Seasonal occurrence of spotted wing drosophila in various small fruits and berries in Pennsylvania and Maryland

Spotted wing drosophila (SWD) (Drosophila suzukii), a major invasive pest of small fruit crops, was first found in Pennsylvania and Maryland during the 2011 crop season, and since then, it has been established throughout the fruit growing regions of both states. A season‐long field study was conducted to find out the seasonal occurrence of SWD in several fruit crops (e.g. blueberry, tart and sweet cherry, floricane‐fruiting summer red raspberry, blackberry, primocane‐fruiting fall raspberries and table grapes) in Pennsylvania and Maryland in 2014. This is the first study determining seasonal occurrence of SWD using a standard commercial lure (Pherocon^® SWD Dual‐Lure^?)‐baited traps in this region. In both states, SWD adults were not captured prior to the month of July, and populations of SWD were found to build up in fruit crops only from mid‐July onwards. This indicates early season fruit crops or varieties are not at risk from SWD fruit injury in these two states. Such early fruit crops, for instance strawberry, sweet and tart cherry, are generally harvested before SWD populations build up in this region. In this context, implications of SWD population in various small fruit crops grown in this region and the utility of SWD Dual‐Lure ^? in season‐long monitoring of SWD population are discussed.     

FDA 2014 survey of eye area cosmetics for microbiological safety

The aim of this work was to evaluate a fungal DNA extraction procedure with the lowest inputs in terms of time as well as of expensive and toxic chemicals, but able to consistently produce genomic DNA of good quality for PCR purposes. Two types of fungal biological material were tested ‐ mycelium and conidia ‐ combined with two protocols for DNA extraction using Sodium Dodecyl Sulphate (SDS) and Cetyl Trimethyl Ammonium Bromide as extraction buffers and glass beads for mechanical disruption of cell walls. Our results showed that conidia and SDS buffer was the combination that lead to the best DNA quality and yield, with the lowest variation between samples. This study clearly demonstrates that it is possible to obtain high yield and pure DNA from pigmented conidia without the use of strong cell disrupting procedures and of toxic reagents.

Significance and Impact of the Study

There are numerous methods for DNA extraction from fungi. Some rely on expensive commercial kits and/or equipments, unavailable for many laboratories, or make use of toxic chemicals such as chloroform, phenol and mercaptoethanol. This study clearly demonstrates that it is possible to obtain high yields of pure DNA from pigmented conidia without the use of strong and expensive cell disrupting procedures and of toxic reagents. The method herein described is simultaneously inexpensive and adequate to DNA extraction from several different types of fungi.     

Identification of putative orthologous genes for the phylogenetic reconstruction of temperate woody bamboos (Poaceae: Bambusoideae)

The temperate woody bamboos (Arundinarieae) are highly diverse in morphology but lack a substantial amount of genetic variation. The taxonomy of this lineage is intractable, and the relationships within the tribe have not been well resolved. Recent studies indicated that this tribe could have a complex evolutionary history. Although phylogenetic studies of the tribe have been carried out, most of these phylogenetic reconstructions were based on plastid data, which provide lower phylogenetic resolution compared with nuclear data. In this study, we intended to identify a set of desirable nuclear genes for resolving the phylogeny of the temperate woody bamboos. Using two different methodologies, we identified 209 and 916 genes, respectively, as putative single copy orthologous genes. A total of 112 genes was successfully amplified and sequenced by next‐generation sequencing technologies in five species sampled from the tribe. As most of the genes exhibited intra‐individual allele heterozygotes, we investigated phylogenetic utility by reconstructing the phylogeny based on individual genes. Discordance among gene trees was observed and, to resolve the conflict, we performed a range of analyses using BUCKy and HybTree. While caution should be taken when inferring a phylogeny from multiple conflicting genes, our analysis indicated that 74 of the 112 investigated genes are potential markers for resolving the phylogeny of the temperate woody bamboos.     

