Maternal size and stress and offspring philopatry: An experimental study in the common lizard (Lacerta vivipara)

During gestation, many morphological, physiological, and behavioural traits are influenced by the maternal environment. Previous experiments on natal dispersal in Lacerta vivipara demonstrated that maternal condition during gestation affects juvenile dispersal behaviour. The mechanisms by which a female may influence her offspring, or offspring respond to changes in the mother's internal environment, remain largely unknown. In this study, we investigated the role of corticosterone during pregnancy on the production of the dispersal phenotype. Ninety pregnant females were collected from a population at Cevennes (Massif Central) and kept in the laboratory until parturition. We applied a corticosterone solution daily on the back of 58 females and applied a similar solution, but without corticosterone, to the 32 others as a control. We measured dispersal propensity and morphology of the offspring of both groups. Morphology of offspring was not affected by hormonal treatment of their mothers, but dispersal of young from corticosterone-treated mothers was significantly smaller for large-sized (old) mothers and significantly greater for small-sized (young) females compared to the offspring of control females. Corticosterone might not be the only factor affecting the development of the juvenile dispersal phenotype. Maternal effects on juvenile dispersal reflect future survival prospects of the female and/or the quality of her environment; this finding strengthens our previous finding that natal dispersal in L. vivipara results from the integration of multiple factors.