25 June 2008


Slate Magazine
green room
A Tick's Life
The first in a series on revolting creatures.
By Constance Casey
Posted Tuesday, June 24, 2008, at 8:04 AM ET

Ticks, which live on blood and nothing but blood, are loathsome to us. We strongly prefer not to share our blood, unless the act is voluntary and we get juice and doughnuts afterward.

It's good that ticks are loathsome, because getting them detached from us as quickly as possible is the best way to avoid being infected by the diseases they carry. Ticks not only extract blood, they ooze pathogens from their salivary glands into the wound they've sliced with their tiny claws and penetrated with their barbed mouthparts. Normal human beings don't sit around and watch with interest for days and days as this process takes place. (Undisturbed, a tick could happily sup for up to a week.)

It's generally known the danger these small creatures pose, particularly the deer tick—Ixodes scapularis. This tick's saliva is the medium for delivery of a particular spirochete, or corkscrew-shaped bacterium, called Borrelia burgdorferi—famous for causing Lyme disease. I managed to locate Willy Burgdorfer, the scientist who identified the Lyme spirochete in 1982, and asked, "Why did God make ticks?"

"I don't have the answer," Dr. Burgdorfer said. "There are a lot of things we assign to the good Lord and we ask the question, why? All I can advise is to check yourself for ticks and remove them fast."

We know about the tick's danger to us, but we haven't thought much about how the ticks themselves survive life's competitive drama—how they reproduce and how they die.

The tick's life is simple, fairly boring, but urgent. No host, no blood meal, and the tick dies. There's only one blood meal for each of the three stages of a tick's life—larva, nymph, and adult. At each stage, every one of the tick's behaviors has been honed by evolution to sense a victim and latch on.

Deer ticks don't find the mice, deer, or us by sight; they have no eyes. On the tips of their front legs they have sensors, the Haller's organs, that allow them to detect, from as far away as a few yards, the heat given off by warm-blooded animals and the molecules of carbon dioxide that we mammals exhale. Blow into a tube of ticks at a lab, and you'll see them begin to wave like excited fans at a Justin Timberlake concert.

Exhale on those other bloodsuckers, fleas, and they jump. The good news about ticks is that they cannot jump or fly. The bad news is that if you find a tick on your scalp, it has probably crawled up your body from about sock-top level. Ominously, the Centers for Disease Control and Prevention advises us to check for ticks between our legs and then in the belly button.

When the "mammal nearby" message is received, a tick's two front legs, equipped with claws that act like grappling hooks, thrust into the air while its three pairs of back legs hold on to a blade of grass, a twig, or a leaf. (Ticks are arachnids, with eight legs, in the family of spiders, scorpions, and mites. Insects have six legs. If you want to impress tick researchers, tell them that you know a tick in larva stage has only six legs.) A host brushes against a tick, and the tick hitches a ride.

He or she roams for a few hours looking for the right spot to attach. Then the two claws make the incision, and in goes the hypostome, shaped like a harpoon, with backward-facing barbs.

The tick then secretes a cementlike substance from its mouth, which glues it to the host and dissolves days later when the tick is sated and ready to drop off. Tick saliva also contains an anticoagulant to keep a host's blood flowing.

There they are, imbibing and drooling; it's the drooling that puts us at risk. Perhaps we should sympathize because the tick itself is a host. (We, too, by the way, carry spirochetes—harmless ones, in our mouths.) The parasitic spirochete sits in the tick's midgut until the blood flows in. Then, stimulated by the blood's nutrients and warmth, the newly expanded crowd of spirochetes migrates to the tick's salivary glands.

Entomologists estimate it takes more than 24 hours for the spirochete to move up and out, thus the importance of checking your body for embedded ticks and removing them as soon as possible.

An adult tick isn't as dangerous to us as a nymph, which is tiny enough to be mistaken for a freckle on light skin. The tiny adolescent is also likely to have fed on a mouse, the most efficient reservoir for the dangerous spirochete. (Though heavily infested with B. burgdorferi, mice don't get sick. In any case, no one has heard mice complain of fever, aching joints, fatigue, rash, and mood disorders.)