Context‐dependent alarm signalling in an insect

Animals often respond to danger by raising alarm to inform others. Alarm signals come in many different forms, such as visual or mechanical display, sound or odour. Some animals produce vocal alarm signals that vary with the level of danger. For chemical alarm signals, virtually nothing is known about such context‐dependent signalling due to a general notion that alarm pheromones have fixed compositions. Here, we show that larvae of the Western Flower Thrips (Frankliniella occidentalis) produce an alarm pheromone whose composition varies with the level of danger they face: the presence of a relatively harmless predator or a very dangerous predator, that is either actually attacking or not. The frequency of alarm pheromone excretion increases with the level of danger. Moreover, the composition of excreted alarm pheromone varies in the relationship between total and relative amount of the putative two components, decyl acetate (DAc) and dodecyl acetate (DDAc). When pheromone is excreted with a predator present but not attacking, the percentage DDAc increases with the total amount of pheromone. When a predator does attack, however, the relationship between percentage DDAc and total amount of pheromone is reversed. Taken together, the alarm signal of thrips larvae appears to be context dependent, which to our knowledge is the first report of context‐dependent composition of an alarm pheromone.     

Enhanced resistance to soybean cyst nematode Heterodera glycines in transgenic soybean by silencing putative CLE receptors

CLE peptides are small extracellular proteins important in regulating plant meristematic activity through the CLE‐receptor kinase‐WOX signalling module. Stem cell pools in the SAM (shoot apical meristem), RAM (root apical meristem) and vascular cambium are controlled by CLE signalling pathways. Interestingly, plant‐parasitic cyst nematodes secrete CLE‐like effector proteins, which act as ligand mimics of plant CLE peptides and are required for successful parasitism. Recently, we demonstrated that Arabidopsis CLE receptors CLAVATA1 (CLV1), the CLAVATA2 (CLV2)/CORYNE (CRN) heterodimer receptor complex and RECEPTOR‐LIKE PROTEIN KINASE 2 (RPK2), which transmit the CLV3 signal in the SAM, are required for perception of beet cyst nematode Heterodera schachtii CLEs. Reduction in nematode infection was observed in clv1, clv2, crn, rpk2 and combined double and triple mutants. In an effort to develop nematode resistance in an agriculturally important crop, orthologues of Arabidopsis receptors including CLV1, CLV2, CRN and RPK2 were identified from soybean, a host for the soybean cyst nematode Heterodera glycines. For each of the receptors, there are at least two paralogues in the soybean genome. Localization studies showed that most receptors are expressed in the root, but vary in their level of expression and spatial expression patterns. Expression in nematode‐induced feeding cells was also confirmed. In vitro direct binding of the soybean receptors with the HgCLE peptide was analysed. Knock‐down of the receptors in soybean hairy roots showed enhanced resistance to SCN. Our findings suggest that targeted disruption of nematode CLE signalling may be a potential means to engineer nematode resistance in crop plants.     

Ingestible insecticides for spotted wing Drosophila control: a polyol,Erythritol, and an insect growth regulator,Lufenuron

