Effect of Egg Rearing Temperature and Storage Time on the Biological Characteristics of the Predatory Stink Bug Podisus nigrispinus (Hemiptera: Pentatomidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Diploid chromosome set of kissing bug Triatoma baratai (Hemiptera, Triatominae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

De novo transcriptome assembly for a non-model species, the blood-sucking bug Triatoma brasiliensis, a vector of Chagas disease

High throughput sequencing (HTS) provides new research opportunities for work on non-model organisms, such as differential expression studies between populations exposed to different environmental conditions. However, such transcriptomic studies first require the production of a reference assembly. The choice of sampling procedure, sequencing strategy and assembly workflow is crucial. To develop a reliable reference transcriptome for Triatoma brasiliensis, the major Chagas disease vector in Northeastern Brazil, different de novo assembly protocols were generated using various datasets and software. Both 454 and Illumina sequencing technologies were applied on RNA extracted from antennae and mouthparts from single or pooled individuals. The 454 library yielded 278 Mb. Fifteen Illumina libraries were constructed and yielded nearly 360 million RNA-seq single reads and 46 million RNA-seq paired-end reads for nearly 45 Gb. For the 454 reads, we used three assemblers, Newbler, CAP3 and/or MIRA and for the Illumina reads, the Trinity assembler. Ten assembly workflows were compared using these programs separately or in combination. To compare the assemblies obtained, quantitative and qualitative criteria were used, including contig length, N50, contig number and the percentage of chimeric contigs. Completeness of the assemblies was estimated using the CEGMA pipeline. The best assembly (57,657 contigs, completeness of 80 %, < 1 % chimeric contigs) was a hybrid assembly leading to recommend the use of (1) a single individual with large representation of biological tissues, (2) merging both long reads and short paired-end Illumina reads, (3) several assemblers in order to combine the specific advantages of each.

Interactions of Bacillus thuringiensis bioinsecticides and the predatory stink bug Podisus nigrispinus to control Plutella xylostella

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparing de novo and reference-based transcriptome assembly strategies by applying them to the blood-sucking bug Rhodnius prolixus

High Throughput Sequencing capabilities have made the process of assembling a transcriptome easier, whether or not there is a reference genome. But the quality of a transcriptome assembly must be good enough to capture the most comprehensive catalog of transcripts and their variations, and to carry out further experiments on transcriptomics. There is currently no consensus on which of the many sequencing technologies and assembly tools are the most effective. Many non-model organisms lack a reference genome to guide the transcriptome assembly. One question, therefore, is whether or not a reference-based genome assembly gives better results than de novo assembly. The blood-sucking insect Rhodnius prolixus-a vector for Chagas disease-has a reference genome. It is therefore a good model on which to compare reference-based and de novo transcriptome assemblies. In this study, we compared de novo and reference-based genome assembly strategies using three datasets (454, Illumina, 454 combined with Illumina) and various assembly software. We developed criteria to compare the resulting assemblies: the size distribution and number of transcripts, the proportion of potentially chimeric transcripts, how complete the assembly was (completeness evaluated both through CEGMA software and R. prolixus proteome fraction retrieved). Moreover, we looked for the presence of two chemosensory gene families (Odorant-Binding Proteins and Chemosensory Proteins) to validate the assembly quality. The reference-based assemblies after genome annotation were clearly better than those generated using de novo strategies alone. Reference-based strategies revealed new transcripts, including new isoforms unpredicted by automatic genome annotation. However, a combination of both de novo and reference-based strategies gave the best result, and allowed us to assemble fragmented transcripts.

Towards biological control strategies for the bronze bug, Thaumastocoris peregrinus, on eucalyptus plantations in South America

The bronze bug is an invasive Australian pest that has reached eucalypt production areas worldwide in <10 years. The fi rst record in South America was in 2005 in Argentina. Collaboration in the region towards a unifi ed strategy for the management of the bronze bug started soon after the dispersal of the pest into Brazil and Uruguay was confi rmed. Here, we present the main achievements of this collaboration in four main topics: 1) biology of the pest, 2) monitoring, 3) biological control, and 4) cooperative networks. Two mass rearing procedures have been implemented in the region with relative success, allowing basic biological studies on the pest. Continuous monitoring in the region for >5 years has provided a reasonable knowledge on seasonal patterns of T. peregrinus. Biological control strategies developed include the use of local natural enemies of T. peregrinus, the development of biopesticides, and the introduction of Cleruchoides noackae, an egg parasitoid of T. peregrinus from Australia. We review the main achievements in each country. Finally, a regional network of institutions, researchers, and students has strengthened in the region, providing a solid background for future collaboration.

