Coping With the Flies of Fall

Coping With the Flies of Fall
New York Times - By MICHAEL TORTORELLO
November 9, 2011

NEARLY a million people live alone in New York City, according to Census Bureau figures. And at one time or another, almost all of them have probably had the same thought: if I die unexpectedly tonight, watching an episode of “The Millionaire Matchmaker,” who will find the body?

A boss? An estranged lover? The pizza delivery guy?

How about a blowfly of the species Phormia regina? A paper published in January in the Journal of Forensic Sciences examined how many days it took for these tiny vultures to alight on a trio of pig carcasses stashed inside a two-bedroom house in Edmonton, Canada. Scientists dressed the pigs in men’s shirts and women’s underwear, opened the windows and cut slits in the screens. For the purposes of comparison, they also left pig corpses outside in the yard.

They did not have to wait long. Flies found the outdoor carcasses almost instantly and began depositing eggs. The indoor cadavers attracted their first flies, by scent, on Day 5 of the experiment.

For the singleton in the city, there are two lessons to take from the Edmonton study: one, find a life partner or a roommate before the flies turn up; and two, fix those window screens, and do it today.

In truth, flies will get into the house no matter what you do. This is especially true in the fall, when flies come in from the cold, said David Grimaldi, 54, curator of entomology at the American Museum of Natural History in New York.

“Right now, people will be noticing an invasion of two types of flies,” Mr. Grimaldi said. “One will be fruit flies, Drosophila, and the other will be cluster flies, Pollenia rudis, which are much larger.” Another frequent party-crasher is the housefly lookalike Musca autumnalis (also known as the face fly, for the way it torments livestock).

“The winter kills a lot of them,” Mr. Grimaldi said. Then, in spring, “there’s a generation, then another generation, then another generation. By the fall, you have quite a population.”

Fruit flies can sneak into the kitchen on an overripe tomato. Cluster flies bask on a warm exterior wall and instinctively climb upward, Mr. Grimaldi said, then wriggle through tiny gaps in the fascia boards or the window frames.

As the eminent British dipterologist Harold Oldroyd wrote in his 1964 classic, “The Natural History of Flies,” “A house or other building is therefore no more than a large fly-trap. It is found that the same building is infested year after year, while the house next door may be immune.”

He added, “At present there is no known remedy for these visitations except to move.”

Flies are, paradoxically, ubiquitous and mysterious. We see them. We hear them. We know next to nothing about them.

If they could talk (and how disturbing would that be?), we would have two questions: What do you want from us? And why won’t you leave us alone?

L IKE a deranged stalker, the common housefly, Musca domestica, wants to be in our company. The feeling is not mutual. At least it wasn’t for Kami Lewis Levin, 35, a curriculum developer and parenthood blogger who returned to New York from Boston in June. Ms. Lewis Levin and her husband were delighted to find a three-bedroom brownstone in Park Slope, Brooklyn, with a backyard and a good school nearby for their two sons.

“It had everything we could possibly want,” she said. And some things they did not want: houseflies by the dozen.

“We didn’t know what to do,” she said. “We did all this Internet research, and everything we read was unhelpful.”

Finally, she settled on flypaper, that sticky spiral found at less reputable food sellers. The traps caught a couple of flies — and a few pieces of Ms. Lewis Levin’s clothing and hair.

“Sometimes it would come off and it would be attached to my face,” she said. “I wouldn’t recommend it.”

She concluded that the only solution was to trace the flies to their source.

Taking the long view — the very long view — her houseflies probably started their journey in the tropics, a few million years ago. Originally, they would have flitted among piles of dung from Old World ungulates like pigs, said Stephen Marshall, 57, an entomology professor at the University of Guelph, in Ontario, Canada. At some point they switched their allegiances to that most clever and restless of great apes, Homo sapiens.

Together, we have colonized the world. Though, to be honest, the fly has not been much help. It breeds in dung or rot, vomits and spits on its food (that is, our food), then sops up the shake with its spongy mouthparts.

Perhaps 100 different bacteria can be found on a housefly’s labellum, or eating apparatus, Dr. Marshall said. This pathogen list includes salmonella, E. coli, shigella, campylobacter and chlamydia. Things that make us sick.

Yet out of some 158,000 species of Diptera, just “a few dozen species of flies are causing an immense amount of difficulties,” he said. In fact, many families of flies are beneficial pollinators, akin to bees. But the bee must have a better publicist.

Ms. Lewis Levin ultimately discovered that her neighbors were not covering the garbage cans in front of the building. Flies were gathering there in the heat of the summer, then coming inside through openings in the bulkhead door. Soon after, Hurricane Irene blew through, she recalled. And the plague lifted.

WHEN a cloud of flies darkened the kitchen of Kristin Ohlson’s “big old wooden house” a dozen-odd years ago, she said, she thought she smelled a rat. Literally.

“There was this unmistakable odor of something dying or dead,” said Ms. Ohlson, a 60-year-old journalist and author.

A culverted stream runs beneath her neighborhood in Cleveland Heights, Ohio, acting as a kind of rat corridor. On the advice of a local hardware clerk, she had laid out poison over the winter. Ms. Ohlson hunted for the rat in every corner of the house before concluding it must have been entombed behind a wall.

