By Natalie Johnson, Jayplay writer "I reached in the locker - grabbed the Spanish fly/ I put it with the monkey - mixed it in the cup/ Went over to the girl 'Yo baby, what's up'" Any Beastie Boys fan would know those lines. What's less-known is the definition of Spanish fly, an ancient aphrodiasiac, the mechanics of which are decidedly un-sexy. According to www. spanish-fly.edog.org, the fly is actually a beetle that secretes a chemical called cantharadin when frightened. When ingested and passed through by humans, cantharadin causes genital itching and swelling — mistaken by Europeans 500 years ago to be arousal. The myths and science behind aphrodisiac edibles often clash: foods are considered aphrodisiac only because of shape or tradition, not because of any proven biochemical effect. Cynthia Akagi, associate professor of health and education, says that the only proven aphrodisiac is yohimbine, an extract from the bark of an African tree. However, any food used during sexual interaction could "add to the experience," she says. Lists of aphrodisiacs can be found anywhere from cookbooks to health Web sites. Here's the story behind five of the most common ones. Avocados The avocado got the "aphrodisiac" distinction based on looks. The fruit grows in pairs on trees, and according to an article in the London Times, was called "ahuacuatl" by the Aztecs — "testicle tree." The androgynous food also imitates a woman's softness and curves and genitals. (Slice one in half, remove the pit, and take a look.) Chocolate In addition to sexy looks, most aphrodisiacs have health benefits. In her book Nature's Aphrodisiacs, author Nancy Nickell writes that most aphrodisiacs provide nutrients that keep the reproductive system functioning. The avocado's one of them: It's a good source of potassium vitamins C and E, and riboflavin, according to www.avocado.org. Chocolate's got a lot of stre cred. A mainstay of Valentine's Day and repentant boyfriends everywhere, it has been used as a food for lovers since its development by the Aztecs and Maya thousands of years ago. These ancient civilizations reserved chocolate drinks for priests and kings, according to The True History of Chocolate, by late anthropologist Sophie Coe.The book traces the scientific name for the cocoa tree, theobrama cacao, to the Greek "food of the gods." In early 2005, researchers at the San Raffaele Hospital in Milwaukee Hospital in Milan found that a stronger sex drive than those who don't. women who eat chocolate daily have Oysters Oysters are slippery, exotic and hard to open — an excellent sex metaphor in a tightly clamped shell. Ancient Romans sent slaves to the English shores to gather them, according to an article in the Detroit Free Press, and would also pay for them by their weight in gold. Oysters are considered representative of female genitalia. They also contain a lot of zinc. Sexual expert and therapist Ava Cadell says that zinc releases testosterone, the most powerful sex hormone. She says testosterone, when released in men and women, makes them more aggressive sexually. Raspberries and Strawberries Fruit and flowers have always symbolized sex. Stare at a Georgia O'Keefe long enough and you'll start to blush, and slang is full of fruit's influence — what do you think of when you hear "melons?" Raspberries and strawberries are two classic aphrodisiacs. They're accessible, nutritious, and erotic — the deep purple and bright red are stimulating on their own. According to a study published in the Journal of Medicinal Food, 6. these berries inhibit the growth of 12 different bacteria and a strain of yeast. A Creighton Medical School study in 2004 found that the berries are rich in anthocyanin, a powerful antioxidant. The chocolate-covered strawberry, that double-whammy companion of champagne and romance, is a great way to maximize the berry's aphrodisiac abilities. Bananas No aphrodisiac list is complete without a phallic symbol. Like cucumbers, carrots, asparagus and zucchini, a banana is terrific phallic symbol, an aphrodisiac that's anything but subtle. Dr. Cadell says that bananas have significant enzymes and nutrients that create arousal. She says bananas specifically have bufotenine, an enzyme that's linked to increased confidence, happiness and libido. Easy to get and fairly cheap, the potassium-rich fruit is a visual and nutritional aphrodisiac. Aphrodisiacs have been a part of countless cultures, and a subject for hundreds of studies. To study aphrodisiacs is to study history, biology, psychology and romance. Although avocados, bananas, berries, chocolate and oysters haven't been proven to make sex better, they are good for you. And they're just a tiny fraction of the aphrodisiacs out there: as family practice physician Cynthia Mervis says in her book Love Potions: A Guide to Aphrodisiacs and Sexual Pleasures, anything can be an aphrodisiac, from candles to lingerie to marijuana — it's all in what you make of it. ---