Tuesday, May 28, 2013

Delicate Daredevils

If you want to spice up your next fiesta, try discussing the topic of immigration.  Nothing breaks through the crust of dry conversation like a political hot potato.  Immigration has been simmering and spouting on America’s back burner since the Statue of Liberty bid the tired, poor, huddled masses to come.  We didn’t become a ‘melting pot’ without a little heat, after all.  I am not looking to light a fire in this column, but I do want to draw your attention to another population of undocumented immigrants that is literally flying past border security. 
Monarch sipping Zinnia juice.
Note the tattered wings.

Monarch butterflies flash their tiger-colored wings over the Rio Grande with nary a thought to green cards or governments.  They are embarking on a journey no reasonable, safety-conscious human would attempt: 1,600 miles on parchment-thin wings.  Without so much as a map or American Express card, these delicate daredevils take off into the vast unknown.  What could tempt them to throw caution to the wind?  Appetite, of course. 

They’re coming for a North American delicacy: Milkweed (Asclepias sp.).  When mama Monarch finally rests her weary wings on a Milkweed plant, she has more than nectar on her mind: she’s been carrying a load of progeny and it’s time to deliver them.  She lays her eggs (up to 400!) directly on the leaves.  She’s catering to her finicky offspring: milkweed is the only food they’ll eat.  Flattering as this singular affection may be, the plant does not take larval nibbling lying down. 

The Milkweed/Monarch saga is a twisted plot worthy of a James Bond flick.  Milkweed, loaded with booby-traps, carries a license to kill.  Flowing through its veins is a thick, latex sap.  One poorly placed larval bite can open a veritable floodgate of white glue.  Monarch larvae are easily overwhelmed by the surge of goo: those that don’t drown in the flux, often find their mouths glued shut.  Less than one third survive the namesake sap.  Those that live to die another day, learn to carefully deliver a kill bite: they drain the main vein, leaving the foliage defenseless to their feasting. 

Monarch vs. Milkweed.  The battle begins.
Sap is not Milkweed’s only line of protection: its stems and leaves are laced with cardiac glycosides, a toxin capable of killing small vertebrates, like our twitch-whiskered, cottontail friends.  This protection does not slow the Monarch.  In fact, it acts as a backhanded blessing.  The toxins, while not lethal to the butterfly, accumulate in its body, making it unpalatable to predators. 

After months of indiscriminant pruning by ravenous caterpillars, the plant gets the last laugh.  Fresh-from-the-cocoon Monarchs waltz through pollen as they slurp sugary nectar through their proboscis.  Fluttering from blossom to blossom, they jumpstart seed production for the Milkweed’s next generation. 

Last summer I watched a flock of migratory Monarchs settle into the neighbor’s Maple for the night.  The sun had set, but the branches flared to life as orange and black wings flexed open and closed in the dusky light.  I look forward to catching a glimpse of it this year, but Monarch populations are declining as their wild milkweed habitats are disappearing.  You and I can have a directly impact on their survival:

·      Being careful not to destroy stands of Milkweed is essential.  When they are gone, the butterflies will be gone as well. 
·      Incorporating host plants in our landscapes, like Asclepias tuberosa, Butterfly Weed, provides new habitat for Monarchs.  With its bright orange flowers and drought tolerant nature, it’s an Illinois natural. 
·      Avoid pesticide use.  Insecticides kill butterflies and herbicides kill milkweed.    

Pretty pollinators make gardens doubly beautiful and keep those flowers and fruits a-coming.  Let’s do our part to keep these south-of-the-border beauties floating through Kankakee County.

Monarch caterpillar on Butterfly Weed

1 comment:

Casa Mariposa said...

You are one of my favorite writers. :o) I have 2 small stands of asclepias incarnata but have quite a bit of ascl. tuberosa, which takes drier soil and reseeds easily. It's hard for me to keep the swamp milkweed moist enough. I get monarch cats every year, but occasionally the caterpillars form their cocoons so late in the season, they die from frost before they can hatch and migrate. Great post!!

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