world, the upper Midwestern states of the US. Because of poor agricultural practices, including expansion of corn and soybean fields and dramatic increases in the amount of the herbicide Roundup that is being used, as much as 60% of native Midwestern milkweeds disappeared between 1999 and 2009. Over that same period of time, butterfly populations plummeted 80% both in the Midwest and in Mexico.

It seems like there is an easy solution: Plant more milkweed to help replace that which has been lost in the vast agricultural lands in the region.

It appears that millions of us have done just that. I’ve done so myself – sort of. Being a kind of lackadaisical homeowner and gardener anyway, I’ve just allowed a wild patch of milkweed to proliferate. Which apparently is what most of us should have done rather than what many of us have actually been doing.

We’ve been planting the wrong kind!

(I told you this would get complicated…)

In recent years amateur conservationists have sought to replenish drastic declines in milkweed, the only plant female monarchs lay eggs on. But the most widely available milkweed for planting, the scientists say, is an exotic species called tropical milkweed — not the native species with which the butterflies evolved. That may lead to unseasonal breeding, putting monarchs at higher risk of disease and reproductive failure…

With the loss of native milkweeds that die in the fall, monarchs are encountering tropical milkweeds that are still thriving.

“There’s this huge groundswell of people planting tropical milkweed, and we don’t know what it’s doing to the butterflies,” said Francis X. Villablanca, a biology professor at California Polytechnic University. “We’re all in a rush to figure it out.”

Dr. Altizer (a disease ecologist at University of Georgia) fears that when monarchs encounter lush foliage in the fall, they may become confused, start breeding and stop migrating.

“It’s sad, because people think planting milkweed will help,” she said. “But when milkweed is available during the winter, it changes the butterfly’s behavior.”

Adding to the complexity is the fact that not all monarch scientists agree on whether this is much of an issue, and if it is, how serious it might be. Untimely breeding and infestation with parasites that are associated with the tropical variety of milkweed are two possibilities.

No one disputes that loss of milkweed habitat remains the monarchs’ biggest threat. But if the population gets smaller, risks once considered less important — like severe weather and disease — could prove catastrophic.

“We’ve learned the hard way with migratory bison and whooping cranes that once we lose a migration, it is close to impossible to bring back,” Ms. Satterfield said. “Protecting the great North American journey of the monarch is crucial now, while we still have a chance.”

So where does that leave us ordinary folks who just want to see the beautiful monarch return?

First, let’s make it a life-lesson:

Everything God has designed comes with multiple layers of complexity. Let’s try to avoid changing and damaging things and systems that God put in place and that have been functioning beautifully for thousands of years. Let’s apply the precautionary principle with new vigor.

And second, if we are among those who have tried to help and might have the “wrong” kind of milkweed in our yards, all is not lost:

Butterfly enthusiasts shouldn’t feel bad for planting tropical milkweed, monarch researchers say. But they should cut the plants back in fall and winter. Or even better, replace them with natives. There are native plant societies across the country that can offer advice.

In fact, you can come by my yard if you like. My natives are definitely acting like weeds, and my wife would love it if you’d take some off my hands!

Photo by Janet Wachter, who usually just takes pictures of flowers. See her work every day on the Care of Creation Facebook page.