What the Nose Knows - Avery Gilbert [19]
—WALT WHITMAN, Leaves of Grass
Pine forest or prairie, seashore or bayou, the essence of the ambience is there for the taking. To carry it away, all you need is a pump and a trap. To reproduce it is not trivial—it’s a matter of money and determination—but it is firmly within our technological grasp. We can re-create the scent of coyote mint and pennyroyal and Sierra Mountain Misery. We can project them into your living room or office cubicle. Imagine them unspooling in slow transitions—a diorama for the nostrils—while you listen to Muir’s afternoon on the Feather River, or to Whitman’s ode to the American outdoors. What would you like to smell? For myself, I’d vote for the sea breeze at Point Reyes and the scent of the redwoods at Big Sur.
IN HIS 1947 MEMOIR Speak, Memory, the novelist and butterfly expert Vladimir Nabokov recounts a moment from one of his summertime collecting trips:
Unmindful of the mosquitoes that coated my forearms and neck, I stooped with a grunt of delight to snuff out the life of some silver-studded lepidopteran throbbing in the folds of my net. Through the smells of the bog, I caught the subtle perfume of butterfly wings on my fingers, a perfume which varies with the species—vanilla, or lemon, or musk, or a musty, sweetish odor difficult to define.
Scented butterflies are not exotic or rare. The Green-veined White, for example, is common throughout Europe and in parts of the United States, where we call it the Mustard White. To the British lepidopterist George Longstaff, its “strong and distinct” odor resembled lemon verbena. Back in 1912, he wrote: “It is curious that to this day so few persons are practically acquainted with the scent of the Green-veined White. When, at the Brussels Conference, in 1910, I caught a male G. napi in the beautiful garden of the Congo Museum, and demonstrated the scent to half a dozen entomologists present, none of these gentlemen had perceived the scent before, though at least one of them was a very eminent observer.” The situation hasn’t changed much in the last hundred years. No current field guides mention the scent of the Green-veined White—or of any species, for that matter. The fussy “butterflies through binoculars” crowd discourages physical contact with actual insects, but there are plenty of Mustard Whites in the Rocky Mountains, and you don’t have to be as brutal as Nabokov. Go ahead and catch one for yourself. Sniff and release.
In Longstaff’s field notes, one finds an astonishing range of butterfly odors. Some are like confections (vanilla, chocolate, burnt sugar), others like flowers (freesia, jasmine, heliotrope, mango flower, honeysuckle, sweetbriar). Yet others are like herbs and spices (cinnamon, lemon verbena, orris root, sandalwood, musk). Longstaff also found a spectrum of unpleasant scents, some reminiscent of cockroach or muskrat, others of rancid butter, butyric acid, vinegar, acetylene, musty straw, cow dung, horse stable, horse urine, and ammonia.
We now know that the lemony body odor of the Green-veined White contains alpha-pinene, beta-pinene, myrcene, limonene, linalool, p-cymene, neral, and citral. (The first five ingredients are also found in cannabis oil. Why should a psychoactive hemp plant and a butterfly share odors? Nature is wonderfully strange.) Males of the Green-veined White have another scent, which they hold in reserve for special occasions. It is methyl salicylate, easily recognized as the odor of wintergreen (or Pepto-Bismol). The male uses it as an antiaphrodisiac: he transfers the scent into the female at mating and it discourages other males from copulating with her afterward. Related species have their own versions of this turn-off tactic: the Small White uses a blend of methyl salicylate and indole; the Large White uses benzyl cyanide. These chemical countermeasures can backfire, as when the Large White’s antiaphrodisiac aroma draws unwelcome attention of a tiny parasitic wasp called Trichogramma brassicae. When a female wasp smells