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Milkweeds- The Corona Flower

Milkweeds belong to a genus called Asclepias, this genus has some of the most complex flowers in the flower kingdom. They resemble a typical flower but have some very different parts. First thing you will notice is that the flowers form a sphere, called an umbel, at a distance they resemble the corona virus. Interestingly enough, their petals are folded back and are surrounded by a petal like structure called a corona! Corona means “like a crown” so we could say that each flower, and the virus, looks like they are wearing a crown. 

Milkweed flowers

The corona is made up of a hood and a horn. The hood is where the nectar is stored and there is quite a bit of debate about the function of the horn. What I do know is that the horn causes many small insects to lose appendages and sometimes their lives. They get their legs stuck under the horn and end up ripping them off to break free or they die of starvation. Insects also get their legs stuck in the flowers stigmatic slit, which is where the pollen sacs are stored. Those in search of nectar slip their legs into these slits while they are visiting the flower, the pollen sacs stick to their legs and they are taken to another milkweed flower to be pollinated, that is of course, if they can get their legs back out. In order to pollinate a milkweed you need to be a fairly large insect, if not, you risk amputation or even death. 

Fly with its leg stuck in the stigmatic slit

Milkweeds are named as such because of a white latex that is found throughout the entire plant. When you break open any part of the plant it oozes this milky substance. The milk is slightly toxic, containing cardiac glycosides that can make you very sick. These glycosides are actually used in medicines to treat heart failure and irregular heartbeats, but too much can cause a poisonous overdose. So, do not drink the milk of the milkweed.

Oozing latex from milkweed leaf

There are several species of insects that can eat milkweed with no problem at all. The most famous one is the caterpillar of the monarch butterfly. As it eats the toxic milk, it too becomes toxic! A great defense against those that may want to eat them. This process is called bioaccumulation, it’s kind of like- you are what you eat. This same thing happens to other insects that have evolved to eat milkweeds, like the longhorn milkweed beetle. 

Longhorn Milkweed Beetle

The beetles scientific name is Tetraopes tetrophthalmus, meaning four eyed. Interestingly, their eyes are divided in two because their antennae appear to grow right through them! It’s possible that this evolved because their antennae were getting in the way of their eyesight, so they developed eyes on either side of them. The female beetles lay their eggs on the stem near the base of the plant. The larvae hatch, bore themselves into the stem, travel down the stem into the roots where they eat the roots throughout the fall. They over winter in the roots and emerge in the summer right when the milkweeds are flowering- perfect timing. 

You don’t have to go far to see these flowers and appreciate their seemingly menacing characteristics. Visit one and see if you can find any pieces of pour insect souls who are now existing as amputees. 

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