The scent of a female

May 15, 2014 /

Pheromones make for a good story: a mysterious, invisible quality is what makes you “biologically” attractive (or not) to others — and you have no control over it. It’s an easy out for the romantically spurned — “I guess our pheromones just didn’t match” — and the reason dogs and babies seem to go barking mad in your presence. In LA there’s even this. But as zoologist Tristram Wyatt (as well as the mainstream scientific community) will tell you, there isn’t any hard evidence of pheromones in humans. Says Wyatt, there hasn’t been enough systematic analysis to know which molecules can be considered pheromones in humans — or even that they exist.

A pheromone is simply a chemical signal transmitted between individuals of the same species, often eliciting a social response. Regardless of the role they play with humans, pheromones are rampant in the animal kingdom, and are especially strong in insects. They use pheromones for all kinds of non-sexual activities, as is the case with ants as they communicate to each other what kind of tasks they’ve performed. As Wyatt says in his talk, “It works just as well underwater for goldfish and lobsters.”

The study of pheromones traces back to the 1880s: French scientist Jean-Henri Fabre observed that female silk moths were able to attract males across surprisingly far distances, which eventually led him to conclude it must be something about the odor emitted by the females. It wasn’t until 1959 that the first pheromone was really identified. German scientist Adolf Friedrich Johann Butenandt, also studying silk moths, worked ardently to isolate the molecule and make sure there were no other possible factors that could be affecting the males. This female sex pheromone in silk moths became known as bombykol. Science writer Joshua Howgego describes the way males find their mates: “Male silk moths can smell bombykol at concentrations of 3,000 molecules per cm2 of air, making them only slightly worse smellers than sniffing champions, dogs.” (Since silk moths have 10,000 times fewer nerves on their smell receptors than dogs, that’s pretty amazing.)

One particularly fascinating instance of pheromones among insects is the case of fruit flies. In 2007 a team from the University of Michigan discovered that male fruit flies, simply by smelling — that is, not coming in contact with — their female counterparts, showed a decreased lifespan. You read that right: Smelling the opposite sex actually shortened the lives of these male flies. As science writer and TED speaker Ed Yong put it, scientists found that “male flies store less fat, become easier to starve, age faster, and die quicker after detecting the scent of female.” Talk about femme fatale.

Meanwhile we humans can keep fumbling around in the dark with our paltry olfactory senses, falling in — or out — of love for whatever stupid reason we think matters.

[ted id=2002]


Photo: iStock.