A pheromone is a chemical produced by an animal, usually an insect, that influences the behavior or development of others of the same species, often functioning as an attractant of the opposite sex. "Love drug".
Here is a good description of what pheromones are and what effect they have on humans: http://www.fragrancex.com/customerservice/pheromones.html.
This chemical is also a trail left by the insects to indicate the other individuals of the source of food and with the help of these chemical products,other insects are able to reach the food source conveniently.We would have often witnessed the insects communicating head on with each other,and that is the way of exchanging chemical products.
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