Pest categorisation of Crisicoccus seruratus.

Following the commodity risk assessments of Acer palmatum plants grafted on A. davidii from China, in which Crisicoccus matsumotoi (Hemiptera: Pseudococcidae) was identified as a pest of possible concern, the European Commission requested the EFSA Panel on Plant Health to conduct a pest categorisation of C. matsumotoi for the territory of the European Union. Recent taxonomic revision of the genus Crisisoccus concluded that C. matsumotoi is a synonym of C. seruratus; therefore, the categorisation will use the current valid name C. seruratus. It is an insect pest native to Japan, feeding on species in 13 plant families. There are reports of its presence also in China and the Republic of Korea, but there is great uncertainty about the identity of the species for these records. Therefore, there is uncertainty about the species referred to as C. matsumotoi in the commodity risk assessments of A. palmatum. C. seruratus is a multivoltine species. It has three generations per year and overwinters as a nymph. The most important crops that may be affected by C. seruratus are figs (Ficus carica), grapes (Vitis spp.), nashi pears (Pyrus pyrifolia var. culta), persimmons (Diospyros kaki) and walnuts (Juglans regia). Plants for planting and fruits provide potential pathways for entry into the EU. Host availability and climate suitability suggest that the central, northern and some areas of southern EU countries would be suitable for the establishment of C. seruratus. The introduction of this mealybug would likely have an economic impact in the EU through yield reduction and fruit downgrading because of honeydew deposition and the consequent growth of sooty moulds. This insect is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. Phytosanitary measures are available to reduce the likelihood of entry and spread of this species into the EU. C. seruratus satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

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))).

Prevalence in Potato of 'Candidatus Arsenophonus Phytopathogenicus' and 'Candidatus Phytoplasma Solani' and Their Transmission via Adult Pentastiridius leporinus.

The planthopper Pentastiridius leporinus (Hempiptera: Cixiidae) is the main vector of two bacterial pathogens: the γ-proteobacterium 'Candidatus Arsenophonus phytopathogenicus' and the stolbur phytoplasma 'Candidatus Phytoplasma solani'. These pathogens cause the disease syndrome basses richesses (SBR) in sugar beet (Beta vulgaris), which reduces the yields and sugar content. In 2022, potato (Solanum tuberosum) fields were found to be colonized by P. leporinus, and the transmission of Arsenophonus was confirmed, resulting in symptoms like wilting, yellow leaves, and rubbery tubers. We monitored both pathogens in Southwest Germany in 2022 and 2023. This revealed their widespread presence in potato tubers, although there were differences in regional prevalence. The broad prevalence of Arsenophonus was maintained in 2023, whereas the prevalence of stolbur increased in most locations. We confirmed that P. leporinus adults can transmit both pathogens to potatoes, but neither pathogen reduced the germination rate of tubers, and no plants showed abnormal growth after germination. Arsenophonus was not detected in germinated shoots, but 5.4% contained stolbur, emphasizing the need for plant material testing to maintain phytosanitary conditions.

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.

Pest categorisation of Eulecanium giganteum.

The EFSA Panel on Plant Health performed a pest categorisation of Eulecanium giganteum (Hemiptera: Coccidae), the giant eulecanium scale, for the territory of the European Union, following the commodity risk assessment of Acer palmatum plants from China, in which E. giganteum came to attention as a pest of possible concern. The pest is only known to be present in Asia, where it has been reported from China, India, Iran, Japan and eastern Russia (Primorsky Krai). The pest has not been reported within the EU. It is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. It is polyphagous, feeding on broad-leaf trees and shrubs assigned to 41 genera in 22 plant families. Host plant species commonly found in the EU include apricot (Prunus armeniaca), elm (Ulmus spp.), grapevine (Vitis vinifera), maple (Acer spp.), oak (Quercus spp.), oriental plane (Platanus orientalis), pomegranate (Punica granatum), quince (Cydonia oblonga), silkworm mulberry (Morus alba), walnut (Juglans regia), and several ornamentals. Climatic conditions and availability of host plants in southern EU countries would most probably allow this species to successfully establish and spread. However, EU native natural enemies are anticipated to provide biological control and therefore reduce potential impacts. Phytosanitary measures are available to reduce the likelihood of entry and spread. E. giganteum satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest, other than the criterion on impact which is a key uncertainty.

