MEYLAN, S.*; CLOBERT, J.; de FRAIPONT, M.: maternal stress and juvenile dispersal in the common lizard

The causes of phenotypic variation among individuals are of interest to many scientists in Evolutionary Ecology. A phenotype results from genetic and environmental influences. We are interested in the influences of maternal environment on phenotypic variation in natal dispersal. Offspring natal dispersal, as are other life history traits, is influenced by prenatal environment. An adaptive maternal control of offspring behavior may promote offspring fitness in temporally predictable environments. Conversely, maternal effects could be maladaptive due to the time lag of the response to selection. In the common lizard Lacerta vivipara, a suite of experiments has shown that maternal condition during gestation affects juvenile dispersal, and we hypothesized that the condition of the mother reflects her own health (i.e. her future survival prospects) rather than the quality of the environment. Furthermore, Kin competition was shown to be very important in shaping natal dispersal in common lizards. To explore this hypothesis, we induced stress in pregnant females by application of corticosterone and we measured dispersal and morphology of juveniles. No effect was found on morphology. However, offspring dispersal from stressed mothers was decreased for large-sized (old) mothers, and increased for small-sized (young) females. So, female age influenced the stress effect, and one can argue that corticosterone is not the only factor affecting the development of the dispersal phenotype.