Exploring The Chemistry Of Pheromones Biology Essay

The first pheromone was identified in 1953. This pheromone, called BOMBYKOL is secreted by female moths and carried a “ semen to me ” signal to males. This signal can go big distances and is effectual at low concentrations.

The mammalian pheromone system was more hard to understand because mammals, far from holding the simple stereotyped behaviour of insects, have complex and independent behavior. Mammals were found to observe pheromones through an organ in the olfactory organ called the VNO, which is similar in map to the olfactive membranes but connects to the hypothalamus.

Scientists were get downing to theorize whether a pheromone system existed in worlds. In the 70 ‘s Martha McClintock noticed that females populating in close propinquity underwent a changing of stage of their catamenial rhythms doing them to ovulate at similar times.

It was discovered that this consequence was due to a chemo signal, or pheromone. In 1974 Dr George Dodd discovered the first human sex pheromone, alpha-androstenol.

Although worlds are mammals, it is non certain that all pheromones are detected by the human VNO ; some may be detected by the olfactory membranes ( by normal smelling ) . It is known that pheromones do non necessitate to really be smelled to exercise their subconscious consequence, although human pheromones that are commercially available do hold a noticeable aroma at high concentrations.

However, non all people are really able to observe the witting smell of pheromones, but seemingly this does non cut down their subconscious consequence.

Although commercially available human pheromones address a quite specific country of human interaction, attractive force, pheromones play a function in other countries such as mother-infant bonding. Pheromone merchandises are besides from a specific household of pheromones which are derived from sex endocrines which indicate young person, birthrate, etc.

Everybody secretes these chemicals, but non in the same measures. Other pheromones are alone to the person, such as the pheromones that signal tissue type ( Major Histo-compatibility – the “ T-shirt survey ” ) .

The endocrine derived pheromones are of course secreted onto the tegument via the apocrine secretory organs, which are chiefly situated in the arm cavities and the pubic part ; the hair in these countries helps to scatter the pheromones efficaciously.

These scent secretory organs have in some instances evolved to execute an wholly different and specialized function, for illustration in the ear to bring forth ear wax, or in adult females ‘s chests to bring forth milk.

It is known that androstenol can bring on a spike in Luteinizing Hormone in both sexes, and this leads to a spike in testosterone degrees which may be responsible for feelings of attractive force.

Definition of Pheromones

A pheromone ( from Greek phero “ to bear ” + endocrine from Greek – “ drift ” ) is a secreted or excreted chemical factor that triggers a societal response in members of the same species.

Pheromones are chemicals capable of moving outside the organic structure of the releasing single to impact the behaviour of the having single. ( 5 )

Another definition of pheromones

Pheromones are of course happening substances the fertile organic structure excretes externally, conveying airborne messages that can bring forth societal responses from others of the same vitamin E species

Pheromones were foremost defined by life scientists in 1959 as chemical substances that can be excreted by the animate beings to trip the generative behavioral response from a receiver of the same species.

Pheromones are now widely recognized to be the go-between that promotes the endurance of each species. ( 6 )


1. Collection pheromones

2. Alarm pheromones

3. Epideictic pheromones

4. Releaser pheromones

5. Primer pheromones

6. Signal pheromones

7. Territorial pheromones

8. Trail pheromones

9. Information pheromones

Aggregation pheromones

Its maps in the defence against marauders, mate choice, and get the better ofing host opposition by mass onslaught. A group of persons at one location are referred as collection, whether dwelling of one sex or both sexes.

Male-produced sex attractant have been called collection pheromones, because they normally result in the reaching of both sexes at a naming site and addition in denseness of conspecifics environing of the pheromone beginning. ( 7 )

Most sex pheromones are produced by the females and little per centum of sex attractants are produced by males

2. Alarm pheromones

Some species that releases a volatile substance, when attacked by a marauder that can trip flight or aggression in emmets, insects are the members of the same species.

Pheromones besides exist in workss: certain workss emit dismay pheromones when grazed upon, ensuing in tannic acid production in the adjacent workss. These tannic acids make the workss less appetizing for the herbivores. ( 8 )

Alarm pheromones

3. Epideictic pheromones

Epideictic pheromones are slightly different from district pheromones, when it comes to insects.

