Data from: Inferences on population history of a seed chalcid wasp: invasion success despite a severe founder effect from an unexpected source population

Most invasive species established in Europe originate from either Asia or
North America, but little is currently known about the potential of the
Anatolian Peninsula (Asia Minor) and/or the Near East to constitute
invasion sources. Mediterranean forests are generally fragile ecosystems
that can be threatened by invasive organisms coming from different regions
of the Mediterranean Basin, but for which historical data are difficult to
gather and the phylogeographic patterns are still poorly understood for
most terrestrial organisms. In this study, we characterized the genetic
structure of Megastigmus schimitscheki, an invasive seed-feeding insect
species originating from the Near East, and elucidated its invasion route
in Southeastern France in the mid 1990’s. To disentangle the evolutionary
history of this introduction, we gathered samples from the main native
regions (Taurus Mountains in Turkey, Lebanon and Cyprus) and from the
invaded region, that we genotyped using five microsatellite markers and
for which we sequenced the mitochondrial Cytochrome Oxidase I gene. We
applied a set of population genetic statistics and methods, including
approximate Bayesian computation. We proposed a detailed phylogeographic
pattern for the Near East populations, and we unambiguously showed that
the French invasive populations originated from Cyprus, although the
available historical data strongly suggested that Turkey could be the most
plausible source area. Interestingly, we could show that the introduced
populations were founded from an extremely restricted number of
individuals that realized a host switch from Cedrus brevifolia to C.
atlantica. Evolutionary hypotheses are discussed to account for this
unlikely scenario.