In the article, the features of the distribution of hemiptera along the width-zonal gradient are considered, which is reflected in the depression - Turan-Uyuk, Central-Tuva and Uvs-nuur, located from ...the north to the south. The ways of adaptation of hemiptera to the arid climate of the Ubs-nuur depression are singled out.
The subgenus Edessa, the largest and to date the most confusing taxon of Edessa is diagnosed here, comprising 79 species listed in this work. The subgenus is characterized by the humeral angles ...conical, somewhat developed, and projected, with apex rounded or somewhat acuminated, but never acute, shyny and impunctate or with a few punctures. The E. sexdens group, composed of 22 species, is proposed here to the subgenus Edessa. This group can be characterized by the anterior arms of the metasternal process with excavated apex; connexival segments with a pair of dark spots; ventral side of the abdomen raised medially; rounded shallow excavation near each spiracle; area between dorsal rim of the pygophore and posterolateral angles grooved; superior process of the genital cup laminar and continued ventrally by a carina, oblique to the parameres; parameres with three lobes; area between dorsal rim of the pygophore and posterolateral angles grooved. The species of the E. sexdens group are distributed in the Neotropical region, from Mexico to Argentina. Descriptions, measurements, and illustrations are provided. An identification key and distributional map are presented. The species Edessa suturata Dallas, 1851 is considered junior synonym of E. alces Erichson, 1848; E. inclyta Walker, 1868, E. fuscidorsata Distant, 1881, and E. gnu Breddin, 1905 are considered junior synonyms of E. electa Walker, 1868; E. olivacea Stål, 1862 and E. ventralis Walker, 1868 are considered junior synonym of E. phoenicopus Dallas, 1851; E. nigromarginata Distant, 1881 is considered junior synonym of E. sexdens Fabricius, 1803; E. subandina Breddin, 1994 is considered a valid species; Edessa dentata (Dallas, 1851) and Edessa excellens (Walker, 1868) are considered junior synonym of E. (E.) urus Erichson, 1848.
Taxon-restricted genes make up a considerable proportion of genomes, yet their contribution to phenotypic evolution is poorly understood. We combined gene expression with functional and behavioral ...assays to study the origin and adaptive value of an evolutionary innovation exclusive to the water strider genus Rhagovelia: the propelling fan. We discovered that two taxon-restricted genes, which we named geisha and mother-of-geisha, specifically control fan development. geisha originated through a duplication event at the base of the Rhagovelia lineage, and both duplicates acquired a novel expression in a specific cell population prefiguring fan development. These gene duplicates played a central role in Rhagovelia’s adaptation to a new physical environment, demonstrating that the evolution of taxon-restricted genes can contribute directly to evolutionary novelties that allow access to unexploited ecological niches.
Evolutionary adaptations for the exploitation of nutritionally challenging or toxic host plants represent a major force driving the diversification of phytophagous insects. Although symbiotic ...bacteria are known to have essential nutritional roles for insects, examples of radiations into novel ecological niches following the acquisition of specific symbionts remain scarce. Here we characterized the microbiota across bugs of the family Pyrrhocoridae and investigated whether the acquisition of vitamin-supplementing symbionts enabled the hosts to diversify into the nutritionally imbalanced and chemically well-defended seeds of Malvales plants as a food source. Our results indicate that vitamin-provisioning Actinobacteria (Coriobacterium and Gordonibacter), as well as Firmicutes (Clostridium) and Proteobacteria (Klebsiella) are widespread across Pyrrhocoridae, but absent from the sister family Largidae and other outgroup taxa. Despite the consistent association with a specific microbiota, the Pyrrhocoridae phylogeny is neither congruent with a dendrogram based on the hosts' microbial community profiles nor phylogenies of individual symbiont strains, indicating frequent horizontal exchange of symbiotic partners. Phylogenetic dating analyses based on the fossil record reveal an origin of the Pyrrhocoridae core microbiota in the late Cretaceous (81.2-86.5 million years ago), following the transition from crypt-associated beta-proteobacterial symbionts to an anaerobic community localized in the M3 region of the midgut. The change in symbiotic syndromes (that is, symbiont identity and localization) and the acquisition of the pyrrhocorid core microbiota followed the evolution of their preferred host plants (Malvales), suggesting that the symbionts facilitated their hosts' adaptation to this imbalanced nutritional resource and enabled the subsequent diversification in a competition-poor ecological niche.