Three new species of the leafhopper genus Arboridia Zachvatkin (Hemiptera, Cicadellidae, Typhlocybinae), with a key and checklist to known species of China.

Three new species of the leafhopper genus ArboridiaZachvatkin 1946, Arboridia (Arboridia) furcata Han, sp. nov., Arboridia (Arboridia) rubrovittata Han, sp. nov., and Arboridia (Arboridia) robustipenis Han, sp. nov., are described and illustrated from fruit trees in Southwest China. A key and checklist to known species from China are provided.

Histological Observation of Helmet Development in the Treehopper Poppea capricornis (Insecta: Hemiptera: Membracidae).

The treehoppers (Hemiptera, Membracidae) are known for possessing a large three-dimensional structure called a helmet. Although some ecological functions of the helmet have already been elucidated, the developmental mechanisms underlying the complex and diverse morphology of the helmet are still largely unknown. The process of helmet formation was first described in Antianthe expansa, which possesses a simple roof-shaped helmet. However, the developmental process in species with more complex helmet morphologies remains largely unexplored. Hence, in this study, we used Poppea capricornis, which possesses a more complex helmet structure than A. expansa, to investigate the helmet development using paraffin sections, micro-CT, and scanning electronic microscopy. Our focus was on the overall helmet developmental process common to both species and formation of structures unique to Poppea and its comparison to Antianthe. As a result, we discovered that miniature structures were also formed in Poppea, similar to Antianthe, during the helmet formation. Common structures that were shared between the two species were discernible at this stage. Additionally, we observed that suprahumeral horns and posterior horns, two morphological traits specific to the Poppea helmet that are apparently similar anatomically, are formed through two distinctly different developmental mechanisms. The suprahumeral horns appeared to be formed by utilizing the nymphal suprahumeral bud as a mold, while we could not detect any nymphal structures potentially used for a mold in the posterior horns formation. Our findings suggest that the helmet formation mechanisms of Antianthe and Poppea employ a common mechanism but form species-specific structures by multiple mechanisms.

A pooled-sample draft genome assembly provides insights into host plant-specific transcriptional responses of a Solanaceae-specializing pest, Tupiocoris notatus (Hemiptera: Miridae).

The assembly of genomes from pooled samples of genetically heterogenous samples of conspecifics remains challenging. In this study, we show that high-quality genome assemblies can be produced from samples of multiple wild-caught individuals. We sequenced DNA extracted from a pooled sample of conspecific herbivorous insects (Hemiptera: Miridae: Tupiocoris notatus) acquired from a greenhouse infestation in Tucson, Arizona (in the range of 30-100 individuals; 0.5 mL tissue by volume) using PacBio highly accurate long reads (HiFi). The initial assembly contained multiple haplotigs (>85% BUSCOs duplicated), but duplicate contigs could be easily purged to reveal a highly complete assembly (95.6% BUSCO, 4.4% duplicated) that is highly contiguous by short-read assembly standards (N 50 = 675 kb; Largest contig = 4.3 Mb). We then used our assembly as the basis for a genome-guided differential expression study of host plant-specific transcriptional responses. We found thousands of genes (N = 4982) to be differentially expressed between our new data from individuals feeding on Datura wrightii (Solanaceae) and existing RNA-seq data from Nicotiana attenuata (Solanaceae)-fed individuals. We identified many of these genes as previously documented detoxification genes such as glutathione-S-transferases, cytochrome P450s, and UDP-glucosyltransferases. Together our results show that long-read sequencing of pooled samples can provide a cost-effective genome assembly option for small insects and can provide insights into the genetic mechanisms underlying interactions between plants and herbivorous pests.

Pest categorisation of Lepidosaphes malicola.

