Morphological and DNA barcode species identifications of leafhoppers, planthoppers and treehoppers (Hemiptera:Auchenorrhyncha) at Barrow Island

Ten genetic clades detected among the nymphs were not observed among adultsand did not match pre-existing sequence accessions in GenBank or DNA barcode records in BOLD.Of the 73 adult Auchenorrhyncha species congruently identified by DNA barcoding and morphology,most were Cicadellidae (N = 53 morphospecies), the remaining 20 morphospecies were sparselyrepresentative of ten other families. Formal identifications to species level were available for only 36%of these 73 morphospecies, owing mainly to an absence of diagnostic male specimens within many ofthe delimited species. Indeterminate species detected among adults and nymphs are designated withinterim species codes.The work presented here demonstrates that DNA barcoding is likely to be a powerful investigative toolfor identifying and understanding species limits in the Auchenorrhyncha, particularly if it is used within anintegrative taxonomic framework.The hemipteran suborder Auchenorrhyncha comprises a rich assemblage of plant feedingspecies, many of which are widespread in distribution and act as vectors of viral and fungal diseasesaffecting plants. Species level identifications in this group generally are possible only by examination ofmale specimens; prior DNA barcode analyses of a limited range of Auchenorrhyncha indicate that thisapproach may provide an expedient means to identify species within this diverse group. In this studywe explored the utility of DNA barcoding for identification of a wider range of Auchenorrhyncha speciesthan has been examined previously. Diverse fulgoroid (planthopper) and membracoid (leafhopper andallies) Auchenorrhyncha were sampled from Barrow Island, Western Australia, and identified to the leastinclusive taxonomic units using morphology. DNA barcodes from 546 adult specimens were obtainedand analysed using a General mixed Yule â€Â' Coalescent (GMYC) modelling approach to genetically delimitputative species, as a comparison to the morphospecies identifications. Additional DNA barcodes (N =106) were obtained from nymphs and these were compared to adult DNA barcodes to identify speciespresent among immature specimens.Among adult specimens, 73 species were congruently delimited by morphology and genetic analyseswhen modelled using a single threshold GMYC. Congruence between morphological and molecularspecies assignments was greatly reduced when the Yule â€Â' Coalescent transition was allowed to varyacross genetic lineages. In a separate DNA barcode analysis of all specimens using neighbour joiningdistance metrics, nymphs and physically degraded specimens were in most cases genetically linked toadult conspecifics.