Symbiont-mediated insecticide resistance Kikuchi, Yoshitomo; Hayatsu, Masahito; Hosokawa, Takahiro ...
Proceedings of the National Academy of Sciences,
05/2012, Letnik:
109, Številka:
22
Journal Article
Recenzirano
Odprti dostop
Development of insecticide resistance has been a serious concern worldwide, whose mechanisms have been attributed to evolutionary changes in pest insect genomes such as alteration of drug target ...sites, up-regulation of degrading enzymes, and enhancement of drug excretion. Here, we report a previously unknown mechanism of insecticide resistance: Infection with an insecticide-degrading bacterial symbiont immediately establishes insecticide resistance in pest insects. The bean bug Riptortus pedestris and allied stinkbugs harbor mutualistic gut symbiotic bacteria of the genus Burkholderia, which are acquired by nymphal insects from environmental soil every generation. In agricultural fields, fenitrothion-degrading Burkolderia strains are present at very low densities. We demonstrated that the fenitrothion-degrading Burkholderia strains establish a specific and beneficial symbiosis with the stinkbugs and confer a resistance of the host insects against fenitrothion. Experimental applications of fenitrothion to field soils drastically enriched fenitrothion-degrading bacteria from undetectable levels to >80% of total culturable bacterial counts in the field soils, and >90% of stinkbugs reared with the enriched soil established symbiosis with fenitrothion-degrading BURKHOLDERIA: In a Japanese island where fenitrothion has been constantly applied to sugarcane fields, we identified a stinkbug population wherein the insects live on sugarcane and ≈8% of them host fenitrothion-degrading BURKHOLDERIA: Our finding suggests the possibility that the symbiont-mediated insecticide resistance may develop even in the absence of pest insects, quickly establish within a single insect generation, and potentially move around horizontally between different pest insects and other organisms.
Global warming impacts diverse organisms not only directly but also indirectly via other organisms with which they interact. Recently, the possibility that elevated temperatures resulting from global ...warming may substantially affect biodiversity through disrupting mutualistic/parasitic associations has been highlighted. Here we report an experimental demonstration that global warming can affect a pest insect via suppression of its obligate bacterial symbiont. The southern green stinkbug Nezara viridula depends on a specific gut bacterium for its normal growth and survival. When the insects were reared inside or outside a simulated warming incubator wherein temperature was controlled at 2.5°C higher than outside, the insects reared in the incubator exhibited severe fitness defects (i.e., retarded growth, reduced size, yellowish body color, etc.) and significant reduction of symbiont population, particularly in the midsummer season, whereas the insects reared outside did not. Rearing at 30°C or 32.5°C resulted in similar defective phenotypes of the insects, whereas no adult insects emerged at 35°C. Notably, experimental symbiont suppression by an antibiotic treatment also induced similar defective phenotypes of the insects, indicating that the host's defective phenotypes are attributable not to the heat stress itself but to the suppression of the symbiont population induced by elevated temperature. These results strongly suggest that high temperature in the midsummer season negatively affects the insects not directly but indirectly via the heat-vulnerable obligate bacterial symbiont, which highlights the practical relevance of mutualism collapse in this warming world.
Climate change is among the biggest environmental issues in the contemporary world, and its impact on the biodiversity and ecosystem is not only of scientific interest but also of practical concern for the general public. On the basis of our laboratory data obtained under strictly controlled environmental conditions and our simulated warming data obtained in seminatural settings (elevated 2.5°C above the normal temperature), we demonstrate here that Nezara viridula, the notorious stinkbug pest, suffers serious fitness defects in the summer season under the simulated warming conditions, wherein high temperature acts on the insect not directly but indirectly via suppression of its obligate gut bacterium. Our finding highlights that heat-susceptible symbionts can be the "Achilles' heel" of symbiont-dependent organisms under climate change conditions.