The EFSA Panel on Plant Health performed a pest categorisation of Lepidosaphes malicola (Hemiptera: Diaspididae), the Armenian mussel scale, for the territory of the European Union, following commodity risk assessments of Prunus persica and P. dulcis plants for planting from Türkiye, in which L. malicola was identified as a pest of possible concern. L. malicola is a polyphagous insect of temperate and arid areas, feeding on more than 60 plant species belonging to 26 families. Important crops significantly affected by L. malicola in parts of Asia include stone fruits (Prunus armeniaca, P. persica), pome fruits (Malus domestica, Pyrus communis), grapes (Vitis vinifera), pomegranate (Punica granatum), walnuts (Juglans regia) and ornamental plants (Berberis spp., Cornus spp., Jasminum spp., Ligustrum spp.). L. malicola has two generations annually. The overwintered eggs hatch from late May to early June. First-instar nymphs crawl on the host plant for a short period, then settle to feed. Nymphs reach maturity in late summer or early autumn. Plants for planting, fruits and cut flowers provide potential pathways for entry into the EU. Host availability and climate suitability suggest that southern, central and some parts of northern EU countries would be suitable for the establishment of L. malicola. Despite being a pest in Armenia, Iran and Tajikistan, there is no evidence of it being a pest in Türkiye. L. malicola was detected in Bulgaria and Greece over 30 years ago, but there have been no records since, and its status is uncertain. Its ability to cause an impact in the EU is also uncertain. It is not listed in Annex II of the Commission Implementing Regulation (EU) 2019/2072. Phytosanitary measures are available to reduce the likelihood of entry. Except for the criterion of having an economic or environmental impact, for which there is great uncertainty, L. malicola satisfies all other criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

The first A-to-I RNA editome of hemipteran species Coridius chinensis reveals overrepresented recoding and prevalent intron editing in early-diverging insects.

BACKGROUND: Metazoan adenosine-to-inosine (A-to-I) RNA editing resembles A-to-G mutation and increases proteomic diversity in a temporal-spatial manner, allowing organisms adapting to changeable environment. The RNA editomes in many major animal clades remain unexplored, hampering the understanding on the evolution and adaptation of this essential post-transcriptional modification. METHODS: We assembled the chromosome-level genome of Coridius chinensis belonging to Hemiptera, the fifth largest insect order where RNA editing has not been studied yet. We generated ten head RNA-Seq libraries with DNA-Seq from the matched individuals. RESULTS: We identified thousands of high-confidence RNA editing sites in C. chinensis. Overrepresentation of nonsynonymous editing was observed, but conserved recoding across different orders was very rare. Under cold stress, the global editing efficiency was down-regulated and the general transcriptional processes were shut down. Nevertheless, we found an interesting site with "conserved editing but non-conserved recoding" in potassium channel Shab which was significantly up-regulated in cold, serving as a candidate functional site in response to temperature stress. CONCLUSIONS: RNA editing in C. chinensis largely recodes the proteome. The first RNA editome in Hemiptera indicates independent origin of beneficial recoding during insect evolution, which advances our understanding on the evolution, conservation, and adaptation of RNA editing.

Taxonomy and Phylogeny of the Aphid Genus Nippolachnus Matsumura, 1917, with Synonymy of the Mysterious Neonippolachnus Shinji, 1924 (Hemiptera: Aphididae: Lachninae).

