The widespread leafhopper genus Scaphoideus Uhler is the most diverse genus in Scaphoideini and includes some species that are serious pests and vectors of plant pathogens. Here the first Scaphoideus mitogenome sequences are provided for three species, S. maai, S. nigrivalveus and S. varius, representing three main species groups in the Oriental region based on color pattern. The lengths of these three mitogenomes were 15,188, 15,235 and 15,207 bp, respectively. Gene order of three mitogenomes is highly conserved and identical to that of the putative ancestral insect. All three mitogenomes exhibited similar AT nucleotide bias, AT-, GC-skews and codon usage. One large 101 bp intergenic spacer between trnY and cox1 was in S. varius. All 22 tRNA genes had typical cloverleaf secondary structures, except for trnS1 (AGN) which appears to lack the dihydrouridine arm. Genes atp8, nad6 and nad2 were highly variable while cox1 showed the lowest nucleotide diversity. Phylogenetic analyses of three concatenated nucleotide datasets using maximum likelihood and Bayesian methods, comprising all 13 mitogenomes currently available for Membracoidea plus mitogenomes for eight outgroup species representing other cicadomorphan superfamilies, yielded the same topology in which Scaphoideus species formed a monophyletic group within a larger clade comprising three other included Deltocephalinae.

Only six mitochondrial genomes (mitogenomes) have been previously published for Cicadellidae, the largest family of Hemiptera. This study provides complete, annotated mitogenomes of two additional cicadellid, species Maiestas dorsalis and Japananus hyalinus, and the first comparative mitogenome analysis across the superfamily Membracoidea. The mitogenomes of both sequenced species are similar to those of other studied hemipteran mitogenomes in organization and the lengths are 15,352 and 15,364 bp with an A + T content of 78.7% and 76.6%, respectively. In M. dorsalis, all sequenced genes are arranged in the putative ancestral insect gene arrangement, while the tRNA cluster trnW-trnC-trnY is rearranged to trnY-trnW-trnC in J. hyalinus, the first reported gene rearrangement in Membracoidea. Phylogenetic analyses of the 11 available membracoid mitogenomes and outgroups representing the other two cicadomorphan superfamilies supported the monophyly of Membracoidea, and indicated that treehoppers are a derived lineage of leafhoppers. ML and BI analyses yielded topologies that were congruent except for relationships among included representatives of subfamily Deltocephalinae. Exclusion of third codon positions of PCGs improved some node support values in ML analyses.

Mouthparts are among the most important sensory and feeding structures in insects and comparative morphological study may help explain differences in feeding behavior and diet breadth among species. The spotted lanternfly Lycorma delicatula (White) (Hemiptera: Fulgoromorpha: Fulgoridae) is a polyphagous agricultural pest originating in China, recently established and becoming widespread in Korea, and more recently introduced into eastern North America. It causes severe economic damage by sucking phloem sap and the sugary excrement produced by nymphs and adults serves as a medium for sooty mold. To facilitate future study of feeding mechanisms in this insect, the fine-structural morphology of mouthparts focusing on the distribution of sensilla located on the labium in adult L. delicatula was observed using a scanning electron microscope. The mouthparts consist of a small cone-shaped labrum, a tubular labium and a stylet fascicle consisting of two inner interlocked maxillary stylets partially surrounded by two shorter mandibular stylets similar to those found in other hemipteran insects. The five-segmented labium is unusual (most other Fulgoromorpha have four segments) and is provided with several types of sensilla and cuticular processes situated on the apex of its distal labial segment. In general, nine types of sensilla were found on the mouthparts. Six types of sensilla and four types of cuticular processes are present on sensory fields of the labial apex. The proposed taxonomic and functional significance of the sensilla are discussed. Morphological similarities in the interlocking mechanism of the stylets suggest a relationship between Fulgoromorpha and Heteroptera.