Fabre observed and noted how “ females who lay their eggs in these fruits deposit these cryptic substances in the locality of their clasp to signal to other females of the same species they should seize elsewhere. ( 9 )


Signal pheromones that can do short term alterations ; such as, the neurotransmitter release which activates a response.For case, GnRH molecule maps as a neurotransmitter in rats to arouse hollow-back behaviour. ( 10 )

Signal pheromones between male parent and girl


Primer pheromones trigger a alteration of developmental events

6. TRAIL Pheromone

Trail pheromones are common in societal insects. For illustration, emmets mark their waies with these pheromones, which are volatile hydrocarbons.

Certain emmets lay down an initial trail of pheromones as they return to the nest with nutrient. This trail attracts other emmets and serves as a usher.

Trail pheromones

Equally long as the nutrient beginning remains, the pheromone trail will be continually renewed. The pheromone must be continually renewed because it evaporates rapidly. When the supply begins to dwindle, the trail devising ceases. In at least one species of emmet, trails that no longer lead to nutrient are besides marked with a repellant pheromone. ( 11 )


Laid down in the environment, territorial pheromones mark the boundaries of an being ‘s district.

In cats and Canis familiariss, these endocrines are present in the piss, which they deposit on landmarks functioning to tag the margin of the claimed district.

In societal sea birds, the preen described as ‘displacement activity ‘ . ( 13 )

8. Information PHEROMONES

Information pheromones are declarative of an animate being ‘s individuality or district. For illustration, Canis familiariss and cats deposit chemicals in and around their district, which so serve as an index for other members of the species about the presence of the resident in that district. ( 14 )


In animate beings, sex pheromones indicate the handiness of the female for engendering. Male animate beings may besides breathe pheromones that convey information about their species and genotype. ( 15 )

The sex pheromones


Some of the constructions of the pheromones are given below


2.2-methyl 4-heptanone

3.6-methyl 5-heptene- 2- 1

4.4 -hydroxy 4-methyl-2-pentanone


The general size of pheromone molecules can be limited to approximately 5 to 20 Cs and a molecular weight between 80 and 300. This is because below 5 Cs and a molecular weight of 80, really few sorts of molecules can be manufactured and stored by glandular tissue.

Above 5 Cs and a molecular weight of 80, the molecular diverseness additions quickly and so does the olfactive efficiency. Once we get above 20 Cs and a molecular weight of 300, the diverseness becomes so great and the molecules are so large that they no longer are advantageous.

Those pheromones are besides more expensive to do and transport and are less volatile. In general, the most sex pheromones are larger than other pheromones.

But it is the insects, they have a molecular weight between 200 and 300 and most alarm substances are between 100 and 200.

Pheromones, like the ocular communicating, usage individual, single messages every bit good as composite chemical messages.

For illustration, in many insects and mammals, each hormone secretory organ produces a pheromone with a different significance. However, many times pheromones from different secretory organs are secreted at that same clip.

Female WASP release attractant pheromones from their caput and sexual stimulant pheromones from their venters at the same clip. This can increase the effectivity of the message or make an wholly new message.

It is besides possible for different substances with different significances to be generated in the same secretory organ. ( 19 )

Dr. Winnifred culter -co-discoverers of human Pheromones ( 1986 )

Dr. Cutler ‘s research established cogent evidence that human pheromones affect relationships between work forces and adult females. Several old ages subsequently, in 1993, she took human pheromones one measure further. Dr. Cutler developed and marketed a man-made pheromone known as Athena Pheromone 10:13.

The pheromone is a transcript of one given off by “ sexually attractive ” adult females in their mid-twentiess and it is a colourless, odorless liquid adult females can have on to pull work forces. The pheromone proved to be successful and Dr. Cutler and the Athena Institute marketed more man-made pheromones, including Athena Pheromone 10X for work forces.

Development of Synthetic Pheromones

The development of other man-made pheromones, such as those used for plague control, is turning at an highly rapid rate. The chemical composings of insect pheromones are really good understood and scientists have been able to bring forth man-made pheromones with the same chemical construction.


Simple alterations to the constructions, such as adding a dual bond, junction, cyclic rings, or altering the places of the atoms can wholly alter the pheromone into a new pheromone. That is what leads to the E and Z pheromones and the differences between dienes and trienes, etc. Other pheromones include N in their construction, doing them amides. ( 20 )

Some of the pheromones illustration with the constructions ( 21 )

A Use of Synthetic Pheromones

One popular usage of man-made pheromones is for pest direction. Scientists use methods such as pest monitoring, mass caparison, enticement and putting to death, and copulating break to find valuable information about plagues, the dangers they pose to harvests, and how to work out the plague job.

