Contribution to the mitogenome diversity in Delphacinae: Phylogenetic and ecological implications.

We document the complete (or nearly complete) mitogenomes of 20 Delphacidae taxa, and together with 17 other delphacid mitogenomes currently in GenBank, to reconstruct the phylogeny of the Delphacinae and to investigate mitogenome differences among members of Delphacini, Tropidocephalini and Saccharosydnini. The mitogenomes of the 20 species encode the complete set of 37 genes usually found in animal mitogenomes. The length of complete mitogenomes in Delphacinae ranges from 15,531 to 16,231 bp. The gene order of all newly sequenced mitogenomes are identical, and the mitogenome gene order of Stenocranus matsumurai Metcalf in Stenocraninae has a transposition of tRNAThr. The two-clade system in Tropidocephalini was supported with high value (PP = 1, BS = 100), and the monophyly of Bambusiphaga was recovered in this study. Finally, we found that the host shift from plants with a C3 to a C4 photosynthetic pathway appears to have occurred independently in several clades.

First Record of the African Species Leptodelphax maculigera (Stål, 1859) (Hemiptera: Delphacidae) in Brazil.

This study reports the first occurrence of Leptodelphax maculigera (Stål, 1859) in Brazil and the Americas. Until now, this species has not been reported outside of Africa. The notification occurred in the State of Goiás in species of agronomic importance, as corn, Brachiaria, elephant grass, cultivar BRS Capiaçu and beans. The identification of the species was carried out through the morphological analysis of the male terminalia. This species has been found in maize plants, were sharing the same space with another wellknown species of great economic importance to crop, Dalbulus maidis (DeLong & Wolcott). Thus, the confirmed presence of L. maculigera in Brazil and the morphological distinction of the two species are key factors for establishing Integrated Pest Management (IPM) in the areas where it is found.

The Spread of Southern Rice Black-Streaked Dwarf Virus Was Not Caused by Biological Changes in Vector Sogatella furcifera.

The pandemic of Southern rice black-streaked dwarf virus (SRBSDV) in and after the late 2000s caused serious yield losses in rice in Southeast and East Asia. This virus was first recorded in China in 2001, but its exclusive vector insect, Sogatella furcifera, occurred there before then. To clarify the evolutionary origin of SRBSDV as the first plant virus transmitted by S. furcifera, we tested virus transmission using three chronological strains of S. furcifera, two of which were established before the first report of SRBSDV. When the strains fed on SRBSDV-infected rice plants were transferred to healthy rice plants, those established in 1989 and 1999 transmitted the virus to rice similarly to the strain established in 2010. SRBSDV quantification by RT-qPCR confirmed virus accumulation in the salivary glands of all three strains. Therefore, SRBSDV transmission by S. furcifera was not caused by biological changes in the vector, but probably by the genetic change of the virus from a closely related Fijivirus, Rice black-streaked dwarf virus, as suggested by ecological and molecular biological comparisons between the two viruses. This result will help us to better understand the evolutionary relationship between plant viruses and their vector insects and to better manage viral disease in rice cropping in Asia.

True Parthenogenesis and Female-Biased Sex Ratios in Cicadomorpha and Fulgoromorpha (Hemiptera, Auchenorrhyncha).

Insects are renowned for their remarkable diversity of reproductive modes. Among these, the largest non-holometabolous order, Hemiptera, stands out with one of the most diversified arrays of parthenogenesis modes observed among insects. Although there are extensive reviews on reproduction without fertilization in some hemipteran higher taxa, no such analysis has been conducted for the large suborders Fulgoromorpha (planthoppers) and Cicadomorpha (leafhoppers). In both groups, there are species that reproduce by true parthenogenesis, specifically thelytoky, and in Fulgoromorpha, there are species that reproduce by pseudogamy or, more specifically, sperm-dependent parthenogenesis. In this review paper, we give and discuss the only currently known examples of true parthenogenesis in Fulgoromorpha and Cicadomorpha, mainly from the planthopper family Delphacidae and the leafhopper family Cicadellidae. We analyze patterns of distribution, ecology, mating behavior, acoustic communication, and cytogenetic and genetic diversity of parthenoforms and discuss hypotheses about the origin of parthenogenesis in each case. We also highlight examples in which natural populations show a shift in sex ratio toward females and discuss possible causes of this phenomenon, primarily the influence of endosymbiotic bacteria capable of altering the reproductive strategies of the hosts. Our review is mainly based on studies in which the authors have participated.

