Mitogenomic Analysis and Phylogenetic Implications for the Deltocephaline Tribe Chiasmini (Hemiptera: Cicadellidae: Deltocephalinae).

The grassland leafhopper tribe Chiasmini (Cicadellidae: Deltocephalinae) presently comprises 324 described species worldwide, with the highest species diversity occurring in the Nearctic region but a greater diversity of genera occurring in the Old World. In China, this tribe comprises 39 described species in 11 genera, but the fauna remains understudied. The complete mitogenomes of three species of this tribe have been sequenced previously. In order to better understand the phylogenetic position of Chiasmini within the subfamily Deltocephalinae and to investigate relationships among Chiasmini genera and species, we sequenced and analyzed the complete mitogenomes of 13 species belonging to seven genera from China. Comparison of the newly sequenced mitogenomes reveals a closed circular double-stranded structure containing 37 genes with a total length of 14,805 to 16,269 bp and a variable number of non-coding A + T-rich regions. The gene size, gene order, gene arrangement, base composition, codon usage, and secondary structure of tRNAs of the newly sequenced mitogenomes of these 13 species are highly conserved in Chiasmini. The ATN codon is commonly used as the start codon in protein-coding genes (PCGs), except for ND5 in Doratura sp. and ATP6 in Nephotettix nigropictus, which use the rare GTG start codon. Most protein-coding genes have TAA or TAG as the stop codon, but some genes have an incomplete T stop codon. Except for the tRNA for serine (trnS1(AGN)), the secondary structure of the other 21 tRNAs is a typical cloverleaf structure. In addition to the primary type of G-U mismatch, five other types of tRNA mismatches were observed: A-A, A-C, A-G, U-C, and U-U. Chiasmini mitochondrial genomes exhibit gene overlaps with three relatively stable regions: the overlapping sequence between trnW and trnC is AAGTCTTA, the overlapping sequence between ATP8 and ATP6 is generally ATGATTA, and the overlapping sequence between ND4 and ND4L is generally TTATCAT. The largest non-coding region is the control region, which exhibits significant length and compositional variation among species. Some Chiasmini have tandem repeat structures within their control regions. Unlike some other deltocephaline leafhoppers, the sequenced Chiasmini lack mitochondrial gene rearrangements. Phylogenetic analyses of different combinations of protein-coding and ribosomal genes using maximum likelihood and Bayesian methods under different models, using either amino acid or nucleotide sequences, are generally consistent and also agree with results of prior analyses of nuclear and partial mitochondrial gene sequence data, indicating that complete mitochondrial genomes are phylogenetically informative at different levels of divergence within Chiasmini and among leafhoppers in general. Apart from Athysanini and Opsiini, most of the deltocephaline tribes are recovered as monophyletic. The results of ML and BI analyses show that Chiasmini is a monophyletic group with seven monophyletic genera arranged as follows: ((Zahniserius + (Gurawa + (Doratura + Aconurella))) + (Leofa + (Exitianus + Nephotettix))).

Phylogenomics of the leafhopper genus Neoaliturus Distant, 1918 (Hemiptera: Cicadellidae: Deltocephalinae) reveals genetically divergent lineages in the invasive beet leafhopper.

Phylogenomic analysis based on nucleotide sequences of 398 nuclear gene loci for 67 representatives of the leafhopper genus Neoaliturus yielded well-resolved estimates of relationships among species of the genus. Subgenus Neoaliturus (Neoaliturus) is consistently paraphyletic with respect to Neoaliturus (Circulifer). The analysis revealed the presence of at least ten genetically divergent clades among specimens consistent with the previous morphology-based definition of the leafhopper genus "Circulifer" which includes three previously recognized "species complexes." Specimens of the American beet leafhopper, N. tenellus (Baker), collected from the southwestern USA consistently group with one of these clades, comprising specimens from the eastern Mediterranean. Some of the remaining lineages are consistent with ecological differences previously observed among eastern Mediterranean populations and suggest that N. tenellus, as previously defined, comprises multiple monophyletic species, distinguishable by slight morphological differences.

