Monarch butterflies and milkweed, enjoy a complicated relationship.
You know the type. It’s a scenario in which the two mutual parties are co-dependent upon one another. Of course, that level of dependency is fraught with pitfalls.
The majestic monarch butterfly (Danaus plexippus), is strikingly royal in appearance, and yet these delicate creatures migrate 6,000 miles roundtrip, from Mexico to Canada and back, every year.
The majestic monarch is dependent on one plant to repopulate:
The humble milkweed plant, (Asclepias syriaca).
Which Came First… The Monarch or the Milkweed?
Researchers describe the relationship between monarch butterflies and milkweed as symbiotic. This relationship status stems from the fact that the butterflies are one of the primary pollinators of the milkweed.
And, according to research conducted recently by the University of Iowa, the monarch butterfly needs the native milkweed species not only as delicious nectar but also to host their eggs and larvae.
Once the monarch eggs hatch into caterpillars, they rely solely on milkweed for their nourishment. Therefore, the larvae will not survive without milkweed.
No milkweed, no monarch butterflies.
A weed is simply a plant whose virtues have not been discovered.
~Ralph Waldo Emerson, essayist, poet, 1803-1882
The Decline of the Monarch Butterfly
If you’ve paused to wonder why you don’t see as many monarchs pass to grace your garden as often as you used to, there’s a serious reason.
The monarch butterfly is in a rapid population decline. Some estimate a staggering drop of as much as 90% of the total population.
The US Fish and Wildlife Service explains that they estimate a count of monarch butterflies in conjunction with the Mexican government. All monarchs migrate to a small region in Mexico every year to over-winter there.
There, about sixty miles from Mexico City, Mexican officials have established a 138,000 acre monarch butterfly reserve, and scientists use technology to determine a total count. [1]https://www.fws.gov/midwest/monarch/OverwinteringMonarchs.html
The reserve stretches across 12 mountains in Central Mexico. With all the monarch in this small area, Mexican scientists describe the trees as orange because they are brimming with butterflies.
“Butterflies…flowers that fly and all but sing.”
~Robert Frost, American poet
Are Monarchs Endangered?
Still, in spite of this fantastic monarch reserve in Mexico, the situation is grim.
In 2014, the US Fish and Wildlife Service was petitioned to enact Endangered Species status for the butterflies. Their researchers have spent the past five years studying these creatures.
When the decision time rolled around in 2020, the Monarchs were not yet placed on the endangered species list by the U.S. Fish and Wildlife Service. However, it’s not because they’re not endangered. They’re still below the safe threshold, however, there is a long list of species ahead of them for now.
The petition to place Monarchs on the endangered species protection act will be evaluated annually until 2024.
In Canada monarchs are slated for listing as endangered under the Species At Risk Act. In Mexico they are considered a species of special concern.[2]https://biologicaldiversity.org/w/news/press-releases/eastern-monarch-butterfly-population-up-slightly-still-below-extinction-threshold-2022-05-24/
The monarch butterfly is native to North America — spending summers in the US and Canada and wintering in Mexico They don’t exist anyplace else. The world is a brighter and more enchanted place with Monarchs around. Let’s hope they will survive and once again thrive.
What can we do? We’ll get into that in a few. First…
What’s Causing the Monarch Butterfly Decline?
So, you might now be wondering about the cause of the monarch’s sharp population drop. Scientists have pinpointed two primary reasons.
Reason for the destruction of milkweed plants and climate change.
The Diminishing Milkweed
Remember earlier I stated that there’s a co-dependency between monarch butterflies and milkweed? Not only are the numbers of monarchs decreasing, but milkweed is also in decline.
We humans have decided that milkweed is a weed and began removing it from our gardens, spraying it with chemicals, and destroying the monarch’s most essential resource. [3]https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1752-4598.2012.00196.x
Add to that the commercialization of America. As urban areas have sprawled miles out from city centers, areas that were once fields filled with milkweed are now parking lots, malls and subdivisions.
Milkweed is often destroyed in favor of lawns and ornamental plants, because… well, because it’s a weed after all.
But where does that leave the monarch butterfly? Maybe it’s time to reconsider the many benefits of weeds.
SEE: Weeds with purple flowers.
Climate Change
The reason that the monarchs winter in Mexico each year is the warm climate. Monarchs cannot survive cold temperatures.
In the past twenty years, a previously unheard-of phenomenon occurred in Central Mexico… snow! This was documented on three separate occasions: in 2002, 2012, and 2017.
😢😔😢In the 2017 blizzard, an estimated 6.2 million butterflies perished. 😢😔😢
Monarch Decline Statistics
We’ve done deep research on the exact percentage of monarch decline. However, there are so very many variables across all of the studies and numbers of decline are quite varied, from 14.8% between 2017-2018 to between 80 and 97% over the past 20 years.
Tracking on monarch population is very complicated and hard to pinpoint exactly. So in general, we recommend you not assume any statistic you hear is exactly right. To get an idea of the complexity is to begin reading the studies, and to observe how comparisons aren’t all comparing the same periods or specifics.[4]https://www.sciencedaily.com/releases/2018/11/181108091259.htm
While the monarch decline stats vary wildly, they all agree on one thing: the monarch butterfly is in severe decline.