New records of fifteen species of Fulgoromorpha (Insecta: Hemiptera) in Bulgaria.

Background: Bulgarian planthopper fauna (Hemiptera: Fulgoromorpha) are relatively well studied, with 164 known species from 77 genera and 11 families. Data for some species from previous studies were reported without any localities or were incomplete and need to be updated. New information: In the present study, 13 species of planthoppers are recorded for the first time in Bulgaria - Hyalesthesmlokosiewiczi Signoret, 1879 (Cixiidae), Delphaxarmeniacus Anufriev, 1970, Euidesspeciosa (Boheman, 1845), Eurysulalurida (Fieber, 1866), Florodelphaxparyphasma (Flor, 1861), Jassidaeuslugubris (Signoret, 1865), Metropisaris Asche, Drosopoulos & Hoch, 1983, Oncodelphaxpullula (Boheman, 1852), Ribautodelphaximitans (Ribaut, 1953), R.pungens (Ribaut, 1953), Stenocranusmajor (Kirschbaum, 1868) (Delphacidae), Latilicamaculipes (Melichar, 1906) and Tshurtshurnellaextrema Dlabola, 1980 (Issidae). Species from the following five genera are recorded in Bulgaria for the first time: Euides Fieber, 1866, Eurysula Vilbaste, 1968, Jassidaeus Fieber, 1866, Oncodelphax Wagner, 1963 (Delphacidae) and Latilica Emeljanov, 1971 (Issidae). As a result, the total numbers of known planthopper species and genera in Bulgaria become 177 species and 82 genera. The dataset of all collected specimens presented in this work was provided separately through Global Biodiversity Information Facility (GBIF). Detailed distribution of the species and comments on those from the European Red Lists are also provided.

Metabolite profiles of brown planthopper-susceptible and resistant rice (Oryza sativa) varieties associated with infestation and mechanical stimuli.

Understanding brown planthopper (BPH) resistance mechanism will expedite selective breeding of better BPH resistant lines of rice (Oryza sativa). Metabolic responses during BPH infestation derived from wound stress imposed by insect feeding, comparing with mechanical piercing will provide an insight into resistance mechanism in rice. Therefore, this study aimed to compare the metabolic responses of needle piercing treatment and BPH feeding treatment in BPH-susceptible (KD) and BPH-resistant (RH) varieties at four different time points (0, 6, 24 and 96 h) using liquid chromatography-high resolution mass spectrometry (LC-HRMS). Phenotypes of RH were not different among the treatments, whereas KD exhibited hopperburn symptom at 96 h post-BPH infestation. Principal component and cluster analyses revealed that metabolite profiles between KD and RH were different in response to both insect and mechanical stimuli. Metabolite profiles of RH under BPH and mechanical treatments at 24 and 96 h were different from the untreated, whereas metabolite profiles of KD after BPH infestation at 24 and 96 h were distinct from needle piercing and no treatment, suggesting that the resistant variety has an ability to adapt and defend both mechanical and insect stimuli. Metabolomics result showed that BPH infestation perturbed purine salvage biosynthesis (e.g., inosine, hypoxanthine) in both varieties, amino acid biosynthesis (e.g., phenylalanine, tryptophan) in KD, while the infestation perturbed lysine metabolism (pipecolic acid) and phenylpropanoid pathway (2-anisic acid) only in RH. BPH and mechanical stimuli perturbed phenylamide only in RH, but not in KD. These findings revealed that different rice varieties utilize different metabolites in response to insect and mechanical stimuli, resulting in different degrees of resistance.

Effects of Different Nutritional Conditions on the Growth and Reproduction of Nilaparvata lugens (Stål).

