I used to teach at a charter school in the Anacostia neighborhood of Washington, DC. We started in a church but then moved to a renovated building with several floors. One morning, in the middle of a lesson, motion outside drew our eyes to the window of my second floor classroom. Outside were clouds of black and orange wings fluttering by. As a Spanish teacher, I had heard about Monarch migrations before. Their overwintering sites being in Mexico, they are popular insects in Mexican culture. But this was the first time I ever saw the migration in progress, and it was fascinating to both me and my high school inner city teenagers. We immediately looked up a map of the migration, and they were in fact on time for our area.
Monarchs are fascinating insects. There are four to five generations in a year, and only one of those generations makes the migrations south in the fall and north in the spring. How do they know to keep the family tradition alive? It’s an instinct passed through several generations. Adults in summer generations generally live from two to five weeks. It’s the final generation of Monarchs, which emerges in late summer and early fall, that is tasked with migrating from Canada and the northern United States to their overwintering grounds, either in central Mexico for eastern Monarchs or in California for western Monarchs. These migrating adults can live up to eight or nine months and return to their northern spots once the weather is hospitable for the return trip. Millions of Monarchs travel 2500 miles each year for two reasons: They can’t live in the winter conditions of the north and central United States, and the plants they need for larval sustenance are not in the south. They are the only insect to make a trek this length in order to ensure survival.
Recently, Scientific American published an EarthTalk piece on the dwindling populations. See “Royal Descent: Monarch Butterflies Suffer Sharp Drop in Numbers,” which says “Mexico’s National Commission of Natural Protected Areas reports a 59 percent decline in the area of forest there occupied by overwintering monarchs since December 2011. Meanwhile, the World Wildlife Fund (WWF) reports that overwintering populations along the California coast have shrunk from over a million individuals counted at 101 sites in 1997 to less than 60,000 at just 74 sites in 2009.” Quite an alarming descent.
These decreasing population numbers might not seem very concerning overall (we are talking about insects); however Monarchs and other butterflies are important to our ecosystem. They pollinate, or fertilize, many different types of plants so that seeds and fruits are produced. Pollination is vital to both flora and fauna life spans including playing a key role in food productions for most animals. Humans depend on pollinators such as butterflies and honeybees (also threatened) to maintain the biodiversity and life cycles of plants we use for food sources, medicine, and even construction materials. If natural pollination does not occur, then humans will have to take over. In China, for example, the use of pesticides has drastically decreased the bee population. Now humans are required to step in and pollinate thousands of acres of apple and pear orchards by hand.
So what is causing harm to these butterflies?
- Elimination of milkweed and other Monarch food sources. Monarch larvae love their milkweed, but humans do not. Milkweed is often cut down in favor of highways and housing developments. Herbicides used in agriculture damage milkweed, as does increased ozone exposure.
- Deforestation of Monarch roosting sites in Mexico’s mountains. The lumber from oyamel trees is used for housing, and cutting down the trees eliminates roosting sites and creates holes in the canopy that let in winter weather, making the Monarchs vulnerable to freezing temperatures and snow.
- Use of herbicides and pesticides in backyard gardens that kill the butterflies and their food sources. Monarch advocates recognize that it might be difficult to ask people to cut out pesticide use all together, however pushing for more limited use of it is certainly reasonable.
- Wild fires and droughts also impact Monarch populations and travel patterns.
There are several ways that you can get involved with Monarch conservation. Organizations like Monarchwatch.org and JourneyNorth.org provide educational materials about monarch migration and saving the species.
- For you green thumbs, you can help by planting gardens full of native flowers that attract butterflies. Plant milkweed for the larvae. Azaleas, lilacs, daisies, dandelions, and thistle are all good candidates for producing nectar that will attract the butterflies to your backyard. Monarch Watch even does the work for you by putting together seed kits you can purchase to create Monarch waystations of flowers that work like fast food restaurants for butterflies as they head south.
- If you’re science-minded, help track Monarch migrations. Students and regular citizen scientists like you and I can use the Journey North Web site to upload pictures of Monarchs we see on their way north in the spring and south in the fall to a database that, in real time, tracks where the butterflies are in their migration. This migration and other animal migrations also help scientists look at a more global picture of climate change. For example, Monarchs instinctively begin southward migration when the weather starts to cool up north in the fall. Scientists can see trends in climate pattern shifts by tracking migrations start dates. Are the butterflies leaving earlier or later each year?
- Both Monarch Watch and Journey North provide materials that teachers can use in their classrooms to educate students about Monarchs. If you have children in schools, please share these resources with their teachers and ask the schools if there is room in the yards for butterfly gardens that can be used as outdoor classrooms.
Monarchs may be tiny creatures, but they are very important to the big cycle of life and aiding in their survival helps life at every level. I check the Journey North maps of Monarch sightings every spring and fall now, hoping to catch a glimpse of these star travelers passing by my DC home.