The Role of Plant Defense Signaling Pathways in Phytoplasma-Infected and Uninfected Aster Leafhoppers' Oviposition, Development, and Settling Behavior.

In plant-microbe-insect systems, plant-mediated responses involve the regulation and interactions of plant defense signaling pathways of phytohormones jasmonic acid (JA), ethylene (ET), and salicylic acid (SA). Phytoplasma subgroup 16SrI is the causal agent of Aster Yellows (AY) disease and is primarily transmitted by populations of aster leafhoppers (Macrosteles quadrilineatus Forbes). Aster Yellows infection in plants is associated with the downregulation of the JA pathway and increased leafhopper oviposition. The extent to which the presence of intact phytohormone-mediated defensive pathways regulates aster leafhopper behavioral responses, such as oviposition or settling preferences, remains unknown. We conducted no-choice and two-choice bioassays using a selection of Arabidopsis thaliana lines that vary in their defense pathways and repeated the experiments using AY-infected aster leafhoppers to evaluate possible differences associated with phytoplasma infection. While nymphal development was similar among the different lines and groups of AY-uninfected and AY-infected insects, the number of offspring and individual female egg load of AY-uninfected and AY-infected insects differed in lines with mutated components of the JA and SA signaling pathways. In most cases, AY-uninfected insects preferred to settle on wild-type (WT) plants over mutant lines; no clear pattern was observed in the settling preference of AY-infected insects. These findings support previous observations in other plant pathosystems and suggest that plant signaling pathways and infection with a plant pathogen can affect insect behavioral responses in more than one manner. Potential differences with previous work on AY could be related to the specific subgroup of phytoplasma involved in each case.

Karyotype and male pre-reductional meiosis of the sharpshooter Tapajosa rubromarginata (Hemiptera: Cicadellidae)

Cicadellidae in one of the best represented families in the Neotropical Region, and the tribe Proconiini comprises most of the xylem-feeding insects, including the majority of the known vectors of xylem-born phytopathogenic organisms. The cytogenetics of the Proconiini remains largely unexplored. We studied males of Tapajosa rubromarginata (Signoret) collected at El Manantial (Tucumán, Argentina) on native spontaneous vegetation where Sorghum halepense predominates. Conventional cytogenetic techniques were used in order to describe the karyotype and male meiosis of this sharpshooter. T. rubromarginata has a male karyological formula of 2n=21 and a sex chromosome system XO:XX (♂:♀). The chromosomes do not have a primary constriction, being holokinetic and the meiosis is pre-reductional, showing similar behavior both for autosomes and sex chromosomes during anaphase I. For this stage, chromosomes are parallel to the acromatic spindle with kinetic activities in the telomeres. They segregate reductionally in the anaphase I, and towards the equator during the second division of the meiosis. This is the first contribution to cytogenetic aspects on proconines sharpshooters, particularly on this economic relevant Auchenorrhyncha species. Rev. Biol. Trop. 59 (1): 309-314. Epub 2011 March 01.

Los Cicadellidae son una de las familias mejor representadas en la región neotropical. La tribu Proconiini incluye a muchos de los insectos que se alimentan de xilema y la mayoría de los vectores de organismos fitopatógenos asociados con dicho tejido de conducción. La citogenética de los Proconiini es prácticamente inexplorada. Por lo tanto, se utilizaron técnicas citogenéticas convencionales para describir el cariotipo y la meiosis en los machos de Tapajosa rubromarginata Signoret. Este cicadélido presenta el complemento cromosómico diploide de 2n=20A+X0 en los machos. Los cromosomas no presentan constricción primaria, son holocinéticos, y la meiosis es pre-reduccional, muestra un comportamiento similar tanto en los cromosomas sexuales como en los autosómicos durante la anafase I. En ese estado, los cromosomas se orientan de manera paralela a las fibras del huso acromático con actividad cinética en los telómeros y segregan de manera reduccional en la fase I y ecuacional en la fase II de la meiosis.

