Salix transect of Europe: structured genetic variation and isolation-by-distance in the nettle psyllid, Trioza urticae (Psylloidea, Hemiptera), from Greece to Arctic Norway

Abstract

BackgroundThe common nettle (Urtica dioica L.) is co-associated with willows (Salix spp.) in riparian habitats across Europe. We sampled the widespread nettle psyllid, Trioza urticae (Linné, 1758), from Urtica in 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.New informationPhylogeographic analysis using DNA sequences of two mtDNA regions, COI and cytB, shows that T. urticae specimens 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.

Salix transect of Europe: additional leaf beetle (Chrysomelidae) records and insights from chrysomelid DNA barcoding

“…1) clusters with the southern clade. The absence of clear phylogeographic patterns in the chrysomelids is similar to our findings for curculionids (Canty et al in review), but differs from those found in a hemipteran taxon (the nettle psyllid; Psylloidea, Hemiptera) sampled along the transect in which population structure suggests distinct regional clades (Wonglersak et al 2017).…”

DNA Barcoding Highlights Cryptic Diversity in the New Zealand Psylloidea (Hemiptera: Sternorrhyncha)

“…The application of different species delimitation methods produced different results, sometimes in contrast with each other. This suggest that, despite being broadly used for psyllids [12,29,49], a COI 3% uncorrected p-distance between taxa should be combined with at least a species delimitation method, such as ABGD or GMYC, to be considered indicative of species separation. Surely, integration of COI barcoding, different species delimitation methods, and information from host plant association and morphology resulted to be a quick and valuable approach for identification of New Zealand psyllids.…”

“…Based on a 3% uncorrected p-distance threshold for COI divergence, which is widely used today for the identification of psyllids [12,29,49], 89 taxa could be delimited in the COI dataset. This highlighted an unexpectedly high level of cryptic diversity.…”

Revision of the Hawaiian psyllid genus Swezeyana, with descriptions of seven new species (Hemiptera, Psylloidea, Triozidae)

“…2). In addition, it is interesting to compare maximum intraspecific divergence for two widespread non-Hawaiian taxa, Trioza urticae (Linné, 1758) (the common nettle psyllid): 2.8%, sampled from across Europe (southern Greece to arctic Norway, ~3500 km) (Wonglersak et al 2017), and Mesohomotoma hibisci : 13.7%, a Pacific-wide species sampled from Singapore, New Caledonia, and French Polynesia (~7000 km and ~4500 km) (Percy 2017a); these two extremely widespread taxa are distributed over similarly large distances, but one is an almost entirely terrestrial landscape, whereas the other is an oceanic island landscape. The data indicates there is surprisingly efficient dispersal over large terrestrial distances (in this case facilitated by a highly abundant host plant, the common nettle, Urtica dioica ), and in contrast relatively poor dispersal across oceans (despite the host plant, in this instance, Hibiscus tiliaceus , being abundant in nearly all Pacific regions).…”