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  Monarch Butterflies Are in Trouble!

By Shlomo  Maital    

        Monarch 2               

After blogging about the incredible monarch butterly and its 8,000 km. migration,  I am saddened to learn that the Monarchs are in trouble, because of us humans of course.  

    The annual migration south of the butterflies should have brought 60 million of them to their feeding grounds in Mexico. Instead only 3 million have arrived!   Yikes.  Why?

     Partly because farmers use tons of Monsanto’s weed killer Roundup, which kills everything but genetically modified plants, engineered to resist it.  This means it also kills milkweed, which is exclusively what Monarch larvae eat. (Why? As I wrote – to make them poisonous and not tasty for birds). 

    Writing in the New York Times,  VERLYN KLINKENBORG summarizes the terrible threats to the Monarch butterflies:   “For the past 15 years, scientists have been watching monarch numbers plummet, as much as 81 percent between 1999 and 2010. They reached nearly catastrophic lows in the winter of 2009-2010 and have barely recovered since.   One recent study suggests that the long-term survival of the species may be in doubt. A few weeks ago, one of the scientists devoted to studying monarchs, Ernest Williams at Hamilton College, summarized for me the threats that have been reported in recent studies.   Nearly every link in the monarchs’ chain of being, he said, is at risk. Illegal logging in Mexico has reduced their winter habitat — an already vanishingly small area, which is itself being altered by the warming climate. Ecotourists who come to witness the congregation of so many butterflies disturb the creatures they have come to see. But perhaps most damaging is the demise of milkweed. What looks like agricultural success, purging bean and corn fields of milkweed (among other weeds), turns out to be butterfly disaster. This is the great puzzle of species conservation — it has to be effective at nearly every stage of a species’ life cycle. And this, too, is the dilemma of human behavior. We live in a world of unintended consequences of our own making, which can never be easily undone.”

     Over millions of years, Nature has evolved incredibly delicate, complex ecosystems.  When we damage one tiny part of it – a fragile butterly, an amazing bee – the whole system is endangered.  My grandchildren may one day see Monarch butterflies – in museums, on pins.  Alas. 

   

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How a Tiny Butterly Does the Impossible…So Can You!

By Shlomo  Maital    

     Monarch 1  Monarch 2                       

 

   Consider the amazing Monarch butterly, shown above.  They weigh only 0.4 grams  each, on average. This is a bit more than one one-hundredth of an ounce!  Yet they are able to engage in an annual migration of some 8,000 kms. (4,800 miles!).  The trip north to coastal California and Washington from Mexico each spring requires three to four generations, as eggs are laid on the way in spots where milkweed grows, caterpillars emerge, spin chrysalises, and become butterflies. 

   How in the world do light-as-air butterflies manage to fly so far, even through three or four generations?  They are very clever at using updrafts of warm air and air currents.  How do they avoid being eaten, as they fly in large butterly clouds?  Simple.  They eat milkweed.    Milkweed contains a toxic poison. So birds avoid Monarch butterflies, easily identifiable by the coloration, because eating them gives them a stomach ache, which birds learn the hard way.   The toxic poison is called cardiac glycosides, steroids that act like digitalis and stop the heart.  Not only do Monarchs have poison, they concentrate the poison in their wings, where birds tend to attack.  Monarchs have also evolved to mimic the viceroy butterly, in coloration, which is even more poisonous.

   Monarch butterflies live only for about 30 days.  But what a 30 days!  They are the only butterfly to do a north-south migration, flying north in the spring and south toward winter.   They migrate in huge clouds of millions of butterflies, an amazing sight.

     Monarch butterflies evolved through evolution, and are   proof of how wonderfully Nature does experiments that generate incredible creatures.  There are endless miracles like Monarch butterflies.  They should all, together, make us far more respectful of the wondrous planet in which we live,  which alas we seem intent on polluting and ruining.   How much we can all learn from a tiny fragile creature that weighs nothing yet has learned to survive by making an impossibly long journey every year. 

Blog entries written by Prof. Shlomo Maital

Shlomo Maital
September 2019
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