Advantages and Disadvantages of Pheromones
There are many advantages to using chemical signals. Some basic ones include the fact that chemicals can transmit through darkness, around obstacles, and they are very energetically efficient. Pheromones are relatively cheap to biosynthesize and they can be released in a very simple manner, including the simple operation of opening a gland. Pheromones can also last for days and be transmitted over great potential distances. This includes millimeters for microorganisms and kilometers for other organisms, without even altering the reception or biosynthesis. Some pheromones last so long that once they are released, they are actually used by the same organism in the future if it returns. (Sociobiology: The Abridged Edition, 1980, 114)
Some pheromones are not very specific and will effect other species when they are released. For example, agitated honeybee workers discharge isoamyl acetate or 2-heptanone, which alarms the other nestmates but also alarms any ants or termites that are in the vicinity. This is beneficial to the ants and termites, who are now aware of the danger that may be present. (Sociobiology: The Abridged Edition, 1980, 94)
There is one major disadvantage of chemical communication. It is very slow. Organisms cannot quickly transmit pheromones over long distances or change from one chemical message to another. Also, there has been no evidence that organisms use amplitude and frequency modulation in the transfer of pheromones.(Sociobiology: The Abridged Edition, 1980, 114)
Although slow transfer is a major disadvantage, organisms have been able to adapt to counteract it. They do this by the multiplication of glands and other principal biosynthetic sites to allow the independent discharge of pheromones with different meanings. One example of this is the black-tailed deer. The deer produces pheromones in at least seven different sites, including urine, feces tarsal glands, metatarsal glands, preorbital glands, forehead glands, and interdigital glands. The pheromones from each site have a different function. (Sociobiology: The Abridged Edition, 1980, 114)
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