Evaluation of biogeography and flight behavior in Odonata using phylogenomics
Dragonflies and damselflies (Insecta: Odonata) are descended from what were most likely the first winged animals, which flew 320 million years ago (Ma). They comprise 6400 extant species distributed on every continent except Antarctica. Examination of long-standing hypotheses regarding the role of flight behavior and wing morphology in shaping the global distribution of odonates has been limited by spatial and taxonomic scope. Here we leverage mobilized trait and distribution data from specimens and literature combined with a uniquely comprehensive target-enriched phylogeny (940 loci) covering all families and 67% of genera. Divergence time estimation suggests the crown age of Odonata to be 290-325 Ma. Bayesian biogeographical evolutionary analysis of nine biogeographical regions provides a preliminary biogeographical history for odonates spanning 325 Ma. Key family-level splits occurred during the Jurassic and Cretaceous, paralleling the increasing isolation of landmasses and the poleward drift of the contemporary Australasian and Holarctic regions. Ancestral reconstruction of flight behavior strategies (flyer v. percher) suggests the odonate ancestor was a flyer, spending a majority of its time on the wing, with multiple independent transitions to percher; several transitions back to the flyer flight behavior have also occurred. We measured aspect ratios for forewings and hindwings and used a comparative framework to show a strong relationship between aspect ratio and perching and flying behavioral strategies. Both behavioral and morphological adaptation likely facilitated the distributional success of select odonate lineages. Our study lays the foundation for a revised classification of odonates and a more complete understanding of the influence of flight behavior and wing morphology in relation to evolutionary processes shaping past and current odonate diversity.