Genomic, morphological and physiological data support fast ecotypic differentiation and incipient speciation in an...

Area of Science:

• Evolutionary Biology
• Ecology
• Genetics

Background:

• Alpine lineages exhibit complex genetic and phenotypic diversity due to evolutionary and demographic processes.
• Species delimitation and conservation planning are challenged by this diversity.

Purpose of the Study:

• To investigate the influence of Pleistocene climate changes and alpine adaptation on genomic and phenotypic variation in the Agabus bipustulatus species group.
• To understand the divergence patterns and speciation processes in alpine diving beetles.

Main Methods:

• Genomic data analysis (phylogenomics)
• Geometric morphometrics for phenotypic analysis
• Thermal tolerance experiments

Main Results:

• Identified three distinct lineages: two of Agabus bipustulatus (trans-Palearctic, Iberian) and one of Agabus nevadensis (Sierra Nevada endemic).
• Found evidence of genetic introgression and admixture, consistent with Quaternary climate-driven population dynamics.
• Suggested A. nevadensis is an alpine ecotype of A. bipustulatus, differentiated by genotype, morphology, and physiology due to isolation and altitudinal adaptation.

Conclusions:

• Fast ecotypic differentiation and incipient speciation are supported within the Agabus complex.
• Pleistocene glaciations and elevational adaptation are key drivers of alpine biodiversity.
• Unique ecotypic differentiation in Sierra Nevada populations highlights localized adaptation.