Nippolachnus Matsumura, 1917 is a small aphid genus from the tribe Tuberolachnini (Hemiptera: Lachninae) occurring in Southeast Asia. Species from this genus are quite characteristic and stand out among lachnids for their morphology and ecological associations. We have performed a revision and phylogenetic analyses to elucidate the relationships within Nippolachnus and other representatives of Tuberolachnini. Here, the taxonomy of the genus is revised based on morphological data to include seven species, three of them newly described: Nippolachnus chakrabartiisp. nov. from India, Nippolachnus sinensissp. nov. from China, and Nippolachnus malayaensissp. nov. from Indonesia. Nippolachnus appear to be non monophyletic genus and a new genus, Indolachnusgen. nov., is described to accommodate Nippolachnus himalayensis (van der Goot, 1917) as Indolachnus himalayensis (van der Goot, 1917) comb. nov. The new genus is a sister group to the remaining Nippolachnus species, which created a monophyletic clade. Neonippolachnus Shinji, 1924 syn. nov. is recognised as a synonym of Nippolachnus, and Neonippolachnus betulae Shinji, 1924 syn. nov. as a synonym of Nippolachnus micromeli Shinji, 1924. For the first time, a scanning electron microscopy study of the sexual generation of N. piri Matsumura, 1917 has been performed. Apterous and alate viviparous females of N. bengalensis Basu and Hille Ris Lambers, 1968, N. piri, and N. micromeli, and alate viviparous females of N. xitianmushanus Zhang and Zhong, 1982 are re-described and illustrated, as well as apterous and alate viviparous females of I. himalayensiscomb. nov. Hitherto unknown morphs of N. micromeli, N. piri, and N. xitianmushanus are described. A lectotype and paralectotypes of N. xitianmushanus are designated herein. Notes on distribution and host plants are given, and keys to apterous and alate viviparous females of the genera Nippolachnus and Indolachnus are also provided.

Host plant preference of Lygus hesperus (Hemiptera: Miridae) in 4 field crops: potato, alfalfa, carrot, and pea.

The western tarnished plant bug, Lygus hesperus (Knight), has emerged as a pest of potatoes (Solanum tuberosum L.) in the Lower Columbia Basin of Oregon and Washington. This species is generally found infesting several other field-grown crops in the region; however, their host preference is poorly understood. Thus, greenhouse cage experiments were conducted to evaluate L. hesperus host preference by simultaneously presenting adults with 4 host plants: potato, alfalfa, Medicago sativa L., carrot, Daucus carota L., and pea, Pisum sativum L. In addition, an oviposition test was conducted. The results indicated that L. hesperus actively chose as a host and as an oviposition substrate among the 4 host plants. We found a significantly higher number of adults on alfalfa and potato plants over carrot or pea plants at 6 h, 24 h, and 48 h after adults were released into the cage. However, 96 h after release, more L. hesperus were found in alfalfa. In addition, female L. hesperus strongly preferred potato and alfalfa plants as an oviposition substrate over carrot and pea plants at 96 h after release.

Morphology of the male reproductive system and sperm of Leptoglossus zonatus (Dallas, 1852) (Heteroptera: Coreidae).

Taxonomic data on Coreidae have been fragmented over time and need to be revised. Likewise, data related to the development of germ cells and the features of the male reproductive system, including sperm, will contribute to understanding the biological mechanisms of reproduction and the systematics of its representatives. Aiming to provide these data, we describe the morphology of the male reproductive system and spermatozoa of Leptoglossus zonatus using light and transmission electron microscopies, respectively. Each of the two testes is surrounded by a bright red-pigmented sheath and formed by seven follicles arranged side by side. The two vasa deferentia are filled with individualized sperm, especially in their final portion, which is dilated and curved. After dilation, the vasa deferentia receive the ducts of the accessory glands of mesodermal origin. The other unpaired accessory gland is of ectodermal origin and opens into the ejaculatory duct. Both glandular types are densely coiled and have lumens filled with secreted material. Testicular follicles contain cysts with germ cells at different stages of spermatogenesis, indicating continuous production of gametes throughout adult life. Mature sperm measure around 310 µm long, with a nucleus of 36 µm and a flagellum formed only by an axoneme of 9 + 9 + 2 microtubules and two symmetrical mitochondrial derivatives. Like the sperm of other Heteroptera, the acrosome has a single structure (without perforatorium), there are no accessory bodies in the flagella, and the mitochondrial derivatives are connected to the axonemes, supporting the synapomorphic condition of these characteristics for this suborder of bedbugs. RESEARCH HIGHLIGHTS: The Leptoglossus zonatus sperm are slender and long, about 310 µm in length, and a nucleus 36 µm long. Spermatogenesis occurs throughout adult life and equally in the seven testicular follicles. The centriole adjunct in L. zonatus sperm does not give rise to accessory bodies. The ectodermal gland produces a filamentous secretion, whereas in the ectodermal sac, the secretion is globular.