The male adult tick expands his repertoire to include finding females. He looks, logically enough, on the biggest moving mammalian blood supply around—a deer. Deer are in one way relatively innocent in the Lyme disease story—they have components in their blood that prevent the spirochetes from surviving. But they are also orgy enablers; if there were fewer deer, there would be fewer ticks, because the ticks would have a harder time finding one another.

Male and female engage in an impressive combination of gourmandise and lust. Maybe not lust exactly; for the female, it's more like being interrupted at breakfast by the UPS guy, with a package of perishables. Here's the setup: The female has her hypostome planted in the deer, imbibing. A long meal is the cue to her body to produce her 2,000 or so eggs. The male approaches from below, then uses his mouthparts to pluck a packet of sperm called a spermatophore from his genital pore. He delivers the packet into his partner's genital pore with his hypostome, the same barbed hollow needle that he sticks into mammals. The male frequently remains attached, mouthparts locked in the female genital aperture, to prevent other males from linking up with his chosen mate. After the female drops to the ground, full of blood and sperm, she lays her eggs, and then the fun is definitely over. She begins to atrophy. Her intestines spill out in a yellow blob. "When does the male die?" I asked Durland Fish, who studies tick-borne pathogens at the Yale University School of Public Health. "When he runs out of energy or sperm, whatever comes first," Dr. Fish replied.

So death for the tick comes from starvation, dehydration, egg-laying, or old age, rather than from predation. We don't seem to have any natural allies in tick control. It's not well known what kind of animal eats ticks, though the larvae are vulnerable to fungi. Dr. Fish scornfully dismissed the guinea hen as a form of pest control—"a Christie Brinkley-ism." (The former model advocates buying a flock of the cackling black-and-white birds to clear your yard of ticks.)

I repeated the question of why God made ticks for Dr. Fish. He responded with a growl to what he took to be my facetious tone: "Nobody makes them. They're just there. Their object, like ours, is to make a living any way they can."

And the tick's place in the great web of life? "They transmit disease. They control population."

"Including us?" I asked.

"Whatever is susceptible to the disease."

Next installment: Vultures!
Constance Casey, a former newspaper editor, was a New York City Department of Parks gardener for five years. E-mail gardening questions to gardening@slate.com.

Article URL: http://www.slate.com/id/2193879/

18 June 2008

not the banana!

from today's nytimes...
Yes, We Will Have No Bananas

Article Tools Sponsored By
Published: June 18, 2008

ONCE you become accustomed to gas at $4 a gallon, brace yourself for the next shocking retail threshold: bananas reaching $1 a pound. At that price, Americans may stop thinking of bananas as a cheap staple, and then a strategy that has served the big banana companies for more than a century — enabling them to turn an exotic, tropical fruit into an everyday favorite — will begin to unravel.

The immediate reasons for the price increase are the rising cost of oil and reduced supply caused by floods in Ecuador, the world’s biggest banana exporter. But something larger is going on that will affect prices for years to come.

That bananas have long been the cheapest fruit at the grocery store is astonishing. They’re grown thousands of miles away, they must be transported in cooled containers and even then they survive no more than two weeks after they’re cut off the tree. Apples, in contrast, are typically grown within a few hundred miles of the store and keep for months in a basket out in the garage. Yet apples traditionally have cost at least twice as much per pound as bananas.

Americans eat as many bananas as apples and oranges combined, which is especially amazing when you consider that not so long ago, bananas were virtually unknown here. They became a staple only after the men who in the late 19th century founded the United Fruit Company (today’s Chiquita) figured out how to get bananas to American tables quickly — by clearing rainforest in Latin America, building railroads and communication networks and inventing refrigeration techniques to control ripening. The banana barons also marketed their product in ways that had never occurred to farmers or grocers before, by offering discount coupons, writing jingles and placing bananas in schoolbooks and on picture postcards. They even hired doctors to convince mothers that bananas were good for children.

