Report on Pheromones

Part 2

1.) The direct answers: the behavioural answer to the olfactory perception of the pheromones is illustrated by the example of some males mammals, for which the sight of the female genitals provokes sexual excitement. This physical answer is ordered by the central nervous system. In the same way, fleeing is the behavioural answer to the alarm pheromone for antelopes. This behaviour is ordered by the central nervous system when the pheromones have been perceived by the olfactory neurons. Another example is the particular position that a swine female adopts automatically in order to facilitate penetration when she smells the pheromone 3alfa androstenone from the saliva of the male over her. Actually there are the pheromones present in our saliva that can make us lose our mind with a kiss.

2.) The indirect answer is a very insidious and powerful one because it consists in activating the endocrine system of the recipient through the olfactory stimulus. The olfaction is a part of the primitive “reptilian” brain that sneaks out from a hole of the skull in search of chemical information. It is not composed of nerves that pick up and transmit the stimuli like for other perception organs but of constantly renewed neurons. The primitive brain, that is, the limbic system, is the centre of unconscious physical functions (respiration, heartbeat, etc) and controls not only all biological functions of the body through the hormone production (renins for the arterial pressure etc), but also all emotions be they most primitive (fear, hunger, sexual desire) or most evolved (love, feelings, ecstasy). This capability (or power) to provoke an effect on the inner biological regulation of another individual used by all species in the reproduction process in order to increase their possibility of survival. The example of the red fish Carassius Auratus shows how pheromones coordinate such process. In the evening while the female matures the eggs, its high level of steroids overflows in the water and the pheromone is perceived by the olfaction of the male. Its brain is then stimulated to produce hormones that start the sperm production. In the morning, during the ovulation, the eggs in the reproductive track initiate in the female the production prostaglandin that determinate her own sexual behaviour. Metabolics of prostaglandin overflows in the water and stimulate the sexual behaviour of the male.

It is now understood that in the animal kingdom, more interactions are carried out by pheromones than by any other type of signal. The evolution of these signals on very short period of time is very probable because of the particular design of the olfaction (activation of the endocrine system and existence of the olfactory memories) and because odour cues are tremendously important in increasing reproductive and survival success.

I personally assert that olfactory memories are so important in the learning process for survival that it is highly probable that they be genetically transmitted from one generation to the other. In this way all odours whose recognition may increase reproduction success or survival are immediately integrated in the behaviour of organisms.

There is in reality much less difference between pheromones from invertebrates and vertebrates than could be thought. Also the behaviours that they provoke in various species are very similar.

The power of smells and particularly of pheromones to provoke primordial emotions and to provoke social behaviours is a power coveted by the adepts of marketing and communication. They would happily compel consumers to buy a product without their being aware of that. We point out that no laws regulate the use of these molecules in marketing and advertisement. It has been observed that synthetic pheromones used in perfumery fragrances (synthetic musks) not only are toxic (see greenpeace report) but can also provoke confusion about one’s own sexual identity.