Stacey May, M.A., is the director of public outreach at AAPS.
Pheromones, chemicals secreted or excreted by the body that trigger a behavioral or physiological response in members of the same species, come in all shapes and sizes. They can facilitate communication, warn you that a predator is approaching, stave off others from laying their eggs near yours, stake out your territory (those of you with male dogs are all too familiar with this one), or lead you to a viable food source. Found in creatures from insects to complex vertebrates and even plants, pheromones highlight some of the wonderful ways in which our biology and chemistry can work together to help keep us safe. But as Valentine’s Day quickly approaches, we’d rather focus our attention on another type of chemistry: sex pheromones …
So what, exactly, are sex pheromones, and how do they work? In animals, sex pheromones can announce that a female is ready to breed, and that a male is of the correct species to copulate with. Even bacteria, including strep, send signals that allow transformation, or the taking up of DNA from other cells and incorporation into their own genome. Numerous studies in yeast, fungi and mold tell a similar story, as do studies in moths, sows and even sea urchins and silkworms. In fact, moths and butterflies can detect a “willing” male up to 10 KM (6.2 miles) away!
Let’s talk about humans for a bit. Pheromones are detected primarily by the vomeronasal organ (VNO) located at the base of the nasal septum. The VNO, also present in reptiles, amphibians and non-primate mammals, contains three distinct families of G protein-coupled receptors (ViRs, V2Rs, V3Rs) to detect the presence of pheromones.
I know what you’re thinking. “I’m a reasonably intelligent human being who can make my own decisions… I’m sure pheromones don’t affect me.” Well, I hate to tell you, but on some level, you’re wrong. While humans are highly dependent upon visual cues, smells can also play a distinct role when in close proximity. Studies in humans, including those on the VNO and axillary steroids, have concluded that these sex pheromones can also affect the perception of pain in women, menstrual cycles, ovulation, and sociosexual behavior.