Pheromones direct ants to follow one of their number back to a food source, help male moths to search out a mate, cause bees to launch an attack, and are even used by spiders to attract unwary insects into their webs. Chemists coined the term pheromone to describe a wide variety of chemicals used by insects to communicate with others of their species to invite mating, warn of danger, and signal the location of a food source among a myriad of other functions. Of all the chemicals used by insects for communication, the sex pheromones have engendered the greatest interest, principally for population control.
Pheromone-baited traps are used to monitor and reduce populations of insects. One million traps deployed in Scandinavian forests over a four year period have greatly reduced damage from the spruce bark beetle. A Florida fruit fly’s numbers are controlled by placing the female’s sex pheromone into circular tubes containing powerful ultraviolet lights. As the male flies through looking for the female, it becomes sterilized and later matings with females result in no offspring. Pheromones are also sprayed on crops and forests to confuse male insects and hinder their finding the females. Pheromones are extremely potent attractants with only a few millionths of a gram being sufficient to lure the male. The non-flying female gypsy moth only emits a microscopic amount of sex pheromone for 30 minutes on a single night of her life yet that is all it takes for the male to home in on her and ensure the next generation.
Even as millions of dollars were invested into insect sex pheromone research, the possibility that similar compounds existed in humans was regarded as so much science fiction. Mammals such as mice and hamsters have sensory organs called vomeronasal organs (VNO) used to detect sex pheromones. Behavior elicited by the pheromones disappears if the organ is surgically removed. Does the VNO exist in humans? There is a great deal of controversy surrounding this question. The answer, according to science writer Robert Taylor in a recent issue of New Scientist, may force humans to change the way they regard their sexual behavior.
Anatomy texts of a century ago showed the VNOs as two small pits located about one-half inch up from the nostrils although their purpose was unknown. One anatomist said they existed in fetuses but disappeared by birth. By the turn of the century, they had virtually disappeared from text book illustrations of the nose. Three current anatomy texts surveyed by this writer could find no mention of them. But now David Berliner, a co-founder of Pherin Corpration in California, claims that not only do VNOs exist in humans but their role is to home in on the sex-pheromones given off by the opposite sex.
Berliner was studying the chemistry of the human skin when he found that certain extracts put his lab workers in extremely good moods. Luis Monti-Bloch, of the University of Utah, tested the extracts by a method long used for standard olfactory research. The body has smell-sensing organs called the olfactory epithelium that give an electrical response when exposed to odors such as clove oil. These gave no response when exposed to the skin extracts. Conversely, the area of the nasal passage that Berliner claims to be the VNO gave a strong electrical response to the skin extract while showing no response to odors such as clove oil. He says that not only do humans have VNOs but that much of what is called sexual attraction results from pheromones given off by the other sex. He bases this claim on the fact the the areas designated as VNOs in the male becomes electrically excited by skin extracts from the female and vice versa.
Although many researchers in the field remain highly sceptical of the existence of VNOs in humans, Berliner was sure enough of his facts to start a company called Erox that sells two perfumes and emphasizes the fact that they contain male and female sex pheromones. Ironically, the male perfume contains the female pheromone and vice versa because the idea is to make the wearer feel good and it is exposure to the pheromone of the opposite sex that seems to do the trick. He is also looking ahead to medications based on pheromones that would treat mood disorders such as acute anxiety by inducing a feeling of well-being.
If Berliner is right, it means nothing less than that he has rediscovered an organ that has been ignored by anatomists for decades. Moreover, as discover of humanity’s “sexual nose,” he will have had a hand in revising the way in which we look at our sexual behavior — as well as make a great deal of money!
Clair Wood is a science instructor at Eastern Maine Technical College and the NEWS science columnist.