Pest monitoring is used to find the intent for which a certain system of plague remotion is to be used. Some factors that are considered in these determinations include scientific factors and commercial factors.

Other of import constituents of supervising systems include the attractant beginning, the trap and where to put it, and sufficient cognition of the pest biological science to construe the gimmicks.

The attractant beginning is made up of the active ingredient and its controlled release device. The trap design is merely the basic construction of the trap itself and it includes designs such as gluey home bases, collapsible shelter traps, flying traps, funnel traps, and milk carton traps.

The three of import factors of trap arrangement are its tallness, place with regard to flora, and the trap denseness. Some applications of pest monitoring traps are listed in the tabular array below.

Figure from Insect Pheromones and Their Use in Pest Management, 1998, 264

Mass pin downing involves puting a high denseness of traps in the harvest to be protected to take a high proportion of persons from the population.

However, deficiency of attractive force of females to the attractant beginning, deficiency of efficient traps, high insect populations and trap impregnation, and a demand for high denseness traps per unit of surface country ( aka cost ) make mass caparison hard.

It is normally used on fruit flies, moths, and beetles.

Lure and kill techniques are really similar to mass caparison, except one time the insect is attracted to the semi chemical enticement, it is subjected to a violent death or sterilising agent alternatively of being trapped. It is besides known as attracticide and attraction-annihilation. Lure and putting to death consists of two constituents, the enticement and the affector. The enticement consists of smells, ocular cues, or both and the affector eliminates the insect from the population. Below is a tabular array of some common enticements and and affectors used. Lure and kill utilizations aim devices, including physical traps and sprayable preparations, which use pheromones that are released from planes and are easy released. It is chiefly used on fruit flies, house flies, and tsetse flies. )

figure from Insect Pheromones and Their Use in Pest Management, 1998, 301.

Copulating break is the usage of pheromones to seek and minimise or forestall egg laying by females. This is done by interfering with the copulating behavior procedures between males and females. Controlled release chemicals are used before the oncoming of plague activity and they are released in little sums for hebdomads or months. This scheme has become so successful that it is now used in agribusiness, gardening, and forestry.

The three major schemes of copulating break are confusion, trail-masking, and false-trail followers. Confusion is caused by the changeless exposure of males to a high concentration of pheromone fog, which causes version of the antennary receptors and addiction of the cardinal nervous system. This prevents the male from reacting to normal degrees of the pheromone released by females.

Trail-masking is utilizing a man-made pheromone to destruct the pheromone trail layed by the females. False-trail followers is puting legion musca volitanss of man-made pheromone in high concentrations to show the insect with many false trails to follow. It is dependent chiefly upon the figure and strength of the pheromone dispensers.

It took many old ages to develop environmentally safe controls that did non hold terrible effects on other species, but scientists have now achieved comparatively successful and specific chemicals. Copulating break is used for insect plagues of cotton, rice, forest insects, and fruit and vegetable plagues.


There are many advantages to utilizing chemical signals.

Some basic 1s include the fact that chemicals can convey through darkness, around obstructions, and they are really energetically efficient. Pheromones are comparatively inexpensive to biosynthesize and they can be released in a really simple mode, including the simple operation of opening a secretory organ.

Pheromones can besides last for yearss and be transmitted over great possible distances. This includes millimeters for micro-organisms and kilometers for other beings, without even changing the response or biogenesis. Some pheromones last so long that one time they are released, they are really used by the same being in the hereafter if it returns.

Some pheromones are non really specific and will consequence other species when they are released. For illustration, agitated honeybee workers discharge isoamyl ethanoate or 2-heptanone, which alarms the other nestmates but besides alarms any emmets or white ants that are in the locality. This is good to the emmets white ants, who are now cognizant of the danger that may be present. ( 22 )


There is one major disadvantage of chemical communicating.

It is really slow. Organisms can non rapidly convey pheromones over long distances or alteration from one chemical message to another. Besides, there has been no grounds that beings use amplitude and frequence transition in the transportation of pheromones.

