Allelochemical communication in vertebrates: kairomones, allomones and synomones

Communication between different species by means of chemicals (allelomones) is widespread among prokaryotes, plants and invertebrates. This study reviews data suggesting that allelochemically mediated communication also exists among vertebrates. The work aims to provide a concise, interdisciplinary review of communication mediated by infochemicals, with a focus on interspecies and interkingdom signaling. A definition of infochemicals is given, with a brief review of the general principles of chemical communication in different kingdoms in nature. Findings are reported which suggest that interspecies chemical signaling is important for vertebrates also. It is proposed that the general laws of chemical ecology are valid for mammals too, and that the terms indicating the different types of allelomones (i.e. kairomone, allomone and synomone) might also be used in medicine. In particular, the microchemical environment at the airway and digestive interfaces are discussed from an infochemical point of view.