The Genome of Arsenophonus sp. and Its Potential Contribution in the Corn Planthopper, Peregrinus maidis.

The co-evolution between symbionts and their insect hosts has led to intricate functional interdependencies. Advances in DNA-sequencing technologies have not only reduced the cost of sequencing but, with the advent of highly accurate long-read methods, have also enabled facile genome assembly even using mixed genomic input, thereby allowing us to more easily assess the contribution of symbionts to their insect hosts. In this study, genomic data recently generated from Peregrinus maidis was used to assemble the genome of a bacterial symbiont, Pm Arsenophonus sp. This ~4.9-Mb assembly is one of the largest Arsenophonus genomes reported to date. The Benchmarking Universal Single-Copy Orthologs (BUSCO) result indicates that this Pm Arsenophonus assembly has a high degree of completeness, with 96% of the single-copy Enterobacterales orthologs found. The identity of the Pm Arsenophonus sp. was further confirmed by phylogenetic analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicates a major contribution by Pm Arsenophonus sp. to the biosynthesis of B vitamins and essential amino acids in P. maidis, where threonine and lysine production is carried out solely by Pm Arsenophonus sp. This study not only provides deeper insights into the evolutionary relationships between symbionts and their insect hosts, but also adds to our understanding of insect biology, potentially guiding the development of novel pest control methods.

Chromosome-Level Genome Assembly and Annotation of a Periodical Cicada Species: Magicicada septendecula.

We present a high-quality assembly and annotation of the periodical cicada species, Magicicada septendecula (Hemiptera: Auchenorrhyncha: Cicadidae). Periodical cicadas have a significant ecological impact, serving as a food source for many mammals, reptiles, and birds. Magicicada are well known for their massive emergences of 1 to 3 species that appear in different locations in the eastern United States nearly every year. These year classes ("broods") emerge dependably every 13 or 17 yr in a given location. Recently, it has become clear that 4-yr early or late emergences of a sizeable portion of a population are an important part of the history of brood formation; however, the biological mechanisms by which they track the passage of time remain a mystery. Using PacBio HiFi reads in conjunction with Hi-C proximity ligation data, we have assembled and annotated the first whole genome for a periodical cicada, an important resource for future phylogenetic and comparative genomic analysis. This also represents the first quality genome assembly and annotation for the Hemipteran superfamily Cicadoidea. With a scaffold N50 of 518.9 Mb and a complete BUSCO score of 96.7%, we are confident that this assembly will serve as a vital resource toward uncovering the genomic basis of periodical cicadas' long, synchronized life cycles and will provide a robust framework for further investigations into these insects.

The evolving story of sulfoxaflor resistance in the green peach aphid, Myzus persicae (Sulzer).

BACKGROUND: The green peach aphid, Myzus persicae (Sulzer), is one of the most economically important crop pests worldwide. Insecticide resistance in this pest was first detected over 60 years ago, with resistance in M. persicae now spanning over 80 active ingredients. Sulfoxaflor is a relatively new insecticide that is primarily used to control sap-feeding insects. In 2018 resistance to sulfoxaflor was discovered in field populations of M. persicae in Australia. This study aimed to determine the current distribution and phenotypic levels of sulfoxaflor resistance in Australian clones of M. persicae and to investigate how these patterns relate to clonal type. RESULTS: For the first time, we show there is low-level resistance (8-26-fold) distributed across Australia, with resistance being detected in aphids collected from approximately 20% of all M. persicae collected and screened. Furthermore, this study shows sulfoxaflor resistance is found in two M. persicae haplotypes, providing evidence that there have been multiple independent evolutionary events which have given rise to sulfoxaflor resistance in this species. CONCLUSION: These findings have important implications for the chemical control of M. persicae in Australia, especially when considering the broader genetic background of these aphids which are known to harbour a number of other insecticide resistance mechanisms. We recommend continuous monitoring of sulfoxaflor resistance in field populations of M. persicae (in Australia and elsewhere) and further research into the underlying genetic mechanisms conferring resistance to sulfoxaflor in both clonal haplotypes. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Sucking insects and their predators on tree canopies of a monocultural stand of Caryocar brasiliense