Although slow transportation is a major disadvantage, beings have been able to accommodate to antagonize it. They do this by the generation of secretory organs and other chief biosynthetic sites to let the independent discharge of pheromones with different significances. One illustration of this is the black-tailed cervid.

The cervid produces pheromones in at least seven different sites, including piss, fecal matters tarsal secretory organs, metatarsal secretory organs, preorbital secretory organs, forehead secretory organs, and interdigital secretory organs. The pheromones from each site have a different map.

Comparison of Synthetic and Natural Pheromones ( 23 )

Many times, man-made pheromones that are used in plague control, insect monitoring, etc. are successful, as mentioned in the “ usage of man-made pheromones ” subdivision. Scientists can really flim-flam insects into believing the man-made pheromones are really natural pheromones released by other insects.

Therefore, there is non much argument about whether or non man-made pheromones used for insect control are effectual and similar to natural insect pheromones.

The controversial comparing is between human pheromones and the man-made human pheromones, now being produced and added to Colognes, aromas, etc.

The pheromones that are located in the aromas are really androstenone and androstenal, or known to critics as “ hog pheromones ” .

Figure taken from hypertext transfer protocol: //www.erox.com/SixthSense/StoryOne.html



The Washington Post, 11/18/86.

Pheromones Discovered in Humans ( 24 ) Newspaper.

by Boyce Rensberger

‘Scientists in Philadelphia have established for the first clip that the human organic structure produces pheromones, particular aromatic chemical compounds discharged by one person that affect the sexual physiology of another.

Although animate beings have long been known to release pheromones, which typically function as sex attractants, and although the being of such chemicals in worlds has long been speculated, the new research is the first to set up their being in worlds ‘

USA Today, 11/19/86

The Real Chemical Reaction between the Sexes ( 25 )

United statess Today

by Kim Painter

Chemicals in work forces ‘s organic structures can do their female sex spouses to be more fertile, have more regular catamenial rhythms and milder climacteric, landmark research shows.

And adult females who have sex with work forces at least one time a hebdomad benefit most from the chemicals, which seemingly work through the sense of odor.

“ The exciting portion is the consequence we have on each other. Work forces are of import to adult females, ” says Dr. Winnifred B. Cutler of Philadelphia, whose surveies show for the first clip that chemicals called pheromones exist in worlds.

Pheromones have long been known to be in animate beings, as aromas that attract sex spouses. Cutler ‘s new surveies… show adult females are affected by pheromones from work forces and adult females:

*Women exposed to another adult female ‘s “ female kernel ” menstruated at the same clip after a few months, corroborating a long-observed phenomenon that adult females who live together menstruate at the same clip.

Cutler ‘s other surveies show adult females who have sex with work forces at least one time a hebdomad have regular catamenial rhythms and fewer birthrate and climacteric jobs, seemingly because of exposure to pheromones.

CNN Online, and WebMD.com article, 6/25/99

Pheromones: Potential participants in your sex life ( 26 )

By Deb Levine

Copyright WebMD.com

In 1986 Dr. Winifred Cutler, a life scientist and behavioral endocrinologist, carbon monoxide discovered pheromones in our underarms.

She and her squad of research workers found that one time any overbearing underhand perspiration was removed, what remained were the odorless stuffs incorporating the pheromones.

Dr. Cutler ‘s original surveies in the ’70s showed that adult females who have regular sex with work forces have more regular catamenial rhythms than adult females who have sporadic sex.

Regular sex delayed the diminution of estrogens and made adult females more fertile. This led the research squad to look for what the adult male was supplying in the equation.


As you can see, pheromones are a much bigger portion of our lives than signifier of chemical communicating between beings.

There have been important additions in the cognition worlds have about pheromones in the past several decennaries, but there is still plenty of information we do non cognize about them.

For illustration, we might cognize the chemical construction of human pheromones, but we have yet to find whether or non the VNO plays a function in their map or if the VNO is even functional.

The survey of insect pheromones has set the foundation for the survey of pheromones as a whole and in recent old ages we have been taking it a measure farther, to the human pheromone degree.

As ever, engineering has allowed us to make more and more experiments and get more and more cognition about pheromones.

Some of the consequences of recent surveies are amazing ; merely take a expression at the article by Dr. Gallup that will be released in June 2002. If the rapid additions in experimentation and cognition continue, shortly we might be able to command other people ‘s actions, merely like we control insects, by merely spraying a chemical. ( 27 )