Le comportement social des urodèles

It could be misleading to consider that the social behaviour of newts and salamanders is simple and can be generalized. Indeed, individuals are faced with external and internal conditions which are extremely variable. In response to these factors, they may respond in a particular way. The behavioural variations, called alternative tactics, allow individuals to improve their fitness, i.e. to ensure the survival of their genes. They can be exhibited in reaction to a large range of factors such as the mere presence or density of competitors, the operational sex-ratio, the behaviour and kinship of the other individuals, the abiotic characteristics of the environment, the experience of the individuals involved. These alternative tactics are favoured in urodeles. Indeed, although the main process of fertilization is internal, they breed by means of a spermatophore deposited in the external environment. Each species of newts and salamanders exhibits specific behavioural patterns as they developed and evolved in particular environments which have exerted selective pressures on the individuals and in this way on the species. As a consequence, the understanding of patterns of behaviour requires that we know the environment in which they appeared. The main occurrence of parental care and territoriality in terrestrial environments may be explained by the features of these habitats in which eggs could not survive without protection, and in which adults may defend areas of particular interest and communicate by means of pheromones. All of these characteristics show that we have to study the behaviour of individuals of different species under several conditions. Without such an analysis, it would be difficult to understand biodiversity.