Saturday, March 27, 2010
Visions of Butterflies
“I do not know whether I was then
a man dreaming I was a butterfly,
or whether I am now a butterfly
dreaming I am a man.”
--- Chuang-tzu 369-286 B.C.
With spring comes a flitting about of butterflies and some interesting scientific news about this mystical insect from the University of California. Butterfly experts have suspected for more than 150 years that vision plays a big role in explaining wing color diversity.
Now, for the first time, research led by University of California, Irvine, biologists proves this theory true – at least in nine Heliconius butterfly species. Adult butterflies, Heliconius or not, are amazingly diverse in shape, size, and color. Species are found on every continent, from mountaintops to rain forests to the frozen tundra.
And, given that there are more than 25,000 butterfly species worldwide and probably gazillions of individual insects floating around, how species manage to find each other and mate is perplexing to those of us who lie awake at night worrying about these things.
But, really, the dilemma is a lot like the one humans face, only on a much grander scale. And, a butterfly’s biological clock ticks a whole lot faster than ours. Although my mother used to say “there’s a lid for every pot,” getting down on your knees and digging the dented bugger out of the bottom cabinet is no easy task, which is why I usually put a plate on a pot, but that's a story for another day. The writer M. W. Hungerford may have inadvertently said it best about butterflies in her 1878 novel of Victorian manners, Molly Bawn : “beauty is in the eye of the beholder.”
This new UCI research suggests seeing in a most unexpected way is the butterflies' trick. Researchers Adriana Briscoe, Seth Bybee and colleagues found Heliconius butterflies have a duplicate gene that allows them to see ultraviolet colors and they also have ultraviolet (UV)-yellow pigment on their wings, making it easier to connect.
The researchers conclude this is good for species survival because it leaves more time for reproducing, eating and sleeping. Not unlike their human counterparts once they take their Ray Bans and a few other things off.
Unlike us humans,the butterflies don't “waste their time chasing after the wrong mate,” according to Briscoe, associate professor of ecology and evolutionary biology and lead author of the study, published online recently in the "Proceedings of the National Academy of Sciences."
This behavior has been going on a long time she says, speculating that butterflies developed a copy of their UV-vision gene and began displaying UV-yellow pigment 12 million to 25 million years ago. Of the 25,000 butterfly species in the world, however, only the Heliconius living in the forests of Mexico and Central and South America are known to have this duplicate gene.
“We think that by switching to a new way of making yellow, the mimetic butterfly species were better able to tell each other apart,” Briscoe said. The diverse wing patterns of Heliconius butterflies have generated much scientific interest in recent years, including a genome-sequencing project co-directed by UCI’s Robert Reed, assistant professor of ecology and evolutionary biology.
The American Museum of Natural History in New York has a Butterfly Conservatory and an information rich Web site for those who can’t visit the museum in person. Find it online at http://www.amnh.org/exhibitions/butterflies/
The Journey North Web site tracks the migration of monarch butterflies, which are arriving in California right now at http://www.learner.org/jnorth/tm/monarch/AboutSpring.html