Once bananas had become widely popular, the companies kept costs low by exercising iron-fisted control over the Latin American countries where the fruit was grown. Workers could not be allowed such basic rights as health care, decent wages or the right to congregate. (In 1929, Colombian troops shot down banana workers and their families who were gathered in a town square after church.) Governments could not be anything but utterly pliable. Over and over, banana companies, aided by the American military, intervened whenever there was a chance that any “banana republic” might end its cooperation. (In 1954, United Fruit helped arrange the overthrow of the democratically elected government of Guatemala.) Labor is still cheap in these countries, and growers still resort to heavy-handed tactics.

The final piece of the banana pricing equation is genetics. Unlike apple and orange growers, banana importers sell only a single variety of their fruit, the Cavendish. There are more than 1,000 varieties of bananas — most of them in Africa and Asia — but except for an occasional exotic, the Cavendish is the only banana we see in our markets. It is the only kind that is shipped and eaten everywhere from Beijing to Berlin, Moscow to Minneapolis.

By sticking to this single variety, the banana industry ensures that all the bananas in a shipment ripen at the same rate, creating huge economies of scale. The Cavendish is the fruit equivalent of a fast-food hamburger: efficient to produce, uniform in quality and universally affordable.

But there’s a difference between a banana and a Big Mac: The banana is a living organism. It can get sick, and since bananas all come from the same gene pool, a virulent enough malady could wipe out the world’s commercial banana crop in a matter of years.

This has happened before. Our great-grandparents grew up eating not the Cavendish but the Gros Michel banana, a variety that everyone agreed was tastier. But starting in the early 1900s, banana plantations were invaded by a fungus called Panama disease and vanished one by one. Forest would be cleared for new banana fields, and healthy fruit would grow there for a while, but eventually succumb.

By 1960, the Gros Michel was essentially extinct and the banana industry nearly bankrupt. It was saved at the last minute by the Cavendish, a Chinese variety that had been considered something close to junk: inferior in taste, easy to bruise (and therefore hard to ship) and too small to appeal to consumers. But it did resist the blight.

Over the past decade, however, a new, more virulent strain of Panama disease has begun to spread across the world, and this time the Cavendish is not immune. The fungus is expected to reach Latin America in 5 to 10 years, maybe 20. The big banana companies have been slow to finance efforts to find either a cure for the fungus or a banana that resists it. Nor has enough been done to aid efforts to diversify the world’s banana crop by preserving little-known varieties of the fruit that grow in Africa and Asia.

In recent years, American consumers have begun seeing the benefits — to health, to the economy and to the environment — of buying foods that are grown close to our homes. Getting used to life without bananas will take some adjustment. What other fruit can you slice onto your breakfast cereal?

But bananas have always been an emblem of a long-distance food chain. Perhaps it’s time we recognize bananas for what they are: an exotic fruit that, some day soon, may slip beyond our reach.

Dan Koeppel is the author of “Banana: The Fate of the Fruit That Changed the World.”

11 June 2008


the green lantern
Bamboo and You
Are hardwood floors a crime against the Earth?
By Brendan I. Koerner
Posted Tuesday, June 10, 2008, at 7:26 AM ET

A flooring salesman recently tried to sell me on the greenness of bamboo. He claimed that producing bamboo planks is more sustainable than the methods used to create oak or maple floors. Is there really that much of a difference?

Bamboo does have loads of green potential. But as is usually the case when it comes to crops, much depends on how the bamboo is managed, harvested, and ultimately made into flooring. Many producers assume that consumers won't pay attention to such behind-the-scenes details and will be dazzled by smooth-talking salesman who toss around words like "sustainability" and "sequestration." It's up to you to do your homework and avoid being cajoled in such a manner.

As most Botany 101 students learn, bamboo is widely regarded as one of the planet's fastest-growing plants—some species can grow up to three feet in a single day. That means that the plants can be harvested and regrown in a jiffy: A bamboo plant reaches full maturity within three to five years, versus 40 to 50 years for many species of hardwood trees. If culled correctly, so that a viable portion of the stalk and roots remain, the bamboo needn't be replanted; it can simply regenerate.

