What are pheromones? Pheromones, as defined by John W. Kimball, are chemicals released by an organism into its environment enabling it to communicate with other members of its own species. The term Pheromones (originates from two Greek words, pherein meaning transfer and hormone meaning to excite or stimulate), as proposed by Karlson and Luscher(1959) was used to describe a chemical secreted by an animal to release a specific reaction that triggers members of its own species. Pheromones are subclass of semiochemicals, a broader term for chemicals involved in animal communication within same species. And the action of pheromones between individuals is contrasted with the function of hormones as internal signals within an individual organism.
1.1 TYPES OF PHEROMONES
Pheromones are specific chemical signals produced by an organism to signal its presence to other member of its own species. Different organisms secrets different types of pheromones which helps them to identify each other for specific purposes ranging from insects to mammals. Pheromones in mammals is divided into Releaser pheromone and Primera pheromone , as proposed by Wilson and Bossert in 1963. The releaser is the pheromone which induce and mediate behavioural changes, and the primera is the pheromone which initiates changes in development such as sexual maturation. Furthermore, the insect pheromones are divided into; sex pheromone, aggregation pheromone, alarm and trail pheromones.
Table 1. shows the different types of pheromones. TYPES OF PHEROMONES | FUNCTION | Insects Pheromones | | 1.Alarm pheromones | It signals alert when there is intrusion from predator | 2.Trail Pheromones | It attracts and guides other ants to the food | 3.Sex Pheromones | It is release by the female to attract the male for mating | 4.Aggregation Pheromones | It signals the formation of animal group of same species, it attracts conspecifics of both sexes | | |
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