Richard Weber: Butterfly magic
The annual migration of the monarch butterfly is one of the most amazing events in all nature, and you can catch a bit of the magic by keeping an eye out for these black and orange butterflies as they make their way across Kansas.
If you see one you will probably see another, for these solitary insects become more social during fall migration. Look for the “roosts” where they gather in large numbers to rest on their long journey south. They often roost in the same trees from one year to the next.
This migration is a story of nature’s remarkable capacity to solve seemingly unsolvable problems, and the tale begins in a puzzle of how a creature that small could complete such a difficult journey.
It’s as if you were to build a flying machine weighing half a gram, attach some fragile wings and send it on a 2000-mile journey through an atmosphere blooming with wind, rain and violent storms. No engineer in his right mind would expect an experiment like that to succeed.
But succeed it does, and every year millions of butterflies arrive safely at their wintering ground in the mountains of central Mexico.
Migrating monarchs have to solve two major problems, and the first is knowing where to go. But none of them have ever been to Mexico and they never saw another butterfly that had been there. It takes four generations to complete the full cycle.
Apparently, the wintering site is fixed in their brain and passed on from one generation to the next. How that came to be is one of the marvels of evolution.
Aside from knowing the destination, the butterflies also have to know how to get there. To solve that problem, they use the sun as a compass. But the sun keeps changing its position through the day and compensating for that movement requires an accurate clock.
Just such a clock has been located in the brain of a monarch, and it is composed of four cells. It’s those four little cells that make much of the magic happen.
Monarch butterflies also have an uncanny sense of place. They always seem to know where they are, as if nature had provided them with a map of North America. For example, North Dakota monarchs know they have to fly south to get to Mexico, and those in Georgia know they have to fly west for a while and then south.
Why do the Georgia butterflies begin by flying west when their wintering site in Mexico lies southwest of the state? The answer is, by flying southwest they would have to cross the Gulf of Mexico and they couldn’t survive the long flight over open water.
Again, none of those butterflies have ever seen the Gulf of Mexico, and yet they somehow seem to know it’s there.
The migration of the monarch butterfly is a perfect example of what Richard Dawkins called “poetic magic.” It is not fairytale magic but the magic of a reality that evokes deep emotion and leaves you with the feeling of having experienced something quite extraordinary.
Richard Weber is a nature enthusiast who lives in the country near Ellis. Reach him at email@example.com