We cannot live in a world where the Monarch Butterfly does not exist. Period. ~ The Adventures of Johnny Butterflyseed
As with many other topics I attempt to address, I knew little about butterflies before I began research for this post. However, I did have one experience with another GSMNP volunteer, Mark Weingartz, when I joined his group to tag* Monarchs. I freely admit I couldn’t even catch a cold that day, but I watched youngsters swing their nets, capturing butterfly after butterfly. I was at least able to learn by watching. Mark gave us a Monarch overview, but these days I have to hear things multiple times and then read about them later to retain anything. Don’t laugh. Some of you are the same way. I know who you are. Here we go.
*Why tag Monarchs? Scientists are still learning about the origins and final destinations of these beautiful winged creatures. When one is tagged in one location and spotted in a completely different region or country, credible data is added to scientists’ body of work.
A little background before we head south
Super generation butterflies are unusual in that they appear only every fourth generation. While their parents, grandparents, and great-grandparents lay eggs within a few days of emerging from the chrysalis, the Super Generation’s reproductive timeframe is much later. Months later. That isn’t the only difference,* though. Monarchs:
- Make an appearance later than others — in August in many U.S. regions
- Don’t lay eggs until they’ve traveled thousands of miles and made the return trip–the following spring.
- Are cold-intolerant. If I return as another species, I might be a Monarch.
- Can’t help themselves; they are travelers.
Boy, are they! When they leave their “birth” area to search for a warmer place to winter, they don’t go local.
*Source Nature Foundation and U.S. Fish & Wildlife Service (https://www.reconnectwithnature.org/news-events/the-buzz/five-facts-monarch-butterfly-super-generation/).
Househunters international--with wings
Monarchs are world-class travelers. That is, they are airborne for around 3,000 miles, usually about 50 miles a day, according to the Nature Foundation, but possibly as much as 100 miles per day. They do rest at night, normally congregating with other butterflies in cedar, pine, or fir trees. Sometimes they roost in the same trees their ancestors had stayed in the prior year. When they reach their final destination, they find their wintering spot and hunker down in oyamel fir forests. Their activities are curtailed in the winter to conserve their fat stores as much as possible. They do have a return flight to manage, after all. In order to just hang out for the winter, they need:
- Cool, but not freezing, temperatures protect energy reserves.
- Protection from predators and the wind is provided by generous vegetation.
- Water sources come from both the fog in the mountains of Mexico and from nearby streams and rivers. Not all Monarchs winter in Mexico; some find other compatible high altitude locations.
- Trees to roost in, perhaps hundreds on a branch.
But wait, how do they know when to go south and when to return? Curiously, two of the components are the same as the triggers for leaves to change color and fall: cooler temps and shortening days, as mentioned in my October 12th post about Fall leaf changes. The third motivation for the migration is the dwindling supply of milkweed, the Monarch’s primary source of food. That may also be the reason Monarchs head back north,* per National Geographic, as it is very likely the reason Monarchs continue to work their way north through the U.S. upon their return
*I was unable to locate any other theories. I suspect that some of my friends will know the answer to this, and if they educate me in this regard, I’ll provide an update.
The path of the monarchs
This map was produced by the Xerces Society for Invertebrate Conservation. Its site provides information on Monarchs, but also contains information on endangered species and ways you can help in conservation efforts.
Other minor Monarch facts
As often happens when I jump into the deep end of a topic, I run across information* I wasn’t expecting. Here are a few items of interest:
- Milkweed contains toxins which are usually kryptonite to Monarch predators, but not all. (National Geographic)
- Among those who manage to overcome the negative characteristics of milkweed are Orioles, ants, wasps, flies, and spiders. Both the caterpillars and the butterflies are at risk. (National Geographic)
- Monarchs are crucial to the ecosystem as they fly across the country, cross-pollinating. (National Geographic)
- A cluster of butterflies is called a roost or a bivouac. (Journey North)
- Monarchs’ greatest threat is loss of food sources. Some of this is due to development of land for farming. That is, some of the land they have been using for their winter habitation is now used for growing avacados. Or something else. And there’s the U.S. problem of a reduction of milkweed availability due to herbicide application and ditch mowing. (Monarch Joint Venture)
- The migration south is not, thank goodness, entirely powered by Monarchs’ wings. They often glide on the air currents. (Nature Foundation)
- Scientists are still researching to learn how Monarchs can find their way to their winter home and back. The current theory is that a combination of the sun’s angle and location over the Earth as well as its magnetic pull might be involved. But they don’t know. (The Nature Foundation)
*Most of the links provided will give you ideas for supporting the Monarch population. That’s one regal group we can all get behind.
Which brings me to – criminy. There is so much I don’t know about topics that I had never before considered. I never cease to amaze myself when it comes to how much more I need to learn. Yes, I know I won’t live long enough to familiarize myself with everything that piques my curiosity. But for as long as I’m here, I’ll soak up what I can to make myself as useful as possible.
You?
