Welcome

Pheromones chemical signals between animals of the same species. Pheromones have been found in species from almost every part of the animal kingdom, on land, in air and water Wyatt 2014, 2009). Invertebrates and vertebrates are similar to each other in the ways they use chemical communication; the parallels in uses and sensory processes are numerous, even if we are not always sure if this is by convergence or shared ancestor.

However, there is still a debate about what pheromones are and are not in chemical communication, particularly in mammals. I think the problem continues to be the distinction between a pheromone, a molecule(s) produced by all male mice, for example, and what I propose we call a signature mixture, an individual male’s distinctive mix of molecules, which a female mouse learns and uses to recognize him as a particular individual. The colony odors of social insects are also signature mixtures, learned by nestmates. Pheromones occur in a background of molecules which make up an animal’s chemical profile consisting of all the molecules extractable from an individual.

Signature mixtures are the subsets of variable molecules from the chemical profile that are learnt by other members of their species and used to recognize an organism as an individual or as a member of a particular social group such as a mongoose family group or ant colony (Wyatt 2010). ‘Signature’ is used as it implies individuality. A key difference between pheromones and signature mixtures is that in all taxa so far investigated it seems that signature mixtures need to be learnt (Wyatt 2014).

Among the surprises in recent years was the discovery that the Asian elephant Elephas maximus, shares its female sex pheromone, (Z)-7-dodecen-1-yl acetate, with some 140 species of moth. Whether humans have pheromones is discussed in Chapter 13 of Wyatt (2014).

[For more discussion of these ideas see Wyatt (2014)]