Sunday, October 15, 2006

Guided by a mysterious hand?

DONALD G. McNEIL Jr. NYT News Service
A daughter born on a Texas prairie goes on to lay an egg on a South Dakota highway divider that becomes a granddaughter. The great-granddaughter born in a Winnipeg backyard finds her way back to the grove in Mexico that sheltered her great-grandmother. How do the Monarch butterflies do it?

Pinching a bright orange butterfly in one hand and an adhesive tag the size of a baby's thumbnail in the other, the entomologist bent down so his audience could watch the big moment.

"You want to lay it right on this cell here, the one shaped like a mitten," the scientist, Orley R. Taylor, told the group, a dozen small-game hunters, average age about 7 and each armed with a net. "If you pinch it for about three seconds, the tag will stay on for the life of the butterfly, which could be as long as nine months."

Taylor, who runs the Monarch Watch project at the University of Kansas, is using the tags to follow one of the great wonders of the natural world: the annual migration of monarch butterflies between Mexico and the United States and Canada.

The northward migration this spring was the biggest in many years, raising hopes of butterfly enthusiasts throughout North America. But a drought in the Dakotas and Minnesota meant that not nearly as many butterflies started the return trip. And without the late-summer hurricanes that normally soak the Texas prairies and sprout the nectar-heavy wildflowers where the monarchs refuel, many are presumably finding that leg of the journey a death march. Taylor has already halved his prediction for the size of the winter roosts in central Mexico, to 14 acres from 30.

Nevertheless, the 4,000-mile round trip made by millions of monarchs holds a central mystery that Taylor and a network of entomologists are trying to solve.

The butterfly that goes from Canada to Mexico and partway back lives six to nine months, but when it mates and lays eggs, it may have gotten only as far as Texas, and breeding butterflies live only about six weeks. So a daughter born on a Texas prairie goes on to lay an egg on a South Dakota highway divider that becomes a granddaughter. That leads to a great-granddaughter born in a Winnipeg backyard. Come autumn, how does she find her way back to the same grove in Mexico that sheltered her great-grandmother?

Wildebeest, in their famous migration across the Serengeti, learn by following their mothers -- or aunts, if crocodiles get Mom. But the golden horde moving south through North America each fall is a throng of leaderless orphans.

Birds orient themselves by stars, landmarks or the earth's magnetism, and they, at least, have bird brains. What butterflies accomplish with the rudimentary ganglia filling their noggins is staggering.

They are one of the few creatures on earth that can orient themselves both in latitude and longitude – a feat that, Taylor notes, seafaring humans did not manage until the 1700s, when the clock set to Greenwich Mean Time was added to the sextant and compass.

All monarchs start migrating when the sun at their latitude drops to about 57 degrees above the southern horizon.

But those lifting off anywhere from Montana to Maine must aim themselves carefully to avoid drowning in the Gulf of Mexico or hitting a dead end in Florida. The majority manages to thread a geographical needle, hitting a 50-mile-wide gap of cool river valleys between Eagle Pass and Del Rio, Texas.

To test their ability to reorient themselves, Taylor has moved butterflies from Kansas to Washington, D.C. If he releases them right away, he said, they take off due south, as they would have where they were. But if he keeps them for a few days in mesh cages so they can see the sun rise and set, "they reset their compass heading," he said. "The question is: How?"

The skill is crucial because of storms. For example, 1999 was a banner year for monarchs on the East Coast; they were blown there by Hurricane Floyd.

Barrie Frost, a professor of neuroscience at Queens University of Canada, is fairly certain that they don't use the earth's magnetic field or the sky's polarized light. He builds butterfly flight simulators, big barrels open to filtered sunlight with an airflow that a butterfly must navigate with a tiny wire glued to it. Computers sort out the random flitting to say which direction they were aiming for. Repolarizing the light or flipping the magnetic field with a coil does not redirect them, he said.

Frost believes that sun reckoning launches the monarchs generally only to the south, while mountain chains and the Gulf of Mexico funnel them toward southern Texas.

But once in Mexico's mountains, they gain elevation and make several sharp turns. Frost suspects that they are guided by the smell of the previous year's corpses.

Taylor disagrees. Butterflies don't have the odiferous fatty acids that would survive for a year, he said. Disputing the "funneling" theory, he points out that the butterfly biologist William H. Calvert has shown that most monarchs cross central Texas, and his own work has shown that a monarch tagged near the Atlantic or the gulf is only one-tenth as likely to reach Mexico as one tagged in the Great Plains.

The bad news about this year's migration may be temporary, but butterflies also face longer-term threats.

Jeffrey Glassberg, president of the North American Butterfly Association, remembers much bigger flocks as recently as the 1980s. "The whole coast of Staten Island turned orange with butterflies," he said.

Shifting seasons

Global warming is shifting the seasons for the wildflowers. New herbicide-resistant strains of corn and soybeans are letting farmers kill off more milkweed patches. Monarch caterpillars eat only milkweed, which contains a poison that makes birds retch. Just like the bright colors of poison frogs, the monarch's glowing orange markings warn predators that they will regret their dinner.

To get more milkweed sprouting and to support his research ("it's terrific data, but it's bankrupting me, and we're not in a part of the country where philanthropy is easy"), Taylor sells packets of seed for what he calls monarch way stations. He has recruited people to create nearly 1,000 way stations.

