Galápagos Giant Daisies

AAAS: “The genomic basis of adaptive leaf variation in the Galápagos giant daisies.” Since the time of Darwin + Wallace [in a different locale], we have known the Galápagos archipelago has long been a hotspot for adaptation. “Scalesia (Asteraceae) is the largest endemic plant genus of the Galápagos archipelago and an example of adaptive radiation.” While Scalesia species are highly varied in habit and morphology, most remarkable is their variety of leaf shapes, especially in the differential presence of leaf lobing/serration, a derived trait that evolved multiple times as a likely adaptation to the islands’ hot and dry equatorial climate.

“Bieker et al.combined genetic, transcriptomic, and morphometric data from 396 accessions encompassing the 15 species of Galápagos giant daisy in the genus Scalesia to better understand the phenotypic diversity seen across this genus.” Found that gene flow is limited, and some populations of the same species show relatively large degrees of differentiation despite morphological similarity, potentially supporting recategorization.

“Identified signatures of selection associated with leaf phenotypes, finding that similar leaf traits primarily arose through convergent evolution rather than introgression.” Findings have implications for the conservation of Scalesia’s threatened biodiversity, as unexpectedly high intra-specific genetic structure and long-term isolation among populations indicate widespread nascent speciation.

These results inform conservation efforts and illuminate features of plant adaptation on these iconic islands. Galápagos giant daisies are beautiful tropical plants demonstrating ongoing adaptation.

Source article: Nat. Commun. (2026) 10.1038/s41467–026–71865–3