Genetic Structure of Graphocephala atropunctata (Hemiptera: Cicadellidae) Populations Across Its Natural Range in California Reveals Isolation by Distance

Abstract

The genetic structure of 23 populations of Graphocephala atropunctata (Signoret) (Hemiptera: Cicadellidae: Cicadellinae), a vector of the plant pathogenic bacterium Xylellafastidiosa Wells et al., was investigated using ribosomal 28S and mitochondrial cytochrome C oxidase I gene sequences. The 28S sequences were identical across all G. atropunctata specimens and populations, but 16 mitochondrial haplotypes were detected and significant interpopulation differences were found in the distribution of these haplotypes. Pairwise estimates of Fst correlated positively with geographical distance between populations, a phenomenon known as genetic isolation by distance. Thus, despite potential for widespread movement of G. atropunctata through nursery and agricultural industries, isolated populations of G. atropunctata have remained genetically distinct, suggesting that negligible numbers of G. atropunctata are actually transported or population interbreeding rarely occurs. The phylogenetic relationship between G. atropunctata and two additional congeners, Graphocephala cythura Baker and Graphocephala flavovittata Metcalf, which have overlapping distributions with G. atropunctata, also was investigated. Although 28S sequences of G. flavovittata were strikingly similar to those of G. atropunctata, mitochondrial DNA (mtDNA) suggests that both species are genetically distinct from G. atropunctata.

Did maize domestication and early spread mediate the population genetics of corn leafhopper?

“…They can provide insight on historical processes mediating contemporary herbivorous pest distributions and host plant associations, including isolation events. Also, haplotype analyses are useful for reconstructing the evolutionary histories of populations (Ahern et al, 2009;Yuan et al, 2010;Ballman et al, 2011), and where populations are genetically structured, can be used to infer population ancestry on the basis of haplotype diversity and relationships (Havill et al, 2006). Additionally, haplotype analyses can provide insight on the origin of population genetic structuring by correlating the timing of population divergences with known isolation events (Ahern et al, 2009).…”

DNA Barcodes for Nearctic Auchenorrhyncha (Insecta: Hemiptera)

“…The only broad surveys are those of Kamitani [18], who provided DNA barcodes for 45 species of Japanese Cicadellidae, Cryan and Svenson [19] who included COI sequences for 80 species as part of their investigation of family-level relationships among Cercopoidea, and Lin & Wood [20] in a study of tribal relationships and the evolution of maternal care in Membracinae. In addition, several genus-level or species-group phylogenetic analyses and investigations of population variation have included all or part of the barcode region [21]–[32] providing intensive within-species replication. Two other studies employed COI barcodes to identify cicadellid prey items [33]–[34] while Le Roux and Rubinoff [35] used COI sequences to help determine the source of a leafhopper adventive to Hawaii.…”

Phylogeographic structure, outbreeding depression, and reluctant virgin oviposition in the bean thrips,Caliothrips fasciatus(Pergande) (Thysanoptera: Thripidae), in California

“…For example, the California native western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) was recently found to be comprised of two previously unrecognized, morphologically inseparable, cryptic species that occasionally co-occur on the same host plants (Rugman-Jones et al ., 2010). Similarly, the blue-green sharpshooter, Graphocephala atropunctata (Signoret) (Hemiptera: Cicadellidae), a native California pest of grapes, displays readily identifiable, population level variation in traits associated with communication, mating and genetic constitution, that may indicate incipient speciation (Ballman, 2009; Ballman et al ., 2011). These findings are interesting from a biological perspective because they raise questions about the concept of ‘species’ and the speciation process itself, but they also have important economic ramifications since accurate species identification is critical in the control of pest arthropods (Rosen, 1986; Davies et al ., 2004; Armstrong & Ball, 2005).…”