What is a pheromone and is it a well-defined, scientifically useful concept?
The term pheromone was coined to describe a chemical substance which carries a message about the physiological or behavioral state of an insect to members of its own species, resulting in ‘a specific reaction, for example a definite behaviour or a developmental process’ (Karlson and Luscher, 1959). It is clear in the original description, and in a later more extensive review of examples (Karlson and Butenandt, 1959), that this was to be real communication, beneficial to the sender and, by implication, to the receiver. Karlson and Luscher state: ‘the organism . . . creates for itself a means of communication . . .’ (Karlson and Luscher, 1959). We can be sure that the authors did not mean that the individual organism created this capacity, but that it was established and maintained by natural selection.
