Are dispersal-dependent behavioral traits produced by phenotypic plasticity?

Dispersal is a common response to deteriorating conditions such as intense competition, food limitation, predation or parasitism. Although it provides obvious advantages, dispersal is often assumed to be costly. Selection is therefore likely to have acted to decrease these costs, and indeed several studies demonstrated that dispersers and philopatric individuals differ in their morphology, physiology and/or behavior. Using the common lizard (Lacerta vivipara) as our model system, we examined the contribution of phenotypic plasticity to the establishment of dispersal-dependent behavioral traits. We used a reciprocal transplant experiment in which conditions at the maternal site of origin, during offspring development in utero, and at the release site were manipulated. We then compared activity, social interactions and foraging behavior between individuals that stayed philopatric and those that dispersed. Most behavioral traits were also measured at birth and after the dispersal phase.This study demonstrates that (a) 10 months after the dispersal phase, there were still marked behavioral differences between dispersing and philopatric individuals, (b) the reaction when confronted to another individual was also dispersal-status dependent, a result which strongly suggests that individuals are able to recognize the dispersal status of same-age conspecifics and (c) none of the behavioral characteristics were found to be dependent on the environmental conditions (maternal and natal environment) indicating a lack of phenotypic plasticity in the building of the dispersal-dependent behavioral traits examined.