Macroecology and macroevolution of aquatic Coleoptera

The project aims to investigate the constraints that some habitat characteristics impose on the species living in them, and their effect in large scale macroevolutionary and macroecological patterns. The model system are species of aquatic Coleoptera, which are known to preferentially occupy one of two contrasting habitat types (running vs. standing waters). These habitat types, because of their different long-term persistence, pose different constraints on the populations living in them. Species living in the more stable running water habitats (measured in geological terms) are predicted to have lower dispersal abilities, with a higher persistence of local populations and a reduced gene flow among them. This should result in smaller range sizes and a higher evolutionary turnover. On the contrary, species living in standing water (typically more ephemeral geologically) are predicted to have higher dispersal abilities, with a higher instability of local populations and a more intense gene flow among them. This should result in larger geographical ranges and a slower evolutionary turnover when compared to species living in running waters. The project will test these predicted differences and their macroecological and macroevolutionary consequences along three lines. 1) Search for divergent patterns in the distribution of species richness of running vs. standing water species using published distribution maps of species of water beetles of families Dytiscidae and Hydraenidae, as well as other aquatic organisms. 2) Using molecular species level phylogenies, characterise the macroevolutionary parameters and trace the evolution of habitat preferences and of range size within Holarctic Hydroporini (Dytiscidae), the Agabus gr. of genera (Dytiscidae) and of some species groups within the genus Hydraena (Hydraenidae), with special emphasis in the West Mediterranean fauna. 3) Compare the phylogeographic genetic structure of selected species of running and standing water Dytiscidae, to test for predicted differences in geographic genetic structure and gene flow among distant populations.

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