The flies had no such trouble finding the body. “One day there were a handful of flies,” Ms. Ohlson said. “Then the next day there were 20 flies. And then the next day there were 200 flies.”

These were quite likely the black blowfly, Dr. Marshall said, a “dark, sort of metallic, gleaming indoor fly.”

Finally, Ms. Ohlson said, “I opened the window and took out the screens. My parents were visiting from California, and my dad said, ‘You’re letting the flies in.’ And I said, ‘No, I’m letting them out.’ ”

The cluster flies showed no such signs of wanting to leave Anne Yarbrough’s shingle-and-clapboard home on McNutt’s Island in Nova Scotia.

In 2007, Ms. Yarbrough and her husband, both retired United Methodist clergy, left Washington, D.C., for a kind of “pre-industrial life” in a 19th-century fisherman’s cottage.

After they moved in, she would lie in bed and imagine that the flies crawling through holes in the plank ceiling overhead were making their way to a “hidden fly kingdom.”

“We had a sort of war going on against them,” Ms. Yarbrough, 64, wrote in an e-mail, but “the fighting was all on our side.”

Ms. Yarbrough tried spraying with poisons, inflicting massive mortality. “But they always came back a few days later,” she recalled, “acting like nothing bad had ever happened between us.”

What would these flies be doing if they weren’t banging mindlessly against the windowpane? As larvae, cluster flies parasitize earthworms in moist dirt. In their adult stage, they congregate “near tree tops, on branches,” said Mr. Grimaldi of the American Museum of Natural History.

But for all their swarms, he maintained, the fly is not a social animal.

“I tried to be friends with them,” Ms. Yarbrough said. “But it’s really hard to appreciate flies.”

IN the annals of pest management, many of the Diptera go by an unscientific name: filth flies. The term carries more than a whiff of scorn. Still, a fly is a fly; it does what it does. Some would say we are the unsanitary ones.

Yet Emily Ho, 33, does not live in filth. “The thing with fruit flies,” she said, “is it seems it sometimes doesn’t matter how clean you keep the kitchen. And I keep a very clean kitchen. I keep food in jars or in the refrigerator. I clean the counter.”

Ms. Ho’s stylish one-bedroom apartment in the Silver Lake neighborhood of Los Angeles is a lab for her work as a food writer and consultant at MissChiffonade.com. Recently, she has been making small batches of natural soda, partly out of plants she forages from around the city.

An improvised funnel trap has thinned the flies’ ranks in Ms. Ho’s apartment. She places bait, like a ripe banana, in a tall glass or jar. Next, she rolls a piece of paper into a tight cone. Flies will enter the trap, she said, and “they don’t know how to fly out again.” (For all its genetics research, science has yet to definitively establish the I.Q. of the fruit fly.)

“Usually I’ll release them outside,” she said, “because I don’t want to kill them.”

Then an herbmonger at the farmers’ market suggested that Ms. Ho try guarding her fruit basket with a few sprigs of rue (Ruta graveolens) as a natural insect repellent. Voilà!

“The fruit flies totally disappeared, and I don’t know where they went,” Ms. Ho said. “It was pretty miraculous-seeming.”

They’ll be back.

A Devil With Wings

WHY do we hate the fly?

There’s the pestilence thing. The breeds-in-dung thing. The terrible table manners.

But does God hate flies, too? Steven Connor’s fascinating 2006 cultural history, “Fly,” marshals the evidence. “According to the Talmud,” he writes, “flies arouse disgust because of their habits of moving between filthy and clean circumstances.”

What about Lucifer’s wingman, Beelzebub, a k a the lord of the flies? In a court of law, this devil might have a winning case for mistaken identity.

He appears but once in the Old Testament, Mr. Connor writes, “as the name of the god of the Philistine city of Ekron.” This god, “Ba’al-zebub,” seemingly “offered protection against flies, or the maladies they conveyed.” A helpful fellow to have around.

Yet when this divinity returns in the New Testament, he has a slightly different name, Beelzeboul (perhaps “lord of the princes”), and he manages a portfolio of serious evil. This “seems to represent a considerable promotion for a minor local deity,” Mr. Connor writes.

Perhaps the real problem with flies, though, is their utter mindlessness. Observers as far back as Pliny the Elder, Mr. Connor writes, “thought no creature ‘less teachable or less intelligent.’ ”

And yet a pet fly is not an impossibility, said Dave Kapell of Minneapolis.

Mr. Kapell, 49, is an inventor and the creator of Magnetic Poetry. At age 12, sitting in his middle-school chemistry class, he was a fly trainer.

Here’s how you do it. “You catch a fly and then throw it really hard against the desk to stun it,” Mr. Kapell said. Next, ask a pretty classmate for a strand of long, fine hair. Tie a loop and cinch it around the fly’s body.

Finally, he said, “stick your leash down with some gum on your desk.” When the fly awakens, he said, it “will fly around on your little hair leash.”

Although this stunt sounds like an urban legend, Mr. Kapell vowed it is not.

Laura Bradford, the beautiful girl who donated her long black hair, could not be reached for comment.