Biological control of the bronze bug, Thaumastocoris peregrinus, in eucalyptus plantations in Brazil

The bronze bug Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae) was detected in Brazil in 2008 and infested >180 000 ha of eucalyptus plantations in 2011. The bronze bug can cause a reduction of 10–15% in wood productivity after 2 years of heavy infestation. Although there is not an effective control method known, biological control is the main control strategy studied. An exotic egg parasitoid, Cleruchoides noackae (Hymenoptera: Mymaridae), was imported from Australia in 2012, reared in a laboratory and released in three Brazilian regions. Parasitoids were recovered at release points after 20–30 d. In 2013, preliminary evaluations demonstrated parasitoid establishment in these areas, and the parasitoid was recovered in adjacent areas after 1 year of release. Bioassays confi rmed egg parasitism of 15–20% by C. noackae. Other native natural enemies were studied. We found green lacewing Chrysoperla externa and predatory bugs Supputius cincticeps and Atopozelus opsimus preying on nymphs and/or adults of T. peregrinus. Another promising possibility is entomopathogenic fungi. Commercial formulations of Beauveria bassiana were tested with success in lab and fi eld conditions. Fusarium proliferatum and Paecilomyces cateniannulatus caused mortality of T. peregrinus in natural epizooties. After 5 years of research, it is possible to develop an integrated pest management system (IPM) for eucalyptus plantations based on biocontrol strategy for bronze bug.

Funções de pedotransferência para a curva de resistência do solo à penetração

Funções de pedotransferência são regressões utilizadas para estimar atributos edáficos dependentes a partir de atributos independentes e de fácil determinação. Nesse sentido, são propostas na literatura diversas funções de pedotransferência que visam predizer a resistência do solo à penetração. Objetivou-se, portanto, com este trabalho, desenvolver e comparar a eficiência de cinco funções de pedotransferência para a curva de resistência do solo à penetração, presentes na literatura, por meio do ajuste de dados obtidos tanto com o penetrômetro de impacto (campo) quanto com o penetrômetro eletrônico (laboratório), em um Latossolo manejado sob diferentes modos (convencional e plantio direto). Foram coletadas amostras indeformadas de solo na entrelinha das culturas, nas camadas de 0-0,10, 0,10-0,20 e 0,20-0,30 m, logo após a semeadura, no florescimento e na colheita, para determinação dos atributos físico-hídricos do solo e também da resistência do solo à penetração, com o uso do penetrômetro eletrônico. A resistência do solo à penetração, obtida com o penetrômetro de impacto, foi determinada conforme a variação do conteúdo de água no solo ao longo do ciclo das culturas. As curvas ajustadas de resistência do solo à penetração tiveram a precisão e a acurácia testadas por meio de parâmetros estatísticos e foram comparadas pelo teste F. Houve sobreposição dos valores estimados pelo ajuste das curvas, evidenciando que a maneira de obtenção da resistência do solo à penetração (campo ou laboratório) não influenciou a relação entre a resistência à penetração e os atributos do solo. As equações RP = aUg b; RP = a(1-Ug)b; RP = ae bUg e RP = a + be não diferiram e foram as mais precisas e acuradas na predição da resistência do solo à penetração.

Divergência genética de cultivares de arroz quanto à resistência a Tibraca limbativentris Stål (Hemiptera: Pentatomidae)

A divergência genética de 16 cultivares de arroz quanto à resistência ao percevejo-do-colmo-do-arroz, Tibraca limbativentris Stål, foi avaliada por meio de técnicas de análise multivariada. O experimento foi conduzido em casa de vegetação, em delineamento experimental de blocos ao acaso, com oito repetições. Na avaliação foram considerados oito caracteres de resistência ao ataque do inseto. A divergência genética foi avaliada por procedimentos multivariados: distância generalizada de Mahalanobis (D²), método de agrupamento de otimização de Tocher e técnica de variáveis canônicas. As cultivares mais dissimilares foram Bico Ganga e Marabá Branco, enquanto Agulha e Branco Tardão foram as mais similares. Foram formados cinco grupos pelo método de otimização de Tocher. As três primeiras variáveis canônicas explicaram 88,5% da variabilidade total disponível. Conclui-se que as técnicas de análise multivariada são eficientes para a análise da divergência genética entre as cultivares de arroz, com destaque para Marabá Branco e Bico Ganga, consideradas as mais promissoras a serem utilizadas em futuros cruzamentos para melhoramento visando resistência ao percevejo-do-colmo-do-arroz.