Bioassays tested insecticidal activity of Erythritol from the nutritive sweetener, Truvia, and an insect growth regulator, Lufenuron, against life stages (eggs, larvae, pupae, adults) of Drosophila melanogaster (Meigen) and Drosophila suzukii (Matsumura), the spotted wing Drosophila (SWD). These compounds were chosen for their demonstrated acute toxicity to adult and larval Drosophila and potential use on organic fruit farms. D. melanogaster fed on standard Drosophila diet media moistened with water containing known concentrations of Erythritol. Likewise, SWD consumed standard diet media as well as thawed host fruit (blackberries and blueberries) treated with solutions of Erythritol, Lufenuron or both. During the first bioassay, Erythritol at lower concentrations between 0 and 500 mm (~61 000 ppm) in water and mixed with instant diet media increased adult survival from ~80% to 97% for D. melanogaster and SWD. However, from aqueous concentrations ranging from 1750 (~414 000 ppm) to 2000 mm (~244 000 ppm), Erythritol killed 100% of adult Drosophila in culture vials. One hundred per cent mortality for SWD and D. melanogaster occurred at ≥0.5 m (~61 000 ppm) Erythritol added to diet media or topically applied to host fruit. In a second bioassay, 0.013–1.000 ppm of aqueous Lufenuron, a chitin synthase inhibitor, when added to dry diet media prevented 90–99% of SWD from reaching the pupal stage. In another assay, ~67% of SWD eggs or neonates (early first instars) died inside blackberries pre‐treated with (dipped in) a soapy solution of 10 ppm Lufenuron. Pre‐treating blackberry fruit with an Erythritol–Lufenuron mixture reduced SWD brood survival by 99%. Likewise, during our last fruit‐based bioassay, 98% of eggs and neonates died inside blueberries similarly pre‐treated. During the last experiment, Lufenuron in diet media also rendered adult females sterile. Sterility, however, dissipated over 7 days once females began feeding on a Lufenuron‐free diet media.     

A single semi‐synthetic diet with improved antimicrobial activity for mass rearing of lepidopteran insect pests of cotton and maize

Helicoverpa armigera (Hübner), Earias vittella (Fabricius), Spodoptera litura (Fabricius), Spodoptera exigua (Hübner) (all Lepidoptera: Noctuidae), Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), and Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) are the major pests of cotton and maize. Mass‐rearing of these insects under controlled conditions is necessary to obtain the numbers needed to conduct bioassays to screen insecticides, proteins, and other compounds, as tools for insect pest management. We present a diet suitable for rearing the six lepidopteran pests (five cotton and one maize pest). We further show that this diet is on par with or superior to the published diet recipes for each of the insect species, which were studied for three generations. We also discuss the advantages of antimicrobials other than formalin for keeping microbial growth under check. A combination of antimicrobial solution and benomyl provided effective control and suppressed the growth of microbes for a longer period than a formalin‐containing diet. A common diet for six pests provide opportunities for automation of diet preparation in addition to improved throughput and consistency in the process, while eliminating diet‐batch related errors.     

The effect of Wolbachia on the lifetime reproductive success of its insect host in the field

Wolbachia is a widespread endosymbiont that induces dramatic manipulations of its host's reproduction. Although there has been substantial progress in the developing theory for Wolbachia–host interactions and in measuring the effects of Wolbachia on host fitness in the laboratory, there is a widely recognized need to quantify the effects of Wolbachia on the host fitness in the field. The wasp Anagrus sophiae, an egg parasitoid of planthoppers, carries a Wolbachia strain that induces parthenogenesis, but its effects on the fitness of its Anagrus host are unknown. We developed a method to estimate the realized lifetime reproductive success of female wasps by collecting them soon after they die naturally in the field, counting the number of eggs remaining in their ovaries and quantifying Wolbachia density in their body. We sampled from a highly infected A. sophiae population and found no evidence for Wolbachia virulence and possible evidence for positive effects of Wolbachia on realized reproductive success.     

The nutritional landscape of host plants for a specialist insect herbivore

相似文献   

Surveys reveal a complex association of phytoplasmas and viruses with the blueberry stunt disease on Canadian blueberry farms