Abstract Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae) trees are widely distributed throughout the Cerrado ecosystem. The fruits of C. brasiliense trees are used by humans for food and as the main income source in many communities. C. brasiliense conservation is seriously threatened due to habitat loss caused by the land-use change. Sucking insects constitute an important ecological driver that potentially impact C. brasiliense survival in degraded environments. In addition, insects sampling methodologies for application in studies related to the conservation of C. brasiliense are poorly developed. In this study, sucking insects (Hemiptera) and their predators were recorded in three vertical strata of Caryocar brasiliense canopies. The distribution of sucking species showed vertical stratification along the canopy structure of C. brasiliense. The basal part of the canopy had the highest numbers of sucking insects Aphis gossypii (Glover 1877) (Hemiptera: Aphididae) and Bemisia tabaci (Genn. 1889) (Hemiptera: Aleyrodidae), and their predators Chrysoperla sp. (Neuroptera: Chrysopidae), spiders (Araneae), and Zelus armillatus (Lep. & Servi., 1825) (Hemiptera: Reduviidae). Predators' distribution follows the resource availability and preferred C. brasiliense tree parts with a higher abundance of prey.

Resumo Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae) é amplamente distribuído por todo o ecossistema de cerrado. Os frutos de C. brasiliense são utilizados na alimentação humana e constitui uma importante fonte de renda para muitas comunidades. A perda de habitat provocada pelas mudanças de uso da terra coloca em risco a conservação de C. brasiliense. Insetos sugadores constituem um importante fator ecológico que, potencialmente, afeta o fitness de C. brasiliense em ambientes degradados. Além disso, as metodologias de amostragem de insetos para aplicação em estudos relacionados à conservação de C. brasiliense são pouco desenvolvidas. Neste estudo, o número de insetos sugadores (Hemiptera) e seus predadores foram avaliados em três estratos verticais do dossel de C. brasiliense. A distribuição das espécies sugadoras apresentou estratificação vertical ao longo da estrutura do dossel. O estrato basal do dossel apresentou o maior número de insetos sugadores Aphis gossypii (Glover 1877) (Hemiptera: Aphididae) e Bemisia tabaci (Genn. 1889) (Hemiptera: Aleyrodidae), e seus predadores Chrysoperla sp. (Neuroptera: Chrysopidae), aranhas (Araneae) e Zelus armillatus (Lep. & Servi., 1825) (Hemiptera: Reduviidae). Os predadores distribuíram-se de acordo com a disponibilidade de recursos, ocorrendo em maior número nas partes do dossel com maior abundância de suas presas.

Sucking insects and their predators on tree canopies of a monocultural stand of Caryocar brasiliense / Insetos sugadores e seus predadores na copa de Caryocar brasiliense em sistema de monocultura

Abstract Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae) trees are widely distributed throughout the Cerrado ecosystem. The fruits of C. brasiliense trees are used by humans for food and as the main income source in many communities. C. brasiliense conservation is seriously threatened due to habitat loss caused by the land-use change. Sucking insects constitute an important ecological driver that potentially impact C. brasiliense survival in degraded environments. In addition, insects sampling methodologies for application in studies related to the conservation of C. brasiliense are poorly developed. In this study, sucking insects (Hemiptera) and their predators were recorded in three vertical strata of Caryocar brasiliense canopies. The distribution of sucking species showed vertical stratification along the canopy structure of C. brasiliense. The basal part of the canopy had the highest numbers of sucking insects Aphis gossypii (Glover 1877) (Hemiptera: Aphididae) and Bemisia tabaci (Genn. 1889) (Hemiptera: Aleyrodidae), and their predators Chrysoperla sp. (Neuroptera: Chrysopidae), spiders (Araneae), and Zelus armillatus (Lep. & Servi., 1825) (Hemiptera: Reduviidae). Predators' distribution follows the resource availability and preferred C. brasiliense tree parts with a higher abundance of prey.

