Data from: Migration and dispersal may drive to high genetic variation and significant genetic mixing: the case of two agriculturally important, continental hoverflies (Episyrphus balteatus and Sphaerophoria scripta)

Population structure of pests and beneficial species is an important issue
when designing management strategies to optimize ecosystem services. In
this study, we investigated for the first time the population structure at
a continental scale of two migratory species of hoverflies providing both
pest regulation and pollination services [Episyrphus balteatus and
Sphaerophoria scripta (Diptera: Syrphidae)]. To achieve this objective, we
used two sets of 12 species-specific microsatellite markers on a
large-scale sampling from all over Europe. Our findings showed a high
level of genetic mixing resulting in a lack of genetic differentiation at
a continental scale and a great genetic diversity in the two species. All
the pairwise FST values between European localities were less 0.05 in the
two species. These low values reflect a large-scale genetic mixing
probably caused by the existence of frequent migratory movements in the
two species. Mantel tests revealed isolation-by-distance pattern on the
East–West axis, but not on the North–South axis. This
isolation-by-distance pattern confirms the existence of North–South
migratory movements in both directions and suggests an important step by
step dispersal. Population features shown by this study are common in
invasive species and pests, but are not often observed in beneficial
species. They reflect great colonization abilities and a high adaptive
potential when dealing with a changing environment. Our results highlight
the two studied species as particularly interesting beneficial insects for
pollination and pest predation in the current context of global change.