ABSTRACT
Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal 2, 28006 Madrid, Spain.
* Corresponding author
Pheromones have been defined, based on entomological studies, as chemicals or semiochemicals produced by one individual that effect a change in the physiology (‘primer’ pheromone) or behavior (‘releaser’ pheromone) of conspecifi cs (Karlson and Lüscher 1959). In insects and many other invertebrates, very often just one or a pair of chemical compounds acts as an exclusive pheromone attracting the opposite sex. In contrast, vertebrates often have multicomponent pheromones with a mixture of many different chemical compounds with distinctly different functions or intended receivers (Müller-Schwarze 2006). However, compounds may be mixed together in specifi c proportions to determine “odor profi les” of species or individuals (Johnston 2005; Wyatt 2010). The pattern of compounds in the scent of an individual may convey various signals such as sex, age, social status, group, individuality, seasonality, condition, health state, etc. Moreover, in insects, pheromones alone can directly control reproductive behavior, whereas in vertebrates, a combination of different sensory stimuli (visual, tactile, chemical, etc.) is often required to control reproduction. Therefore, in vertebrates, pheromones may be better defi ned as a group of active compounds in a secretion that supply information to conspecifi cs that may be relevant for reproductive decisions (for reviews see Mason 1992; Wyatt 2003, 2010; Müller-Schwarze 2006; Apps 2013).
