[Annual Fly Control Issue] Fruit Flies and Love

What’s the quickest way to a man’s heart? No, not through the chest wall with a knife.

According to Mom wisdom, it’s a cozy meal, in a penumbra of pleasure that mingles the fragrant food with the cook. If men are anything like common fruit flies — and who’s to say they’re not at times; heaven knows women are — Mom was right.

Anyway, that’s the romantic ploy of female fruit flies, for whom a dinner date is the ultimate rush. And rush it literally is, since they live only about 25 days and can’t afford to be shy. Still, the males need to be in the right mood, and the females are surprisingly picky and manipulative, given their short careers. Did I mention that some fruit flies have come-hither eyes? I don’t mean the dozens of mosaic facets, so evocative of hippie sunglasses, but the zingy psychedelic eye colors lab folk like to breed into them, the better to study mutant genes. As a Cornell grad student, I often stopped by the fetid biology lab to admire the eggplant-blackness of the abdomens, the spiky hairs, the gaudy prisms of the eyes — some apricot, some teal, some purple, some the brick-red of Ming vases.

A favorite of biologists, fruit flies have it all — they’re prowling for mates within 12 hours of birth, they’re easy to raise and they can lay 100 eggs a day. Plus, they share most of our genes, including about 70 percent of those we’ve linked to such diseases as Parkinson’s and Alzheimer’s.

Because fruit flies thrive in sultry 80-degree weather, the lab in my graduate student days offered a warm den during those numbing upstate winters when ice clotted in beards and mittens, co-eds exhaled stark white clouds and the walkways looked like a toboggan run. I don’t recall what experiments were unfolding, only the tiny haunting eyes of the fruit flies, like the captive souls of past lab assistants, and the swooping melody of their Latin name: Drosophila melanogaster, which translates poetically as “dark-bellied dew sipper.”

During fruit fly courtship, the male, lured by a full larder, extends one mandolin-like wing and serenades the female, then engages in a style of oral sexual foreplay many humans enjoy. Then he mounts her and copulates for 20 minutes or so. Here’s the sly part. The last male she has sex with will sire most of her many offspring and she chooses the father only after lots of romps in the orchard or lab, based on his flair for courtship.

As with most animals, from squirrels to spiders, the males pursue but the females choose, and even the lowly fruit fly can be choosy.

Why the dinner date? Because Live Fast and Die is their mantra, and they need a handy food supply if their large new brood is to survive.

I first noticed a similar meal plan among the annual hordes of Japanese beetles that tat rose leaves into doilies. Gardeners often spy the iridescent scarabs perched atop favorite flowers, dining and mating simultaneously. “I don’t mind if you have sex on the roses,” I tell them peevishly. “Really. Knock yourselves out…I just wish you wouldn’t eat at the same time!”

Of course, the ancient Greeks and Romans, who coined the word “orgy,” and found that dining lying down leveled the playing field, enjoyed blending sensory delights with equal gusto — banquets of music, food, dancing, alcohol and sex. Why would fruit flies be any different?

We may respond to the same honeyed aromas that make fruit flies amorous, so chemists include them in perfumes. Many a medieval troubadour used a mandolin to serenade his lady, with whom he’d dine and mate. And remember that sexy tavern scene in “Tom Jones,” in which the hero and buxom wench devour a carcass with carnal abandon?

So, is the human dinner date really just courtship feeding after all, a custom we share with fruit flies, robins and chimpanzees? Yes. But what’s the harm in that? As Cole Porter once put it: “Birds do it, bees do it, even educated fleas do it…”

 

Diane Ackerman is the author of “The Zookeeper’s Wife,” and a contributing opinion writer for The New York Times.

Illustration by Britt Spencer
 

From The New York Times, Jan. 15, 2012,
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