Populational fluctuation of vectors of Xylella fastidiosa, wells in sweet orange [Citrus sinensis (L. ) Osbeck] varieties of northwest Paraná State, Brazil

The aim of the present study was to assess the population flutuation of the sharpshooters species subfamily Cicadellinae belonging to the tribes Cicadellini and Proconiini, in sweet orange [Citrus sinensis( L). Osbeck] commercial orchards of the northwest region of Paraná State , Brazil. Samplings were carried out the employing every time 24 yellow sticky cards. Identification of the species showed that the most representative were Dilobopterus costalimai of the Cicadellini tribe and Acrogonia citrina of the Proconiini tribe.

A Clorose variegada dos citros (CVC) é uma importante doença que ocorre nos citros, cujo agente causal é a bactéria Xylella fastidiosa, Wells. A bactéria depende, obrigatoriamente, de insetos vetores para sua disseminação, que são as cigarrinhas sugadoras do xilema (Hemiptera: Cicadellidae, Cicadellinae). No presente estudo objetivou-se avaliar a flutuação populacional de espécies de cigarrinhas nas diferentes variedades de laranja doce [Citrus sinensis (L.) Osbeck], Natal, Pêra, Valência e Folha Murcha, em um pomar comercial localizado na região Noroeste do Paraná, no período de janeiro de 2000 a dezembro de 2002. Amostragens quinzenais foram realizadas com o uso de armadilhas adesivas amarelas, num total de 24 armadilhas em cada avaliação. Após a identificação das espécies observou-se, que as mais representativas foram Dilobopterus costalimai da tribo Cicadellini e Acrogonia citrina da tribo Proconiini, sendo que a variedade de laranja Pêra apresentou o maior número de espécies vetoras durante os anos avaliados.

Diversidade de Hemiptera Auchenorrhyncha em citros, café e fragmento de floresta nativa do Estado de São Paulo / Diversity of Hemiptera Auchenorrhyncha in citrus, coffee and a fragment of native forest of the State of São Paulo

The population of Hemiptera Auchenorrhyncha was studied in sweet citrus groves (Citrus sinensis), coffee plantations (Coffea arabica) and a semi-deciduous seasonal forest with shrub physiognomy in Bebedouro, SP, to evaluate the influence of the natural ecosystem on the species composition of the agroecosystems. Monitoring was carried out by using yellow stick cards, which were replaced every 15 days and all Auchenorrhyncha collected were counted and identified. Seven families, 11 subfamilies and 98 species were collected, with Cicadellidae being the most abundant. The native forest presented larger wealth, diversity and equitability of Auchenorrhyncha species, demonstrating to be more stable than the other habitats. The high values of similarities obtained between the agroecosystems and the forest demonstrated that great part of Auchenorrhyncha species occurring in the agricultural habitats was also occurring at the forest, indicating that the last may serve as reservoir of species. The abundance of the taxonomic groups of Auchenorrhyncha collected varied with the evaluated habitats, with Proconiini being the most abundant in the coffee plantation next to the forest, Athysanini, Scaphytopiini, Neocoelidiinae and Coelidiinae in the orange orchard and coffee plantation distant from the forest; Cicadellinae and Agalliinae were not related to any of the habitats. The presence of vector insects and possible vectors of plant diseases in the appraised habitats indicate the need of the implementation of strategies for landscape management.

