Increased pre-natal maternal corticosterone promotes philopatry of offspring in common lizards Lacerta vivipara

1. There is growing evidence that dispersal is highly phenotypically plasti c, i.e. that dispersal is condition-dependent. In the common lizard, disper sal has even been shown to be influenced by the maternal environment during pregnancy. Juveniles in good condition or issued from mothers in good cond ition disperse earlier or in higher numbers. 2. We hypothesized that plasma corticosterone was the proximate mechanism b y which condition and dispersal are linked, and tested this by manipulating the level of circulating corticosterone in pregnant females of the common lizard. 3. After parturition, we measured juvenile attractiveness towards the mothe r and juvenile dispersal of corticosterone (B) and placebo (P) implanted fe males. 4. Offspring of B females did disperse in lower number than those of P fema les. B offspring were also more attracted by the mother's odour than P offs pring. 5. In quite a few cases, the behavioural response of juveniles was dependen t on the interaction between the hormonal treatment and the mother snout-ve nt length or condition (body weight corrected for snout-vent length). 6. Corticosterone constitutes therefore one of the proximate mechanisms inv olved in the prenatal control of juvenile dispersal in this species. Along with other results, it is proposed that prenatal control of dispersal has e volved in order to avoid competition between mothers and their offspring.