Key Terms in Evolutionary Biology of Sex, Gender, and Sexuality: Pheromones

= Pheromones =

Definition
Pheromone (n): A chemical substance that is usually produced by an animal and serves especially as a stimulus to other individuals of the same species for one or more behavioral responses.

Definiation found at www.merriam-webster.com

Example(s) of use in context
In the context of our class pheromones being produced and used by humans is debatable. We did not discuss pheromones directly, however they were mentioned in a movie we watched by PBS about the biological workings of different sexes. In the movie an experiment was done with female identical twins in a night club. One had no scent on and the other wore a specific scent, thought to attract men. The one with no scent was only approached by a couple men, the one with the scent on was approached by a considerably higher number of men in the club.

Scientific background &amp; history
The concept of pheromones was first introduced by Peter Karlson and Martin Lusher in 1959. Karlson and Lusher were studying invisable forms of communication among invertibrates. According to them pheromones were "substances which are secreted to the outside by an individual and received by a second individual of the same species, in which they release a speciﬁc reaction, for example, a deﬁnite behavior or a developmental process" ( Charles J. Wysocki and George Pereti,  Facts, Fallacies, Fears , and Frustrations With Human Pheromones, pp1201 , The Anatomical Recond Part A, 2004). Karlson and Lusher also indentified the first chemically definable pheromone, bombykol, which is released by female silk moths in order to attract a male mate. Since this first discovery of bombykol in silk moths quite a few other pheromones have been found and isolated in different animals.

A good example of animals who have been found to produce and use pheromones are pigs. Male pigs secrete androstenone which are recieved by sows in heat. Androtenone works so well on female pigs that farmers can buy the pheromone from retailers in order to assist in the reproductivity of their pigs ( Charles J. Wysocki and George Pereti,   Facts, Fallacies, Fears , and Frustrations With Human Pheromones, pp1202, The Anatomical Recond Part A 2004).

Since the concept of pheromones has been introduced there are four different categories into which different types of pheromones are organized. These categories are;

1.releaser pheromones (RP)

2.primer pheromones (PP)

3. signaler pheromones (SP)

4. modulator pheromones (MP)

RPs are believed to envoke a specific response from the animal receiving them. PPs are thought to need a little more time to settle in the reciever than releaser pheromones are, and are believed to affect systems in the body related to development or reproductive physiology. SPs are thought to provide the recipent with specific information about the individual animal from which they come and MPs have been said to possibly affect the mood of the recipiant.

Despite the evidence that certain animals produce and recieve hormones from others in their species, there is no concrete evidence that humans produce or recieve any. This is because researchers have yet to isolate a specific pheromone in secretions (most often sweat) from the human body. Becuase of this lack of a chemically legitimate pheromone being found in humans the debate as to whether it exsists or not is still up in the air. There is no solid evidence that proves humans produce and are affected by pheromones, however there is no solid evidence agains the idea either ( Charles J. Wysocki and George Pereti,   Facts, Fallacies, Fears , and Frustrations With Human Pheromones The Anatomical Recond Part A, 2004).

Debates &amp; controversial applications
The current debate among researchers is whether or not humans can produce and recieve pheromones. Many claim that there is no way human produce and act under the influence of pheromones because we have yet to actually find and isolate a true pheromone in human secretion. However a number of researchers also claim that it is entirely possible for humans to produce and react to pheromones, and that their is enough evidence to support the possiblity of the claim. Further, just because a pheromone has yet to be isolated does not mean it does not exsist. Another problem within in this relam, which makes finding proof of human pheromones even harder is that it is entirely possible that a pheromone is made up of multiple compounds, which means not onl do individual compounds need to be examined, but so various combinations of compounds. There is also the likelihood that humans do not secrete pheromones at all and the scents that attracts us to other individuals are not attractive because of the exsistance of a phermone but because of a "signature oder" made up of genetics, bacteria in our bodies, and the types of food we eat. Because there is so much research to be done on human sweat and the different compounds within in it it is hard to say how long it will be before we truly know if humans produce and are affected by pheromones or not.

Another reason some researchers believe that humans cannot be affected by pheromones, even if they did ever produce them, is that the vomeronasal organ (VNO) is no longer functional in adult humans. The VNO is still functional in animals, which is why they are affected by the pheromones they produce ( Charles J. Wysocki and George Pereti;   Facts, Fallacies, Fears , and Frustrations With Human Pheromones,  pp1201, The Anatomical Recond Part A, 2004). There has been some research claiming the production and use of primer, signaler, and modulator pheromones within humans. The most populat debate about humans and pheromones involved the primer pheromone and its posisble affect on the syncing of menstrual cycles of women who live close together (think roomates). One study (Schank, Jeffery C. Do Human Menstrual-Cycle Pheramones Exsist? Human Nature, Volume 17, 2006) looked at multiple studies done in the 1970's and 1980's on this very subject. The researcher hoped to find legitmate errors within each study, disproving the theory that women, when living in close quarters, respond to different pheromones giving off by one woman on her menstrual cycle and innevitably, becuase of the pheromone, sync up. The conclusion drawn from this study was that there where some serious errors in the calculation of the supposed syncing. It seems more likely that women will innevitably overlap a day or two during their periods, but this is simply chance, due to the idea that each cycle functions under it's own, ever-chaning, rhythems and patterns.

Overall there is strong evidence for both sides of the argument, however until a human pheromone is isolated one cannot claim that it is a fact that human pheromones exsist, nor can they claim that is a fact that human pheromones do not exsiste.

Images


Bombykol, the first chemically legitmate pheromone found, is produced by female silk moths to attract male mates



Brown algae pheromones

Author
Kimmy Tronolone