Monarch
Almost every day I spend a little time down in my field waist-high in the milkweed searching for caterpillars and hoping for the sight of a Monarch. This summer I have seen ten Monarchs in all and none have been spotted in my field. Of course, Monarchs don’t need to feed on milkweed nectar; they have many other choices. And this year the milkweed flowers bloomed so early that most Monarchs weren’t even around to feast on the fragrant flowers. I usually don’t start seeing these beautiful butterflies until early July and sightings used to peak around the end of the summer here in Maine. The startling flaming orange Mexican sunflowers and Liatris are favored monarch nectar blossoms. I grow neither here because I don’t have full sun, but I do have Butterfly weed, lots of it, and twice a Monarch has visited, along with clouds of Frittilaries.
Even if flowers are barely open, or have passed quickly in the heat, Monarchs have an amazing variety of sensors, including antennae and chemoreceptors on their legs that allow them to detect the plants they are encountering for edibility. While Monarchs are able to fly long distances to find milkweed host plants and nectar sources, widely spaced milkweed patches mean that females need to search longer to find places to lay eggs, and thus they lay fewer eggs over the course of their lives.
Wading through fields in search of Monarch caterpillars is something I have been doing most of my life. In the spring I plant acorns, raise frogs and toads; in the fall I watch Monarch caterpillars transform into butterflies…or I did. I still plant acorns, raise frogs and toads but now, even if I find a caterpillar I leave it where it is. So far this year I haven’t seen one, but I keep looking…
Global statistics on the decline of all insects, which include the Monarch, vary from 40 – 75 percent, depending upon the sources consulted and regions studied. Some places have not been researched so the picture is not complete. Scientists are deeply concerned about what might be the worst threat of all –Climate Change – but even without the latter, the general trend is alarming because these butterflies, like all invertebrates, are at the bottom of a food chain that affects us all, human and non-humans alike.
According to the National Academy of Sciences (PNAS), not all insects are declining. Some moth species are increasing. Numerous temperate insects, presumably limited by winter temperatures, have also increased in abundance and range, in response to warmer global temperatures. Around here the prevalence of ticks, especially deer ticks, are excellent examples. Mayfly swarms are also on the increase. In some places, native herbivores have flourished by utilizing nonnative plants as adult nectar sources or as larval food plants, and there are even instances where introduced plants have rescued imperiled species.
However, “Monarchs are the face of the wildlife extinction crisis,” states a senior scientist at the Center for Biological Diversity.
The eastern Monarch population is made up of the butterflies east of the Rocky Mountains and accounts for roughly 99% of all North American Monarchs. The butterflies migrate each winter to Oyamel fir forests on high-elevation mountaintops in central Mexico to spend the winter. Scientists estimate the population size by measuring the area of trees turned orange by the clustering butterflies. That population has been dangerously low since 2008.
In December of 2020, the U.S. Fish and Wildlife Service put monarchs on the waiting list for Endangered Species Act listing, which confers no actual protection for them or their habitat. Yet the U.S. Wildlife organization has estimated up to an 80% probability of population collapse for eastern Monarchs within 50 years and a 96-100% probability for the western population (This organization cannot be trusted – this kind of ‘double speak’ is normalized).
“Now the 2021 count shows Monarch numbers declining even further,” states the Center for Biological Diversity because of Monsanto’s toxic Roundup. Monarchs are threatened by pesticides, herbicides, global climate change, loss of habitat, and illegal logging of the forests where they migrate for the winter. They are also threatened by mortality during their migrations from roadkill.
Monarchs have lost an estimated 165 million acres of breeding habitat in the United States to herbicide spraying and development in recent decades. The caterpillars only eat milkweed, but the plant has been devastated by increased herbicide spraying in conjunction with corn and soybean crops that have been genetically engineered to tolerate direct spraying. The butterflies are also threatened by neonicotinoid insecticides, fungicides, and other chemicals that are toxic to young caterpillars.
Monarch butterflies west of the Rocky Mountains overwinter on the central coast of California. Their numbers have plummeted by 99%, and fewer than 2,000 total butterflies were counted this winter (2020 -21). The western migration has collapsed in part due to warmer winters, pesticides, loss of habitat, etc., and to people planting invasive tropical milkweed.
An eastern Monarch’s relationship with the climate is complicated. This insect is not a typical migrant that spends the winter in the south, comes north to breed, then returns south in the fall. Monarchs take a number of generations each year to reach their northern breeding areas and if even one of these areas is compromised it can affect the whole cycle. The fourth (or less common) fifth generation born during the late summer is the one that makes the long journey south to Mexico from Maine each fall.
The yearly count of Monarch butterflies overwintering in Mexico (2021) continues to show a dramatic decline in this imperiled species. Today’s count of 2.10 hectares (5.2 acres) of occupied winter habitat is down 26% from last year’s count.
The minimum population threshold needed to be out of the danger zone of extinction is six hectares. In the wintering sites in Mexico, as forests become more heavily degraded by logging and drought trees are less able to buffer the Monarchs from temperature extremes, including both warm daytime temperatures and cold nighttime temperatures.
What can we do to help the Monarch butterfly stay with us as long as it can?
Some solutions are simple. Plant milkweed, or simply let it go wild instead of mowing down entire fields where it grows naturally. I mow my small field in the fall once after all the birds have fledged and most of the autumn flowers are spent (wild asters and goldenrod continue to bloom around the edges of my field attracting late Monarch arrivals). This approach allows me to keep a protected open space during three seasons and still allows for summer’s wild abundance.
If you don’t want a flower garden, create a wildflower meadow like my neighbor has. Peter’s Meadow is replete with red and white clover, daisies, vetch, black eyed susans, blue grass, yarrow, milkweed, and more. I have seen two Monarchs feeding in this lovely space.
If you garden, plant flowers the Monarchs are attracted to, like Mexican Sunflower Liatris, Salvia, Butterfly weed, Bee balm, Vervain, Verbena, Zinnias – there are so many excellent choices – visit our local pollinator garden to see what Mahoosuc Land Trust (MLT) has planted to attract the Monarch butterflies.
Stop using pesticides/herbicides ANYWHERE.
Stop growing genetically engineered seeds.
Boycott Monsanto.
Join an organization that is dedicated to working with the overwhelming problems associated with Climate Change and our crisis of biodiversity.
Fall in love with every Monarch you see.
Afterward: In an effort to trace the migration of Monarch butterflies, citizen scientists (including children) are encouraged to collect, tag, release, and report on monarchs in their respective areas. Although well-intentioned, I am disturbed by this practice because there are studies that indicate that when Monarchs are captured and held by humans their hearts race and they exhibit a high stress level. Creating more stress for an insect who has to make an arduous fall journey to the mountains of Mexico is not something I would feel comfortable doing. This practice may be useful for people who need statistics to tell them how fast these beautiful butterflies are disappearing, or whether one butterfly made a successful journey, but who is asking the Monarch how it experiences this invasion?
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