Despite the demonstrated functional importance of gut microbes, our understanding of how animals regulate their metabolism in response to nutritionally beneficial symbionts remains limited. Here, we ...elucidate the functional importance of the African cotton stainer's (Dysdercus fasciatus) association with two actinobacterial gut symbionts and subsequently examine the insect's transcriptional response following symbiont elimination. In line with bioassays demonstrating the symbionts' contribution towards host fitness through the supplementation of B vitamins, comparative transcriptomic analyses of genes involved in import and processing of B vitamins revealed an upregulation of gene expression in aposymbiotic (symbiont-free) compared with symbiotic individuals; an expression pattern that is indicative of B vitamin deficiency in animals. Normal expression levels of these genes, however, can be restored by either artificial supplementation of B vitamins into the insect's diet or reinfection with the actinobacterial symbionts. Furthermore, the functional characterization of the differentially expressed thiamine transporter 2 through heterologous expression in Xenopus laevis oocytes confirms its role in cellular uptake of vitamin B1. These findings demonstrate that despite an extracellular localization, beneficial gut microbes can be integral to the host's metabolic homeostasis, reminiscent of bacteriome-localized intracellular mutualists.
Hemiptera, the largest non-holometabolous order of insects, represents approximately 7% of metazoan diversity. With extraordinary life histories and highly specialized morphological adaptations, ...hemipterans have exploited diverse habitats and food sources through approximately 300 Myr of evolution. To elucidate the phylogeny and evolutionary history of Hemiptera, we carried out the most comprehensive mitogenomics analysis on the richest taxon sampling to date covering all the suborders and infraorders, including 34 newly sequenced and 94 published mitogenomes. With optimized branch length and sequence heterogeneity, Bayesian analyses using a site-heterogeneous mixture model resolved the higher-level hemipteran phylogeny as (Sternorrhyncha, (Auchenorrhyncha, (Coleorrhyncha, Heteroptera))). Ancestral character state reconstruction and divergence time estimation suggest that the success of true bugs (Heteroptera) is probably due to angiosperm coevolution, but key adaptive innovations (e.g. prognathous mouthpart, predatory behaviour, and haemelytron) facilitated multiple independent shifts among diverse feeding habits and multiple independent colonizations of aquatic habitats.
Leaffooted plant bugs (LFPBs) (Leptoglossus spp., Guérin-Méneville) (Hemiptera: Coreidae) are large seed-feeding bugs native to the Western Hemisphere. In California, several Leptoglossus spp. feed ...on almonds, pistachios, and pomegranate and are occasional pests.The objective of this study was to survey the different species of Leptoglossus present in almond, pistachio, and pomegranate orchards in the Central Valley of California. We used two molecular markers, amplified fragment length polymorphisms (AFLPs) and mitochondrial DNA COI, to determine the number of species or strains of each species, and to infer whether individuals of each species move and possibly interbreed with populations from the other host plants. Two species of leaffooted bugs were abundant, Leptoglossus clypealis Heidemann, and Leptoglossus zonatus (Dallas). L. clypealis was collected in almond and pistachio, while L. zonatus was found on all three host plants, but was the dominant species in pomegranate. The AFLP results indicated that L. clypealis consisted of one species, which suggests it moves between almonds and pistachios during the growing season. Mitochondrial DNA COI for L. clypealis found 1–2% divergence between sequences, and a high haplotype diversity of 0.979 with 17 haplotypes. The AFLP results for L. zonatus found two genetically divergent populations which were morphologically similar. The mtDNA COI sequences for L. zonatus were used for haplotype analysis; three haplotypes were found in California, with one haplotype shared with collections from Brazil. The importance of genetic variability and cryptic species for pest management are discussed.
A number of insects establish symbiotic associations with beneficial microorganisms in various manners. The bean bug Riptortus pedestris and allied stink bugs possess an environmentally acquired ...Burkholderia symbiont in their midgut crypts. Unlike other insect endosymbionts, the Burkholderia symbiont is easily culturable and genetically manipulatable outside the host. In conjunction with the experimental advantages of the host insect, the Riptortus–Burkholderia symbiosis is an ideal model system for elucidating the molecular bases underpinning insect-microbe symbioses, which opens a new window in the research field of insect symbiosis. This review summarizes current knowledge of this system and discusses future perspectives.
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