Uso de graus-dia para a previsão de ocorrência de ninfas e adultos de Piezodorus guildinii (West.) (Heteroptera: Pentatomidae) em soja

O presente estudo foi desenvolvido na FCAV-UNESP, em Jaboticabal, SP, durante as safras agrícolas de 1995/96 e 1996/97, visando à previsão de ocorrência de ninfas e adultos de Piezodorus guildinii (West.), por meio de um modelo de graus-dia. As datas em que as primeiras posturas e os primeiros adultos do percevejo foram encontrados na soja foram usadas para dar início à soma acumulada de graus-dia. A previsão de ocorrência foi mais precisa para picos populacionais de adultos do que para diferentes ínstares de P. guildinii.

Efecto Insecticida del Extracto de Semillas de Neem (Azadirachta indica A. Juss) sobre Collaria scenica Stal (Hemiptera: Miridae)

This work was developed with the objetive to evaluate the insecticidal effect of the Neem (Azadirachta indica A. Juss) seeds against grass bug nymphs Collaria scenica Stal. For that, an extract was prepared from green fruits of Neem by rotaevaporacion. The extract was diluted in three ppm concentrations corresponding to treatments. Using thin-layer chromatography we identified the presence of Azaridactina. DCA essay was carried out with 4 treatments and 5 repetitions that included the three extract concentrations and a control. In each repetition were used 15 nymphs, randomly placed in plastic boxes with food and the corresponding concentration. Every day an extract application was made and recorded mortality percentage, number of exuviae and number of individuals who came to adulthood in each treatment. The results were analyzed using Kruskal-Wallis and Games-Howell for each variable. The three concentrations of Neem seed extract had a negative effect on the development of the bugs. The more concentrated treatment (250 ppm) was the most effective, showing a 97% mortality, fewer exuvias and and fewer adults in the end of the experiment.

Biology of Thaumastocoris peregrinus in different eucalyptus species and hybrids

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Occurrence of Atopozelus opsimus preying on nymphs and adults of Glycaspis brimblecombei

The stink bugs genus Atopozelus (Hemiptera: Reduviidae) is native in the Americas, with five described species of which only three have been recorded in Brazil. In August 2007, Eucalyptus camaldulensis leaves infested by lerp psyllid were collected and taken to the Forest Pest Biological Control Laboratory situated at São Paulo State University. A small green stink bug, identified as Atopozelus opsimus Elkins (Hemiptera: Reduviidae) that fed on nymphs and adult psyllids, was found on the leaves. These stink bugs presented phytophagy, omnivory and ability in opening the lerp (shell) that protect the psyllid. A. opsimus has demonstrated unusual particularities, different from many biological control agents found in nature; this predator thus deserves more attention for its potential to be evaluated.

Preferência alimentar e aspectos biológicos de Leptoglossus zonatus Dallas,1852 (Hemiptera: Coreidae) em diferentes genótipos de milho

The present research was accomplished under field and laboratory conditions (T= 25[plus or minus]2[degree] C, R.H.= 70[plus or minus] 10 % and fotoperiod= 12 horas) at FCA/UNICASTELO from Fernandopolis-SP, Brazil. The feeding preference of corn bug Leptoglossus zonatus Dallas, 1852 (Hemiptera: Coreidae) was evaluated on corn genotypes AL-Bianco, AL-Manduri, AL-25 Piratininga, AL-34 e AL-Manduri in the field. Besides, some behavioral factors relative to infestation and oviposition were observed. In laboratory, the nymph's development was evaluated on ears from each corn genotype, aiming to verify the non-preference and/or antibiosis ocurrence. The females of L. zonatus preferred to oviposite on sheats from leaves. Adults and nymphs may occur in whole parts of the plants. The AL-25, AL-34, AL-Manduri and AL-Bandeirante corn genotypes were classified as moderately resistant, expressing non-preference and/or antibiosis against the corn bug. In other way AL-Bianco was the most suscetible to nymphs of the insect.