Growth and reproduction are the two most basic life processes of organisms and the distribution of energy in these processes is a core issue of the life history of organisms. Nilaparvata lugens (Stål), the brown planthopper (BPH), is a single-feeding rice pest. In the present study, this species was used as a model for testing the effects of nutritional conditions on various growth and reproduction indicators. First, the third-instar nymphs were fed with three different concentrations (100, 50, and 25%) of artificial diet until the second day of adulthood. The results showed that as the nutrient concentration decreased, the body development and oviposition of BPH were hindered. The total lipid content in the fat bodies was also significantly reduced. RT-PCR analysis showed compared to the 100% concentration group, the expression levels of vitellogenin (Vg) genes in the fifth-instar nymphs, adults, and in different tissues (ovary, fat body, and other tissues) were significantly decreased in the 50 and 25% treatment groups. Western blot analysis showed that Vg protein expression was highest in the 100% group, followed by the 50% group, with no expression in the 25% group. These results indicate that growth and reproduction in the BPH are regulated by, or correlated with, nutrient concentration. This study is of great significance as it reveals the adaptive strategies of the BPH to nutritional deficiencies and it also provides valuable information for the comprehensive control of this pest.

Adaptation by the Brown Planthopper to Resistant Rice: A Test of Female-Derived Virulence and the Role of Yeast-like Symbionts.

The adaptation by planthoppers to feed and develop on resistant rice is a challenge for pest management in Asia. We conducted a series of manipulative experiments with the brown planthopper (Nilaparvata lugens (Stål)) on the resistant rice variety IR62 (BPH3/BPH32 genes) to assess behavioral and bionomic changes in planthoppers exhibiting virulence adaptation. We also examined the potential role of yeast-like symbionts (YLS) in virulence adaptation by assessing progeny fitness (survival × reproduction) following controlled matings between virulent males or females and avirulent males or females, and by manipulating YLS densities in progeny through heat treatment. We found virulence-adapted planthoppers developed faster, grew larger, had adults that survived for longer, had female-biased progeny, and produced more eggs than non-selected planthoppers on the resistant variety. However, feeding capacity-as revealed through honeydew composition-remained inefficient on IR62, even after 20+ generations of exposure to the resistant host. Virulence was derived from both the male and female parents; however, females contributed more than males to progeny virulence. We found that YLS are essential for normal planthopper development and densities are highest in virulent nymphs feeding on the resistant host; however, we found only weak evidence that YLS densities contributed more to virulence. Virulence against IR62 in the brown planthopper, therefore, involves a complex of traits that encompass a series of behavioral, physiological, and genetic mechanisms, some of which are determined only by the female parent.

Regulation of Carbohydrate Metabolism by Trehalose-6-Phosphate Synthase 3 in the Brown Planthopper, Nilaparvata lugens.

Nilaparvata lugens (Stål) (Hemiptera: Delphacidae) is one of the pests that harm rice. In this paper, a new trehalose-6-phosphate synthase gene, TPS3, was identified by transcriptome sequencing and gene cloning. To explore its role in the energy metabolism of N. lugens we examined the carbohydrate contents at different stages of development, the tissue expression of TPS, and some physiological and biochemical indicators by injecting dsTPS3 and dsTPSs (a proportional mixture of dsTPS1, dsTPS2, and dsTPS3). The glucose content at the fifth instar was significantly higher than that in the fourth instar and the adult stages. The trehalose and glycogen contents before molting were higher than those after molting. TPS1, TPS2, and TPS3 were expressed in the head, leg, wing bud, and cuticle, with the highest expression in the wing bud. In addition, compared with the control group, the glucose content increased significantly at 48 h after RNA interference, and the trehalose content decreased significantly after 72 h. qRT-PCR showed that the expression level of UGPase decreased significantly at 48 h after injection, whereas GS expression increased significantly at 48 h after injecting dsTPS3. After dsTPS injection, the expression levels of PPGM2, UGPase, GP, and GS increased significantly at 72 h. After interfering with the expression of TPS3 gene alone, UGPase expression decreased significantly at 48 h, and GS expression increased significantly at 72 h. Finally, combined with the digital gene expression and pathway analysis, 1439 and 1346 genes were upregulated, and 2127 and 1927 genes were downregulated in the dsTPS3 and dsTPSs groups, respectively. The function of most differential genes was concentrated in sugar metabolism, lipid metabolism, and amino acid metabolism. The results indicated that TPS3 plays a key role in the energy metabolism of N. lugens and confirmed that TPS3 is a feasible target gene for RNA interference in N. lugens. Simultaneously, they provide a theoretical basis for the development and utilization of TPS3 to control pests.

