Missing Monarchs and Marvelous Milkweed

Monarchs depend on milkweed for their survival. Sid Mosdell, SidPix. Monarch on Milkweed. CC. https://www.flickr.com/photos/sidm/4439745304/

Monarchs depend on milkweed for their survival. Sid Mosdell, SidPix. Monarch on Milkweed. CC.
https://www.flickr.com/photos/sidm/4439745304/

The first time I saw a Monarch butterfly lazily flitting through suburban Ottawa, I was flabbergasted! For me, Monarch butterflies were the poster child of metamorphosis, and I had finally met my childhood icon! Growing up in bone-dry Calgary was not a great place to see monarchs.

Unfortunately, I may not be seeing many monarchs in Ottawa this summer. Monarch populations were estimated to have declined by 90% this last year, according to Ryan Norris, researcher at the University of Guelph.

Why are Monarchs disappearing? For a long time scientists believed that it was because the forests in Mexico where they overwinter were being destroyed. However, a study published this week proposes that the real problem is the destruction of milkweed in North America, especially in the Mid-Western United States.

So to save the monarchs, we need more milkweed. But what is milkweed, exactly?

Well, as its name implies, it is an aggressive plant that is really good at invading fields and gardens. There are 14 species native to Canada. It likes bright open areas, like those opened up by agriculture and urban development. Under the Ontario weed act, milkweed is a noxious weed.

Milkweed is very good at being a noxious weed. Its seeds fly 7.5-30 meters away from the host plant, invading new territories far away. At the same time, it’s also working underground, sending out roots that will turn into new plants. Soon a colony of clones pop up, ready to dominate the landscape. Muuahhahaa! No, seriously. Milkweed are really good at crowding out other plants. Oh, and milkweed is also toxic to most animals, including humans.

Sounds pretty awful, doesn’t it?

It is if you’re a farmer. Milkweed often competes for space with their crops. Farmers have used herbicide to get rid of milkweed to make room for more farms. Due to industrial farming, milkweed cover declined by 21% between 1995 and 2013.

But milkweed isn’t all bad. In fact, it does a lot of good. As we’ve seen, milkweed is essential for the survival of Monarch butterflies. They depend on milkweed to shelter their eggs and feed their caterpillars. In fact, milkweed is the only thing that monarch caterpillars will eat. Species like Milkweed Bugs and Milkweed Leaf Beetle are also strict milkweed eaters.

In addition, milkweed plants are super cool! Here are some reasons why.

1.They have complex and clever flowers

Individual milkweed flowers are very complex! Photo by Jason Hollinger. CC.https://www.flickr.com/photos/7147684@N03/1035856056/

Individual milkweed flowers are very complex! Photo by Jason Hollinger. CC.https://www.flickr.com/photos/7147684@N03/1035856056/


Milkweed blossoms may look like pink pom-poms, but they have an ulterior motive: trick insects into carrying their pollen. Unlike most plants that reproduce using loose pollen grains, milkweed store their pollen into special sacks called pollinia. When a bee comes to sip some sweet nectar, one of its legs slips into a hidden slit in the flower where the pollinia is stored. The pollinia attaches itself to the bee’s leg and is carried to the next flower. Very clever!

However, sometimes the insect’s legs get stuck in these slits and they are trapped forever and die among the flowers. Unlucky for them, but lucky for the hungry predators that lurk among the leaves.

2.They are living grocery stores

Milkweed is one of my favorite summer flowers because it attracts so many insects. Monarch caterpillars and Milkweed bugs munch away at the poisonous leaves, becoming poisonous themselves to ward off predators. These poisons are called cardiac glycosides. Don’t eat the plant or get the sap in your eyes, because it’s also toxic to humans!

Crazy fact. Even though the milkweed’s sap is poisonous, the nectar and pollen in the flowers are not. So the milkweed gets the best of both worlds: lots of things want to pollinate its flowers, and very few things want to eat its leaves. Genius!

Milkweed flowers can be seen from June to August. Many species pollinate these flowers, including bees, wasps, butterflies, ants and even hummingbirds.

However, danger can be lurking for these peaceful pollinators. Some predators like crab spiders and Yellow Jackets hide in the large leaves of the milkweed and pounce on the pollinators as they come by to sip nectar. So predators think milkweed is pretty cool too!

3.They have silky seeds

Milkweed pod bursting with silky seeds. Photo by liz west, Muffet. Milkweed seeds2. CC. https://www.flickr.com/photos/calliope/58266084/

Milkweed pod bursting with silky seeds. Photo by liz west, Muffet. Milkweed seeds2. CC.
https://www.flickr.com/photos/calliope/58266084/


The fluffy silk that milkweed uses to spread its seeds has definite entertainment value. It’s like blowing a dandelion, but 10 times better! However, there are practical uses too. Every thread of silk is a tiny, air-filled tube with great insulation and flotation properties. Hummingbirds use it to line their nests to keep their babies warm. In World War II, milkweed silk was used to fill life jackets when they ran out of kapok, another fluffy plant fibre. Recently, milkweed has been grown commercially as stuffing for hypoallergenic pillows.

Milkweed is a pretty cool plant, especially because Monarchs need it to survive. You can help increase milkweed populations by planting it in your garden. You’ll see lots of amazing insects flocking to your garden in no time!

Sources

http://www.thestar.com/news/canada/2014/06/04/monarch_butterfly_decline_due_to_loss_of_milkweed_new_study_shows.html
http://www.uoguelph.ca/news/2014/06/habitat_loss_on.html
http://www.fcps.edu/islandcreekes/ecology/common_milkweed.htm
http://www.britannica.com/EBchecked/topic/99429/caterpillar#ref1078198
http://kids.britannica.com/comptons/article-9275841/milkweed
http://kids.britannica.com/comptons/article-9275229/kapok
http://dnr.wi.gov/org/caer/ce/eek/teacher/milkweedmonitoring/milkweedfacts.pd
http://www.butterflyencounters.com/milkweed-facts.html
http://www.monarchwatch.org/milkweed/index.htm
http://www.monarchwatch.org/milkweed/prop.htm

http://www.monarchwatch.org/read/articles/canweed2.htm
http://www.sciencedirect.com/science/article/pii/S0926669006001270

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About Amelia

I am a recent biology graduate and current journalism student exploring career opportunities in science communications.

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