Surveys for phytoplasmas and viruses were conducted during September 2014 and 2015 on highbush blueberry farms in the Région Montérégie, Quebec. Total DNA and RNA were extracted from blueberry bushes showing blueberry stunt (BBS) symptoms and from symptomless blueberry bushes, and utilised as templates for PCR and RT‐PCR assays, respectively. Phytoplasma DNA was amplified with universal phytoplasma primers that target the 16S rRNA, secA and secY genes from 12 out of 40 (30%) plants tested. Based on 16S rRNA, secA and secY gene sequence identity, phylogenetic clustering, actual and in silico RFLP analyses, phytoplasma strains associated with BBS disease in Quebec were identified as ‘Candidatus Phytoplasma asteris’‐related strains, closely related to the BBS Michigan phytoplasma strain (16SrI‐E). The secY gene sequence‐based single nucleotide polymorphism analysis revealed that one of the BBS phytoplasma strains associated with a leaf marginal yellowing is a secY‐I RFLP variant of the subgroup 16SrI‐E. Two viruses were detected in blueberry bushes. The Blueberry Red Ringspot Virus (BRRV) was found in a single infection in the cultivar Bluecrop with no apparent typical BRRV symptoms. The Tobacco Ringspot Virus (TRSV) was found singly infecting blueberry plants and co‐infecting a BBS phytoplasma‐infected blueberry cv. Bluecrop plant. This is the first report of TRSV in the cv. Bluecrop in Quebec. The Quebec BBS phytoplasma strain was identified in the leafhopper Graphocephala fennahi, which suggests that G. fennahi may be a potential vector for the BBS phytoplasma. The BBS disease shows a complex aetiology and epidemiology; therefore, prompt actions must be developed to support focused BBS integrated management strategies.     

Defensive insect symbiont leads to cascading extinctions and community collapse

Animals often engage in mutualistic associations with microorganisms that protect them from predation, parasitism or pathogen infection. Studies of these interactions in insects have mostly focussed on the direct effects of symbiont infection on natural enemies without studying community‐wide effects. Here, we explore the effect of a defensive symbiont on population dynamics and species extinctions in an experimental community composed of three aphid species and their associated specialist parasitoids. We found that introducing a bacterial symbiont with a protective (but not a non‐protective) phenotype into one aphid species led to it being able to escape from its natural enemy and increase in density. This changed the relative density of the three aphid species which resulted in the extinction of the two other parasitoid species. Our results show that defensive symbionts can cause extinction cascades in experimental communities and so may play a significant role in the stability of consumer‐herbivore communities in the field.     

Environmental DNA for the enumeration and management of Pacific salmon

Pacific salmon are a keystone resource in Alaska, generating annual revenues of well over ~US$500 million/year. Due to their anadromous life history, adult spawners distribute amongst thousands of streams, posing a huge management challenge. Currently, spawners are enumerated at just a few streams because of reliance on human counters and, rarely, sonar. The ability to detect organisms by shed tissue (environmental DNA, eDNA) promises a more efficient counting method. However, although eDNA correlates generally with local fish abundances, we do not know if eDNA can accurately enumerate salmon. Here we show that daily, and near‐daily, flow‐corrected eDNA rate closely tracks daily numbers of returning sockeye and coho spawners and outmigrating sockeye smolts. eDNA thus promises accurate and efficient enumeration, but to deliver the most robust numbers will need higher‐resolution stream‐flow data, at‐least‐daily sampling, and a focus on species with simple life histories, since shedding rate varies amongst jacks, juveniles, and adults.     

A DNA barcode library for 5,200 German flies and midges (Insecta: Diptera) and its implications for metabarcoding‐based biomonitoring

This study summarizes results of a DNA barcoding campaign on German Diptera, involving analysis of 45,040 specimens. The resultant DNA barcode library includes records for 2,453 named species comprising a total of 5,200 barcode index numbers (BINs), including 2,700 COI haplotype clusters without species‐level assignment, so called “dark taxa.” Overall, 88 out of 117 families (75%) recorded from Germany were covered, representing more than 50% of the 9,544 known species of German Diptera. Until now, most of these families, especially the most diverse, have been taxonomically inaccessible. By contrast, within a few years this study provided an intermediate taxonomic system for half of the German Dipteran fauna, which will provide a useful foundation for subsequent detailed, integrative taxonomic studies. Using DNA extracts derived from bulk collections made by Malaise traps, we further demonstrate that species delineation using BINs and operational taxonomic units (OTUs) constitutes an effective method for biodiversity studies using DNA metabarcoding. As the reference libraries continue to grow, and gaps in the species catalogue are filled, BIN lists assembled by metabarcoding will provide greater taxonomic resolution. The present study has three main goals: (a) to provide a DNA barcode library for 5,200 BINs of Diptera; (b) to demonstrate, based on the example of bulk extractions from a Malaise trap experiment, that DNA barcode clusters, labelled with globally unique identifiers (such as OTUs and/or BINs), provide a pragmatic, accurate solution to the “taxonomic impediment”; and (c) to demonstrate that interim names based on BINs and OTUs obtained through metabarcoding provide an effective method for studies on species‐rich groups that are usually neglected in biodiversity research projects because of their unresolved taxonomy.     

