ACT's Nature Corner: The Monarch Butterfly

Most of us recognize the beautiful orange butterfly in our fields and flower gardens, one of the joys of a Maine summer. These amazing insects are unique in many ways, let's discover some of their secrets and learn more about them.

How did the Monarch butterfly get its name?

I love to learn how something has come by its name particularly when it comes with a story or a bit of history. As its name implies the Monarch was supposedly named after a “royal.” It is believed the butterfly was named by North American English colonists to honor a favorite English king; William III who was also known as “William of Orange” who came to power in 1648. How this king came to power is an interesting story for another day. Another interesting tidbit is how we’ve come to use the word “butterfly.” These insects are not flies nor do they have anything to do with butter. In my research, I’ve found that originally they were called “flutterbys” which actually makes a lot more sense as we see them flutter by us. It seemed that the word flutterby was a bit clunky to say and eventually the “fl” and the “b” of flutterby became switched and turned into the word butterfly.

How to tell a female from a male Monarch. When you are watching monarchs try to see if you can tell if it is a male or female. The difference is subtle but once you see it you’ll be able to amaze your friends with your naturalist expertise. See if you can see the difference next time you see one of these beauties. The male monarch has two black spots on its hind wing and the wing veining is thinner.

What’s so special about milkweed and monarchs?

Milkweed is the only food that monarch larva or caterpillars can eat. If there are not enough milkweed plants in our environment then monarchs will not survive. Monarchs have evolved to depend on the milkweed as a particular survival strategy. This plant contains a toxin that has a very disagreeable taste to most animals. The monarch caterpillar however had adapted and can tolerate the toxin which passes into and is stored in its tissues. Predators have discovered that monarchs taste terrible and therefore avoid eating them. Pretty neat trick. It is such a good trick that there is another butterfly called a Viceroy that has evolved to look like a monarch. This is called “mimicry.” The viceroy’s caterpillars never eat the toxic milkweed, but its predators mistake it for a nasty tasting monarch and stay away. As you can see below It looks very much like a monarch but for the horizontal line across the bottom of its wing that is not seen on a monarch.

The life cycle of the Monarch

The monarch has 4 stages of development from an egg to a larva or caterpillar to its pupa stage inside a chrysalis and finally to an adult butterfly. The female monarch lays fertilized eggs on the common milk weed plant. It takes from 3-5 days to hatch. These tiny monarch caterpillars eat only milkweed and go through several moltings or sheddings as they grow over the next two weeks from an 1/8 of an inch to about 3 inches long. They then form a chrysalis. Over the next two weeks the caterpillar transforms into an adult butterfly.

The female butterfly lays her eggs most times on the underside of a milkweed plant after about 4 days the egg hatches into a tiny caterpillar. It begins to eat the milkweed plant voraciously as it grows.

The caterpillar will shed its skin or “molt” about 4 times each time emerging bigger and bigger until it gets to be about 3 inches long and is a beautiful yellow, white, and black eating machine.

After about 2 weeks of eating and growing the caterpillar will begin to do something amazing. It will begin to charge dramatically growing a “chrysalis” or protective covering around and encompassing its body as it enters the pupa stage.

The chrysalis is a gorgeous apple green with dots that appear to be gold. Only 10% of the eggs laid will hatch and only 10% of the caterpillars will live to grow into a Chrysalis. Look carefully under milkweed plants and you may see any of these stages.

Inside the chrysalis the caterpillar is changing into its final stage a butterfly. The chrysalis will also change during this growth, over about 2 weeks, going from the green color to a darker color and gradually becoming transparent where you can actually see the soon to hatch butterfly inside.

Once hatched the butterfly rests and pumps fluid into special tube like veins in its wings which expands and straightens them out. They must still dry before the “flutterby” is able to fly. The monarch is able to fly in an hour or so, but it takes about a full day for the wings to fully harden.

The monarch now begins the cycle of reproduction and life once again, returning to lay more eggs on milkweed plants. As a butterfly, the monarch is no longer tied exclusively to the milkweed for food but feeds on the nectar of all types of flowers. Reproducing monarchs only live between 2 to 4 weeks.

As the summer progresses, daylight shortens, temperatures get cooler, and the quality and quantity of the milkweeds lessen the youngest generation of monarchs do not reproduce but rather spend their time feeding and storing up energy for an incredible journey.

These monarchs join others from across the US and Canada and fly as much as 3000 miles, to the mountainous areas of Mexico the longest journey of any insect. They can fly 50-100 miles a day for up to two months. No one knows for certain how they find their way, but it is thought to be the magnetic field of the earth and the position of the sun. Once at their destination they roost in the oyamel fir forests, clustering in colonies for warmth. When the warm of spring comes to the forest they begin the reproductive cycle once again. New generations are hatched, and it is these generations of monarchs that will fly back for us to enjoy next spring. To learn more about this migration click this link https://www.fs.fed.us/wildflowers/pollinators/Monarch_Butterfly/migration/#:~:text=Using%20environmental%20cues%2C%20the%20monarchs,to%20reach%20their%20winter%20home!

The future for our monarchs - The monarchs have an outstanding story to tell but the sad story is that they are endangered. Habitat loss is the main reason. We have talked about their dependence on one type of plant the milkweed. The amount of milkweed across their range has decreased dramatically. Development is one reason as well as newer agricultural practices. Overall eastern monarchs have decreased by 85% since the mid-1990s. There are important ways you can help. Planting native milkweed in your gardens and fields and help build up their habitat is one of the best. Research and learn other ways to help. Here’s a link to more information. https://blog.nwf.org/2015/02/saving-monarchs/#:~:text=Plant%20Milkweed%20%E2%80%94%20You%20can%20make,species%20native%20to%20your%20area.

It’s up to all of us to see that these beautiful creatures will be around for generations for us to enjoy.