According to bamboo advocates, this rapid cycle translates into increased carbon sequestration, since fast growing trees (such as the eucalyptus) absorb carbon more quickly than the likes of oaks and pines. (Though it's technically a grass, bamboo is usually compared to trees because of its woodlike properties.) The World Wildlife Federation estimates that an acre of bamboo can store 6.88 metric tons of carbon per year, about 70 percent more than an acre of hardwoods. If that bamboo is turned into flooring or furniture that won't rot due to the treatments applied, then that carbon can remain fixed for decades.

The last point in bamboo's favor is its robustness. The plant will grow in a variety of climates and soils and can flourish unaided by chemical fertilizers, pesticides, or gas-guzzling machinery. Bamboo producers also claim that the plant's extensive root systems prevent soil erosion, though the Lantern has yet to see evidence supporting this contention from sources uninvolved in the flooring trade.

But bamboo's environmental edge can evaporate if the stuff is heedlessly grown. Given the recent vogue for bamboo among Western consumers, producers in Asia (specifically China's Hunan Province) have been aggressive with their planting, often at the expense of old woodlands and their attendant ecosystems. To goose their yields, these plantations employ plenty of fertilizers and pesticides, thereby negating one of bamboo's primary advantages. And when the bamboo is converted into planks, the factories often use glues with high levels of formaldehyde, which can have serious health consequences for consumers (particularly those with asthma or severe allegies). Reading the label usually can't shed much light on these concerns. There just isn't much international oversight of China's bamboo plantations. While there are plenty of hardwood operations whose sustainability is verified by the Forest Stewardship Council, the Lantern knows of only one bamboo flooring company that has obtained FSC certification.

Manufacturers of hardwood flooring also point out that bamboo planks cause lots of fossil-fuel emissions when they're transported to the United States from China. The Lantern isn't totally swayed by this line of argument, however: While giant container ships certainly burn tons of fuel, they are also fairly efficient due to their massive capacities. (The shipping company Maersk, citing Sweden's Network for Transport and the Environment, contends that its ships are actually cleaner than trains, trucks, or cargo planes.) As a result, your specific geographic location will play a role in your flooring's transportation-related impact. If you live in California, shipping bamboo from China may result in less fossil-fuel consumption than, say, trucking in maple flooring from the Northeast.

The bottom line is that the onus is on you to ask questions before you fork over thousands of dollars for new flooring. Don't automatically assume that bamboo is the environmental winner, especially if there's a locally sourced, FSC-certified hardwood option. If you are tempted by bamboo, don't settle for the salesman's patter about his product's wonders—get in touch with the manufacturer and inquire about how the source material is raised and harvested. Some of the greenest bamboo doesn't come from monoculture plantations but, rather, from operations such as Madagascar Bamboo, which harvests naturally occurring plants from the edges of farms. (The farmers used to think of the bamboo as a valueless annoyance.)

Also look into whether the floors use low-formaldehyde glue. Don't be shy about asking for test results—reputable flooring companies should offer glues that emit less than 0.01 parts per million of the substance. (You'll probably have to pay around 75 cents more per square foot for such flooring, but it may be worth it.)

Above all, be sure to walk on an installed bamboo floor before forking over your hard-earned cash. There is a lot of variety in the feel of bamboo flooring, depending on how carefully the material has been treated and the finish applied. You want to make sure you're laying down planks that will grace your home for decades, not something you'll simply rip up in favor of maple five years down the line. As always in environmental quandaries such as these, the greenest decision is the one that will result in the least amount of turnover.

Is there an environmental quandary that's been keeping you up at night? Send it to ask.the.lantern@gmail.com, and check this space every Tuesday.
Brendan I. Koerner is a contributing editor at Wired and a columnist for Gizmodo. His first book, Now the Hell Will Start, is out now.

Article URL: http://www.slate.com/id/2193239/