Fidelity to the breeding site in the alpine newt Triturus Alpestris.

In a context of several closed breeding sites (archipelago model), the great majority of alpine newts are sedentary, visiting the same site during two successive years. A homing experiment offered the animals a choice between two breeding sites, one from which they came and the other which was inhabited by another population. This experiment demonstrates the fidelity of a great majority of newts for their site of origin. Fidelity was stronger when sites were distant (150 m) than when nearer (25 m). The speed and the probability of return still varied according to both the distance and the nature of the environment of the release point. The performances were better when the animals were released in the wood than when released in the pasture. The mechanisms of orientation and navigation which should explain such results, as well as the genetic consequences of the fidelity, are examined and discussed.