- 1Although little investigated, developmental processes that generate dispersal condition evolution of this behaviour. We have shown previously prenatal and postnatal influences on dispersal in the common lizard (Lacerta vivipara). The observation of these developmental processes was based on independent experiments; our primary goal in this paper is to test their interactions. Interactions could indeed be a source of inconsistencies in studies because they can mask, or even reverse, effects of factors treated additively.
- 2We studied dispersal of juveniles released in natura from 416 pregnant females captured in the field. We used a factorial design to test interactions among the maternal habitat (dry vs. humid), prenatal conditions (temperature, humidity), and postnatal environments (dry vs. humid).
- 3We found that juvenile dispersal was dependent on the humidity level at different developmental stages, but with varying and sometimes opposite effects. Dispersal was also influenced by the temperature during gestation and by populational differences not related to humidity (differences between replicated populations for the maternal and postnatal habitats).
- 4These results confirm our previous findings that dispersal of the common lizard is condition-dependent and has multiple causation. In addition, most of the effects exhibited interactions, and the ontogeny of dispersal appeared as a sequential process where the maternal habitat conditioned prenatal influences, and the prenatal environment modulated postnatal influences.
- 5The robustness of our results is supported by the finding of the same interactions in independent tests on both juvenile males and females. This militates in favour of future studies on the multiple causation of dispersal because the same dispersal status might originate from different causes, and different dispersal outcomes might be due to the same factor.