Local adaptation and non-genetic maternal effects among three populations of Crepis sancta (Asteraceae)

Abstract

To test whether local adaptation occurs in the Mediterranean species Crepis sancta (Asteraceae), we performed reciprocal transplants among three populations inhabiting recently abandoned old fields. Initial seedling size before transplantation varied significantly among populations. Since these variations, which result in part from maternal environment effects, could lead to variation in plant performance, it was necessary to test for the consequences of non-genetic maternal effects on plant performance. One main feature of Crepis sancta is the morphological variation between peripheral and central achenes within each seed head. In particular, there are differences between morphs in seedling size, which are genetically independent. Therefore, the seed morph factor was used to control for maternal effects, in addition to initial seedling size. In two sites, the pattern of seedling mortality was consistent with the local adaptation hypothesis. Non-genetic maternal effects significantly influenced most adult traits, but data suggest that local adaptation was significant for at least one population. This study showed that local adaptation does exist in the colonising annual species Crepis sancta, but the phenomena is clearly not as strong as the advantage described for several perennial species occurring in stable environments.