悬钩子属DNA条形码通用序列的初步筛选

为了建立悬钩子属（Rubus）植物的DNA条形码分子鉴定技术,筛选获得适用于悬钩子属植物的通用条形码序列。该研究基于GenBank数据对ITS、ITS2、matK、rbcL、trnH-psbA、trnL-trnF 6个DNA条形码序列进行了遗传变异、barcoding gap、建树等评估分析。结果显示,trnH-psbA、matK、rbcL、rtnL-trnF的种内变异与种间变异差异较大,变异分辨率分别为97.32%、83.33%、79.07%、64.95%,存在较大的barcoding gap;NJ一致树分析显示,matK的单系性比例最高（67%）,其次为trnH-psbA（64%）,rtnL-trnF（43%）,rbcL（30%）。结果表明,悬钩子属植物的matK与trnH-psbA序列种内变异与种间变异差异较大,能较好地区分不同物种,具有较大的鉴定潜力。建议将matK和trnH-psbA作为悬钩子属植物鉴定的核心条形码序列,rtnL-trnF、rbcL作为辅助条形码序列。     

Chemical mimicry of insect oviposition sites: a global analysis of convergence in angiosperms

Floral mimicry of decaying plant or animal material has evolved in many plant lineages and exploits, for the purpose of pollination, insects seeking oviposition sites. Existing studies suggest that volatile signals play a particularly important role in these mimicry systems. Here, we present the first large‐scale phylogenetically informed study of patterns of evolution in the volatile emissions of plants that mimic insect oviposition sites. Multivariate analyses showed strong convergent evolution, represented by distinct clusters in chemical phenotype space of plants that mimic animal carrion, decaying plant material, herbivore dung and omnivore/carnivore faeces respectively. These plants deploy universal infochemicals that serve as indicators for the main nutrients utilised by saprophagous, coprophagous and necrophagous insects. The emission of oligosulphide‐dominated volatile blends very similar to those emitted by carrion has evolved independently in at least five plant families (Annonaceae, Apocynaceae, Araceae, Orchidaceae and Rafflesiaceae) and characterises plants associated mainly with pollination by necrophagous flies and beetles.     

Daphnia diversity on the Tibetan Plateau measured by DNA taxonomy

Daphnia on the Tibetan Plateau has been little studied, and information on species diversity and biogeography is lacking. Here, we conducted a 4‐year survey using the barcoding fragment of the mitochondrial COI gene to determine the distribution and diversity of Daphnia species found across the Plateau. Our results show that species richness is higher than previously thought, with total described and provisional species number doubling from 5 to 10. Six of the taxonomic units recovered by DNA taxonomy agreed well with morphology, but DNA barcoding distinguished three clades each for the D. longispina (D. galeata, D. dentifera, and D. longispina) and D. pulex (D. pulex, D. cf. tenebrosa, and D. pulicaria) complexes. The sequence divergence between congeneric species varied within a large range, from 9.25% to 30.71%. The endemic D. tibetana was the most common and widespread species, occurring in 12 hyposaline to mesosaline lakes. The lineage of D. longispina is the first confirmed occurrence in west Tibet.