The tagging event for families here was part of a much larger effort. Taylor gives out more than 150,000 numbered tags each year to butterfly enthusiasts from the Rockies to the Atlantic. In winter, he goes to the Transvolcanic Mountains in Mexico and spreads the word that he will pay $5 for each one found. That amount, about half a day's pay for a laborer, is enough to make families spend hours sifting piles of dead butterflies beneath the fir trees where the monarchs roost, semidormant in the chilly fogs at 10,000 feet.

The biggest threat to the migration, said Lincoln P. Brower, a biologist at Sweet Briar College and one of the world's foremost monarch experts, is the steady attrition of forests because of illegal logging.

"It's unconscionable," Brower said. "It's like mining the Old Faithful geyser for its gypsum. If it isn't stopped, I'm afraid the whole migration will unravel."


Butterfly Biodiversity in Britain

Menendez, R., Gonzalez-Megias, A., Hill, J.K., Braschler, B., Willis, S.G., Collingham, Y., Fox, R., Roy, D.B. and Thomas, C.D. 2006. Species richness changes lag behind climate change. Proceedings of the Royal Society B 273: 1465-1470.

There have been many sensationalist claims that CO2-induced global warming will drive innumerable species of plants and animals to extinction. However, as we demonstrate in The Specter of Species Extinction: Will Global Warming Decimate Earth's Biosphere?, such statements are based on an incomplete understanding of many pertinent phenomena; and when these other pieces of knowledge are considered, we find that the opportunity that is provided by warming for species to expand their historical ranges poleward in latitude and upward in altitude, together with the demonstrated propensity for many species to not be forced to abandon equivalent areas of the warmer parts of their ranges (particularly when the air's CO2 content rises concurrently), leads to a greater overlapping of species' ranges and concomitant increases in local biodiversity throughout the world.

What was done
In an important study of this subject, Menendez et al. "provide the first assessment, at a geographical scale, of how species richness has changed in response to climate change," concentrating on British butterflies. This they do by testing "whether average species richness of resident British butterfly species has increased in recent decades, whether these changes are as great as would be expected given the amount of warming that has taken place, and whether the composition of butterfly communities is changing towards a dominance by generalist species."

What was learned
The nine UK scientists determined that "average species richness of the British butterfly fauna at 20 x 20 km grid resolution has increased since 1970-82, during a period when climate warming would lead us to expect increases." They also found, as expected, that "southerly habitat generalists increased more than specialists," which require a specific type of habitat that is sometimes difficult for them to find, especially in the modern world where habitat destruction is commonplace. In addition, they were able to determine that observed species richness increases lagged behind those expected on the basis of climate change.

What it means
The results obtained by Menendez et al. "confirm," in their words, "that the average species richness of British butterflies has increased since 1970-82," as our thinking has suggested it should. However, some of the range shifts responsible for the increase in species richness take more time to occur than those of other species; and they say their results imply that "it may be decades or centuries before the species richness and composition of biological communities adjusts to the current climate."

Reviewed 11 October 2006


Monday, October 02, 2006

City’s ‘butterfly man’ has stamped his mark on the world

Anupam Bhagria

Ludhiana, September 15: S K Sondhi can rightly be called the “butterfly man”. As you enter his house, you get the impression that you are entering a butterfly museum. From wind chimes to decorative objects – every item bears the impression of butterflies.

A philatelist of international fame, Dr Sondhi retired as Dean of College of Agricultural Engineering from Punjab Agricultural University on August 31. But he insists that he has retired from his profession “but not from my hobby of philately. I will spend more time to pursue my hobby.’’

Dr Sondhi has been collecting his stamps from the tender of 10 after he received a gift of postage stamps and album from his cousin. ‘‘There were three D stamps of Bhutan which hooked me to this hobby. And I started collecting stamps on theme ‘Butterfly’ when I was in Class 10.”

Why butterfly? No specific reason, he says. But today he has more than 5,000 stamps on butterflies, which he has been displaying at national and international exhibitions.

He has won three national and one international award for this too. ‘‘In June that my exhibit on ‘Blood donation’ got Big Silver medal in international exhibition at Denmark. I have already won one international award and one national award for this too,’’ he says. A lot of hard work is behind this.

“I read dozens of books on butterflies including dictionaries and encyclopedia. I have 90 per cent collection of stamps on butterflies”.

His stamps on butterflies tells the whole story: species, body parts, habitats, life cycle, migration, predators, survival strategies, folklores, costume… everything.

Stamps are just one manifestation of Dr Sondhi’s love for butterflies. He has coins of West Indies having butterfly impressions. There are dozens of phone cards having butterflies photos, wall hangings of dead butterflies, and the photographs of every butterfly in the ‘Butterfly Zoo’ at Niagra Falls in Canada.

This butterfly lover is the founder president of Ludhiana Philately Club and worked as president from 1973 to 1981. He also wrote a book and edits ‘The North Post’ - the magazine of Ludhiana Philately Club, which won a medal in literature class at National Philatelic Exhibition in 1993 in Kolkata. He is also a member of the governing council, Philatelic Congress of India for over 10 years.

His wife Sushma, a school teacher, maintains that “Philately is the first wife of Dr Sondhi. I am the second. But she said she has always inspired his hobby.”

About future plans, Sondhi says: ‘‘Butterflies to meri hain hi’. But I have also planned to collect stamps on ‘AIDS Awareness’ and ‘Road Safety.’’

He is also willing to organise workshops and seminars in schools, and “I have plans to establish a philately library at the Head Post office.”