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)

Abstract

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.

Genetic variation and bidirectional gene flow in the riparian plant Miscanthus lutarioriparius, across its endemic range: implications for adaptive potential

“…Genetic diversity plays an important role in the adaptation capabilities of species and their susceptibility to environmental changes (Raymond et al ., ). Measurements of the relationship between genetic variation and adaptive traits have already been conducted in a number of species, which showed that species with high level of genetic diversity and gene flow have higher phenotypic plasticity (Reed & Frankham, ; Ghalambor et al ., ; Gruber et al ., ).…”

Molecular taxonomic analysis of the plant associations of adult pollen beetles (Nitidulidae: Meligethinae), and the population structure ofBrassicogethes aeneus

“…This 186 region has been widely applied in studies of beetle phylogenetics, phylogeography and DNA taxonomy because it is more easily amplified in some taxa and can contain greater phylogenetic 188 signal than the standard Folmer barcode region of the same gene (Cardoso and Vogler, 2005;Gómez-Zurita et al, 2010;Kubisz et al, 2012 Raymond et al, 2013;Stefanescu et al, 2013;BC Williams, 1951 and Greece) were included to provide a preliminary assessment of haplotype variation for a region known to support high diversity in many widespread European taxa (e.g. Hewitt, 2000;Stone et al, 272 2012;Taberlet et al, 1998).…”

Combination of morphometric and isotopic tools for studying spring migration dynamics in Episyrphus balteatus

“…Finally, morphological differences are also often associated with genetic structure (Villemant et al 2007, Francoy et al 2011, Vicente et al 2011, Neto et al 2013. However, previous studies found no evidence for genetic structure either in relation with geographical origin (Hondelmann et al 2005, Raymond et al 2013b, or with overwintering strategy (Raymond et al 2013a) in E. balteatus. This lack of genetic structure may reduce the degree of morphological variation between individuals originating from different regions or using different overwintering strategies.…”

“…Although most aphidophagous hoverfly species are migratory and provide ecosystem services that are important for agriculture, issues related to migration have rarely been addressed in these species. Lack of genetic differentiation between E. balteatus overwintering strategies (Raymond et al 2013a) as between geographical origins (Hondelmann et al 2005, Raymond et al 2013b leads to consider alternative approaches to understand migration patterns of this species.…”