A revision of the planthopper genus Chionomus Fennah (Hemiptera: Fulgoroidea: Delphacidae).

The planthopper genus Chionomus Fennah, 1971 (Hemiptera: Fulgoroidea: Delphacidae) currently includes three Neotropical species, removed from the polyphyletic genus Delphacodes Fieber, 1866. Morphological and molecular evidence further redefine Chionomus to include ten additional species (eight species removed from Delphacodes, two described as new, viz. Chionomus dolonus n. sp. and C. herkos n. sp.), with another four species synonymized. Phylogenetic analyses of morphological and molecular sequence data of the mitochondrial gene Cytochrome Oxidase I provide support for the monophyly of Chionomus. We use a mixed model Bayesian optimality criterion to define phylogenetic relationships among Chionomus and support paraphyly of the original definition of Chionomus (with respect to Delphacodes) and monophyly of the revised genus.

The complete mitochondrial genome of Unkanodes sapporonus (Hemiptera: Delphacidae).

In this study, we sequenced and analyzed the complete mitochondrial genome of Unkanodes sapporonus (Matsumura) (Hemiptera: Delphacidae). The mitogenome was 17,765 bp in length with A + T content of 75.87%, containing 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region. All protein-coding genes started with ATN, except for nad5, which used noncanonical codon GTG. All tRNAs could fold into typical clover-leaf secondary structures, with the exception of trnS1 (AGN).

A New Species of Abbrosoga (Hemiptera: Fulgoroidea: Delphacidae), An Endemic Puerto Rican Planthopper Genus, with an Updated Checklist of the Delphacidae of Puerto Rico.

The genus Abbrosoga Caldwell (Delphacidae: Delphacinae: Delphacini) was described in Caldwell Martorell (1951) to include the single species Abbrosoga errata Caldwell, 1951. Here, a second species, Abbrosoga multispinosa n. sp. is described. Revised diagnostics are presented for the genus and A. errata, including a key to species. A compiled list of 64 delphacid species from Puerto Rico is presented, with updated nomenclature, including the new species and a new record of Delphacodes aterrima for Puerto Rico.

A New Genus and Species of Delphacidae (Hemiptera: Fulgoroidea: Delphacidae) from Costa Rica.

Melaniphax suffusculus gen. et sp. nov. is described from Costa Rica, representing the 57th delphacid species recorded from the country to date. The new genus is superficially similar to Caenodelphax Fennah in general appearance in that the body is uniformly colored with the wings infuscated. Distinctive features of the new taxon include simple, forceps-like gonostyli, a broadly compressed aedeagus with large serrate lateral flanges, and the anal tube bearing a pair of short, stout, truncate, caudally-directed processes on the ventro-caudal margin and slender, elongate processes from the antero-ventral margin.

The complete mitochondrial genome of Laodelphax striatellus (Fallén, 1826) (Hemiptera: Delphacidae) collected in a mid-Western part of Korean peninsula.

Laodelphax striatellus (Fallén, 1826) is one of key rice pests in Northeast Asia. We have determined the mitochondrial genome of L. striatellus collected in a mid-western part of Korean peninsula. The circular mitogenome of L. striatellus is 16,359 bp long including 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNAs, and a single large non-coding region of 1,972 bp. The base composition was AT-biased (77.3%). In comparison of the two Chinese L. striatellus mitogenomes with Korean mitogenome, total 140 and 40 single nucleotide polymorphisms and 166 and 118 insertions and deletions were identified, presenting intra-species variations based on geographical distribution.

The complete mitochondrial genome of Laodelphax striatellus (Fallén, 1826) (Hemiptera: Delphacidae) collected in a southern part of Korean peninsula.

A 16,359 bp mitochondrial genome of Laodelphax striatellus collected in a southern part of Korean peninsula was completed and their intraspecies variations were compared with Korean and Chinese L. striatellus mitogenomes. The circular mitogenome of L. striatellus contains 13 protein-coding genes, two rRNA genes, 22 tRNAs, and a single large non-coding region of 1,972 bp. The base composition was AT-biased (77.3%). It has only one single nucleotide polymorphism (SNP) in AT-rich region compared to other Korean mitogenome, but total 41 and 141 SNPs and 118 and 166 insertions and deletions, respectively, compared to two Chinese mitogenomes, suggesting the possibility of tracing migration based on geographic genetic diversity.

