Pheromones are natural chemical factors that are secreted, or excreted, and trigger social responses from members who are of the same species. These types of chemicals are capable of affecting the receiving individual by impacting their behavior once excreted or secreted from the body of the other individual. There are a number of pheromone types that have an effect on physiology or behavior; some of these types include sex pheromones, food trail pheromones and alarm pheromones. In addition to human use, the use of pheromones in insects has been documented particularly well.
Martin Lüscher and Peter Karlson were the two who first introduced the term in 1959. The term, pheromone, stems from “pherein”, a Greek word meaning to transport, and hormone, meaning to stimulate. Pheromones may also be referred to as ecto-hormones. Adolf Butenandt was a German biochemist who characterized and identified the first chemical, bombykol, which is a chemical released by female silkworms to attract their mates.
There are limits, however, that relate to the size of the organism and the effectiveness of the pheromones that are produced. For instance, bacteria are not able to make use of pheromones to attract the other sex, but they are able to use them to find similar organisms. Similarly, rotifers are simple animals that are too small in size for the females to lay a trail for a male to follow. On the other hand, copepods are slightly larger and are able to lay a trail of pheromones for males to follow.
Aggregation pheromones are used to overcome host resistance during a massive attack, for mate selection and to defend against predators. The term, aggregation, refers to a group of people (or individuals) who are at one locationnt. This group may consist of all females, all males or both males and females. Females produce most sex pheromones with only a small percentage of sex attractants being produced by males.
Alarm pheromones are released by some members of a certain species when they feel threatened or are attacked. These species release a substance that is considered volatile and that triggers a flight or aggressive response within the same species. For instance, aphids produce alarm pheromones that trigger the flight response while termites, bees and ants release alarm pheromones that trigger the aggression. When these types of pheromones are released by plants, the chemical that is released makes neighboring plants less appetizing.
Another type of pheromones are the signal pheromones, which result in short-term changes that activate responses. Territorial pheromones are released when an organism feels the need to mark their territory. For instances, in animals such as dogs and cats, these pheromones are present in their urine which is how they claim their territory. Ants, on the other hand, lay trail pheromones, which allow them to trail back to their beds with food. The trail is continuously refreshed as long as there is a continuous source of food. It evaporates quickly, which is why there is a need for constant refreshing.
When speaking in terms of sex pheromones, they indicate the female’s availability for breeding. The male counterpart of animals may also emit sex pheromones that provide information on their genotype and species. Many moths and butterflies are able to attract a mate with these sex hormones from a distance of up to 6.25 miles away.
When looking at pheromones in humans, there have been a few scientific studies that have been controlled and result in the indication of its existence. The most widely known study involves menstrual cycle synchronization among women. This study showed that women who were exposed to the smell of perspiration from other women had their cycles sped up or slowed down depending on when the sample was taken; the sweat was taken either before, during or after ovulation. Additionally, a newspaper report indicated that when women who were irregular in their menstrual cycles were exposed to extracts from male underarms, their cycles regulated accordingly.
The natural perfume of pheromones plays an important role in everyday life whether you are attracting another mate or are simply defending your territory. There are still questions in regards to whether or not pheromones actually exist in humans. Some advertisers claim to provide products that contain sexual pheromones in an effort to act as aphrodisiacs. Although this is their claim, there has been no substance within pheromones that has been shown in peer-review studies to influence this type of human behavior directly.