A população de Hemiptera Auchenorrhyncha foi estudada em pomares de laranja doce (Citrus sinensis), cafezais (Coffea arabica) e floresta estacional semidecidual com fisionomia arbustiva, em Bebedouro (SP), com o objetivo de avaliar a influencia do ecossistema natural na composição de espécies do agroecossistemas. O monitoramento foi feito com cartões adesivos amarelos, os quais foram trocados a cada 15 dias, efetuando-se a contagem e identificação dos Auchenorrhyncha coletados. Capturou-se o total de sete famílias, 11 subfamílias e 98 espécies, sendo Cicadellidae o grupo mais abundante. A floresta nativa apresentou a maior riqueza, diversidade e equitabilidade de espécies de Auchenorrhyncha, demonstrando ser mais estável que os demais habitats. Os altos valores de similaridades obtidos entre os agroecossistemas e a floresta demonstram que grande parte das espécies de cigarrinhas que está ocorrendo nos habitats agrícolas também está ocorrendo na floresta, indicando que esta pode estar funcionando como reservatório de espécies. A abundância de grupos taxonômicos de Auchenorrhyncha coletados variou nos habitats avaliados, sendo Proconiini o mais abundante no cafezal próximo à floresta, Athysanini, Scaphytopiini, Neocoelidiinae e Coelidiinae no pomar de laranja e cafezal distante da floresta; Cicadellinae e Agalliinae não se relacionaram a nenhum dos habitats. A presença de insetos vetores e possíveis vetores de doenças de plantas cultivadas nos habitats avaliados indicam a necessidade da implantação do manejo de pragas nessa área.

Fauna de Homoptera: Auchenorrhyncha em Pomares de Ameixeira em Santa Catarina / Homoptera: Auchenorrhyncha Fauna of Plum Orchards in Santa Catarina State

The Homoptera: Auchenorrhyncha fauna of plum orchards in an area of epidemic spread of plum leaf scald disease in mid-west Santa Catarina State, Brazil were surveyed in 1991 and 1992 to search for plum leaf scald vectors. The homopterans were sampled by sweeping net and yellow water pan traps and when possible submitted to ELISA assay to detect Xylella fastidiosa bacteria. A total of 112 species were caught, distributed in the families Aethalionidae (1 species), Cercopidae (7), Cicadellidae (64), Cixiidae (3), Delphacidae (5), Issidae (2), Membracidae (18), Tropiduchidae (1) and Psyllidae (11). X. fastidiosa was detected in cicadellids Agallia spp. (two species), Balclutha hebe (Kirk.), Bucephalogonia xanthophis (Berg), Chlorotettix minimus (Baker), Exitianus obscurinervis (Stal), Haldorus sp., and Plesiommata corniculata Young; and in cercopids Deois schach (F.) and Deois flavopicta (Stal). The arborean cicadellids collected in water traps, like Dilobopterus dispar (Germar) and Oncometopia sp., could not be tested in ELISA assay because of their bad conditions of conservation.

A fauna de Homoptera:Auchenorrhyncha de pomares de ameixeira, situados numa área de disseminação da escaldadura-das-folhas no meio-oeste do estado de Santa Catarina, foi estudada durante 1991 e 1992 para se identificarem possíveis vetores da doença. Os homópteros foram coletados com rede de varredura e bandejas d'água amarelas e, quando possível, submetidos a teste ELISA para detecção da bactéria Xylella fastidiosa. Um total de 112 espécies foram capturadas, distribuídas nas famílias Aethalionidae (1 espécie), Cercopidae (7), Cicadellidae (64), Cixiidae (3), Delphacidae (5), Issidae (2), Membracidae (18), Tropiduchidae (1) e Psyllidae (11). A bactéria X. fastidiosa foi detectada nos cicadelídeos Agallia spp. (2 espécies), Balclutha hebe (Kirk.), Bucephalogonia xanthophis (Berg), Chlorotettix minimus (Baker), Exitianus obscurinervis (Stal), Haldorus sp. e Plesiommata corniculata Young; e nos cercopídeos Deois schach (F.) e Deois flavopicta (Stal). Os cicadelídeos arborícolas coletados em bandeja d'água, como Dilobopterus dispar (Germar) e Oncometopia sp., não puderam ser processados em teste ELISA em função do mal estado de conservação.

Nova espécie de Parabahita Linnavuori (Homoptera: Cicadellidae: Deltocephalinae)

A new species of Parabahita Linnavuori, 1959 is described and illustrated: Parabahita caudata sp. nov. (Brazil, Rondônia)

Uma nova espécie de Parabahita Linnavuori, 1959 é descrita e ilustrada: Parabahita caudata sp. nov. (Brasil, Rondônia)