Sequencing and analysis of the complete mitochondrial genome of Changeondelphax velitchkovskyi (Hemiptera: Fulgoroidea).

We determined the complete mitochondrial genome sequence of Changeondelphax velitchkovskyi (Melichar 1913). The complete mitogenome sequence of C. velitchkovskyi was observed to be a circular molecule 16,449 bp long and consists of 13 protein-coding genes (PCG), two ribosomal RNA (rRNA) genes and 22 transfer RNA (tRNA) genes (GenBank accession no. MG049916). This nucleotide composition is biased toward adenine and thymine (75.7% A + T). The A + T-rich region is found between rrnS and trnI, and this entire region was 1781 bp long.

A review of New World Malaxa (Hemiptera: Fulgoroidea: Delphacidae).

The New World species attributed to the genus Malaxa Melichar (Hemiptera: Fulgoroidea: Delphacidae) are reviewed with special reference to the type species Malaxa acutipennis from the Philippines. We provide an amended diagnosis for Malaxa acutipennis contrasted with the genus delineation presented for Chinese Malaxa, most recently by Hou et al. (2013). We find Malaxa to be an Old World genus and segregate New World species into two new genera, Lamaxa and Xalama, diagnosed most readily by proportions of the antennae and features of the terminalia. Both Lamaxa and Xalama are uncommonly encountered. Lamaxa is distributed widely through the Neotropics, whereas Xalama is heretofore known only from Bolivia and Peru.

The complete mitochondrial genome sequence of the corn planthopper, Peregrinus maidis (Hemiptera: Fulgoroidea).

In this study, we analyzed the complete mitochondrial genome sequence of the corn planthopper, Peregrinus maidis. The complete mitogenome sequence of P. maidis was observed to be a circular molecule 16,279 bp long and consisting of 13 protein-coding genes (PCG), 2 ribosomal RNA (rRNA) genes and 22 transfer RNA (tRNA) genes (GenBank accession no. MG049917). The nucleotide composition is biased toward adenine and thymine (77.8% A + T). The A + T-rich region was found between rrnS and trnI, and this entire region was 1596 bp long.

Antagonism of entomopathogenic fungi by Bacillus spp. associated with the integument of cicadellids and delphacids.

Entomopathogenic fungi are potential tools to biocontrol cicadellids and delphacids, two groups of insects that cause extensive damage to agricultural crops. However, bacteria living on the host cuticle may inhibit fungal growth. In the present work, following the molecular characterization of 10 strains of Bacillus isolated from the integument of cicadellids and delphacids, we selected isolates of the fungi Beauveria bassiana and Metarhizium anisopliae that are resistant to the antimicrobials secreted by these bacterial strains. The antagonistic activity of the 10 bacterial isolates belonging to the genus Bacillus (i.e., B. amyloliquefaciens, B. pumilus, and B. subtilis) against 41 isolates of Bea. bassiana and 20 isolates of M. anisopliae was investigated in vitro on tryptic soy agar using the central disk test. With this approach, isolates of Bea. bassiana and M. anisopliae resistant to antagonistic bacteria were identified that can be further developed as biological control agents.

The planthopper genus Spartidelphax, a new segregate of Nearctic Delphacodes (Hemiptera, Delphacidae).

The new genus Spartidelphax is described to house three species removed from the polyphyletic genus Delphacodes. The members of Spartidelphax are coastal species native to eastern North America, and probably feed exclusively on cordgrass (Poaceae, Spartina Schreb.). The taxonomy and nomenclature of the included species (viz. Spartidelphaxdetectus, Spartidelphaxluteivittus, and Spartidelphaxpenedetectus) are reviewed. Spartidelphaxluteivittus is a nomen dubium, whose type material is inadequate to provide diagnostic features contrasting with Spartidelphaxdetectus and Spartidelphaxpenedetectus. Diagnoses and a key are provided for the remaining Spartidelphax.