Salixtransect of Europe: structured genetic variation and isolation-by-distance in the nettle psyllid,Trioza urticae(Psylloidea, Hemiptera), from Greece to Arctic Norway.
BACKGROUND
The common nettle (Urtica dioicaL.) is co-associated with willows (Salixspp.) in riparian habitats across Europe. We sampled the widespread nettle psyllid,Trioza urticae(Linné, 1758), fromUrticain willow habitats on a megatransect of Europe from the Aegean to the Arctic Ocean. The aim of this study was to use an unusually widespread insect to assess the influence of geographic distances and natural geographic barriers on patterns of genetic variation and haplotype distribution.


CONCLUSIONS
Phylogeographic analysis using DNA sequences of two mtDNA regions, COI and cytB, shows thatT. urticaespecimens are organized into four regional groups (southern, central, northern and arctic). These groups are supported by both phylogenetic analysis (four geographically-based clades) and network analysis (four major haplotype groups). The boundary between southern and central groups corresponds to the Carpathian Mountains and the boundary between the central and northern groups corresponds to the Gulf of Finland. Overall these groups form a latitudinal cline in genetic diversity, which decreases with increasing latitude.
University College London, London, United Kingdom.
Rungtip
R
Wonglersak
University of British Columbia, Vancouver, Canada.
Quentin
Q
Cronk
Natural History Museum, London, United Kingdom.
Diana
D
Percy
 Triozidae ; biogeography; haplotype network; isolation by distance; latitudinal cline; megatransect