Resumo Caryocar brasiliense Camb. (Malpighiales: Caryocaraceae) é amplamente distribuído por todo o ecossistema de cerrado. Os frutos de C. brasiliense são utilizados na alimentação humana e constitui uma importante fonte de renda para muitas comunidades. A perda de habitat provocada pelas mudanças de uso da terra coloca em risco a conservação de C. brasiliense. Insetos sugadores constituem um importante fator ecológico que, potencialmente, afeta o fitness de C. brasiliense em ambientes degradados. Além disso, as metodologias de amostragem de insetos para aplicação em estudos relacionados à conservação de C. brasiliense são pouco desenvolvidas. Neste estudo, o número de insetos sugadores (Hemiptera) e seus predadores foram avaliados em três estratos verticais do dossel de C. brasiliense. A distribuição das espécies sugadoras apresentou estratificação vertical ao longo da estrutura do dossel. O estrato basal do dossel apresentou o maior número de insetos sugadores Aphis gossypii (Glover 1877) (Hemiptera: Aphididae) e Bemisia tabaci (Genn. 1889) (Hemiptera: Aleyrodidae), e seus predadores Chrysoperla sp. (Neuroptera: Chrysopidae), aranhas (Araneae) e Zelus armillatus (Lep. & Servi., 1825) (Hemiptera: Reduviidae). Os predadores distribuíram-se de acordo com a disponibilidade de recursos, ocorrendo em maior número nas partes do dossel com maior abundância de suas presas.

Integrative transcriptomics reveals association of abscisic acid and lignin pathways with cassava whitefly resistance.

BACKGROUND: Whiteflies are a global threat to crop yields, including the African subsistence crop cassava (Manihot esculenta). Outbreaks of superabundant whitefly populations throughout Eastern and Central Africa in recent years have dramatically increased the pressures of whitefly feeding and virus transmission on cassava. Whitefly-transmitted viral diseases threaten the food security of hundreds of millions of African farmers, highlighting the need for developing and deploying whitefly-resistant cassava. However, plant resistance to whiteflies remains largely poorly characterized at the genetic and molecular levels. Knowledge of cassava-defense programs also remains incomplete, limiting characterization of whitefly-resistance mechanisms. To better understand the genetic basis of whitefly resistance in cassava, we define the defense hormone- and Aleurotrachelus socialis (whitefly)-responsive transcriptome of whitefly-susceptible (COL2246) and whitefly-resistant (ECU72) cassava using RNA-seq. For broader comparison, hormone-responsive transcriptomes of Arabidopsis thaliana were also generated. RESULTS: Whitefly infestation, salicylic acid (SA), jasmonic acid (JA), ethylene (ET), and abscisic acid (ABA) transcriptome responses of ECU72 and COL2246 were defined and analyzed. Strikingly, SA responses were largely reciprocal between the two cassava genotypes and we suggest candidate regulators. While susceptibility was associated with SA in COL2246, resistance to whitefly in ECU72 was associated with ABA, with SA-ABA antagonism observed. This was evidenced by expression of genes within the SA and ABA pathways and hormone levels during A. socialis infestation. Gene-enrichment analyses of whitefly- and hormone-responsive genes suggest the importance of fast-acting cell wall defenses (e.g., elicitor recognition, lignin biosynthesis) during early infestation stages in whitefly-resistant ECU72. A surge of ineffective immune and SA responses characterized the whitefly-susceptible COL2246's response to late-stage nymphs. Lastly, in comparison with the model plant Arabidopsis, cassava's hormone-responsive genes showed striking divergence in expression. CONCLUSIONS: This study provides the first characterization of cassava's global transcriptome responses to whitefly infestation and defense hormone treatment. Our analyses of ECU72 and COL2246 uncovered possible whitefly resistance/susceptibility mechanisms in cassava. Comparative analysis of cassava and Arabidopsis demonstrated that defense programs in Arabidopsis may not always mirror those in crop species. More broadly, our hormone-responsive transcriptomes will also provide a baseline for the cassava community to better understand global responses to other yield-limiting pests/pathogens.