Historical biogeography of the widespread spider wasp tribe Aporini (Hymenoptera: Pompilidae)

AimOur aim was to determine the age and area of origin of the genera of the Aporini tribe of spider wasps by studying its historical biogeography. We also tested the fit of several hypotheses concerning the processes underlying the widespread distribution of this group. LocationThe Holarctic and Neotropics. MethodsA phylogeny of 44 Aporini taxa was produced through Bayesian inference using four nuclear molecular markers (elongation factor-1 F2 copy, long-wavelength rhodopsin, wingless and the D2-D3 regions of the 28S ribosomal RNA). A lognormal relaxed molecular clock, calibrated with ages from three fossils, was used to estimate lineage divergence times. Biogeographical processes were studied using three methods: statistical dispersal-vicariance analysis (S-DIVA), dispersal-extinction cladogenesis (DEC) analysis and Bayesian binary Markov chain Monte Carlo (BBM) analysis. ResultsOur data suggest an origin for the most recent common ancestor of extant Aporini in the Nearctic region in the early Miocene, 22.6Ma, with a confidence interval (CI) of17.40-28.83Ma. All genera originated in the Miocene, four in the Nearctic region. A constrained DEC analysis, where only dispersal to adjacent regions was allowed, produced the highest likelihood and was mostly congruent with the BBM results. Main conclusionsDispersal from the Nearctic region to the Palaearctic region probably occurred across the Bering land bridge in the early Miocene, 15-18Ma (CI=11.14, 23.52), while three dispersal events to South America from Mesoamerica took place independently. These dispersals to South America occurred after 18Ma through the Isthmus of Panama or across the Panama seaway. Three independent over-water dispersal events to the Antilles occurred from Mesoamerica and the Nearctic for two Aporini genera. The patterns inferred within the biogeographical history of Aporini agree with several scenarios proposed for other unrelated taxa.