Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| response of economically important aphids to components of hemizygia petiolata essential oil. | the essential oil of hemizygia petiolata ashby (lamiaceae) contains high levels (>70%) of the sesquiterpene (e)-beta-farnesene, the alarm pheromone for many economically important aphid species. in order to test the suitability of h. petiolata oil as a source of (e)-beta-farnesene for use in new integrated aphid control strategies, behavioural responses of pest aphid species were studied in laboratory and field experiments. in alarm pheromone assays the peach-potato aphid, myzus persicae sulzer, ... | 2005 | 16059962 |
| nutrient absorption by aphidius ervi larvae. | it is well documented that in the model system aphidius ervi haliday (hymenoptera, braconidae)/acyrthosiphon pisum (harris) (homoptera, aphididae) host regulation by the parasitoid larva induces in the aphid haemolymph major changes of the titer of nutritional compounds such as proteins, acylglycerols and free amino acids, in order to meet the stage-specific demands of the developing larva. since little is known about how the larva absorbs these mobilized nutritional resources, nutrient absorpti ... | 2005 | 16085087 |
| resistance is costly: trade-offs between immunity, fecundity and survival in the pea aphid. | parasitoids are among the most important natural enemies of insects in many environments. acyrthosiphon pisum, the pea aphid, is a common pest of the leguminous crops in temperate regions. pea aphids are frequently attacked by a range of endoparasitic wasps, including the common aphidiine, aphidius ervi. immunity to parasitoid attack is thought to involve secondary symbiotic bacteria, the presence of which is associated with the death of the parasitoid egg. it has been suggested that there is a ... | 2005 | 16096092 |
| variation in resistance to parasitism in aphids is due to symbionts not host genotype. | natural enemies are important ecological and evolutionary forces, and heritable variation in resistance to enemies is a prerequisite for adaptive responses of populations. such variation in resistance has been previously documented for pea aphids (acyrthosiphon pisum) attacked by the parasitoid wasp aphidius ervi. although the variation was presumed to reflect genotypic differences among the aphids, another potential source of resistance to a. ervi is infection by the facultative bacterial symbi ... | 2005 | 16120675 |
| development and reproduction of adalia bipunctata (coleoptera: coccinellidae) on eggs of ephestia kuehniella (lepidoptera: phycitidae) and pollen. | due to growing criticism over the use of non-indigenous coccinellids, the two-spot ladybird, adalia bipunctata (l.), has enjoyed increasing attention for aphid biocontrol in europe. in the current study, eggs of the mediterranean flour moth, ephestia kuehniella zeller, whether or not supplemented with bee pollen, were evaluated as a factitious food for larvae and adults of a. bipunctata. the predator showed slower larval development and lower survival when reared on live pea aphids, acyrthosipho ... | 2005 | 16144016 |
| the players in a mutualistic symbiosis: insects, bacteria, viruses, and virulence genes. | aphids maintain mutualistic symbioses involving consortia of coinherited organisms. all possess a primary endosymbiont, buchnera, which compensates for dietary deficiencies; many also contain secondary symbionts, such as hamiltonella defensa, which confers defense against natural enemies. genome sequences of uncultivable secondary symbionts have been refractory to analysis due to the difficulties of isolating adequate dna samples. by amplifying dna from hemolymph of infected pea aphids, we obtai ... | 2005 | 16195380 |
| characterization of a facultative endosymbiotic bacterium of the pea aphid acyrthosiphon pisum. | the pea aphid u-type symbiont (paus) was investigated to characterize its microbiological properties. fluorescence in situ hybridization (fish) and electron microscopy revealed that paus was a rod-shaped bacterium found in three different locations in the body of the pea aphid acyrthosiphon pisum: sheath cells, secondary mycetocytes, and hemolymph. artificial transfer experiments revealed that paus could establish stable infection and vertical transmission when introduced into uninfected pea aph ... | 2005 | 15690225 |
| a novel fatty acid binding protein produced by teratocytes of the aphid parasitoid aphidius ervi. | aphidius ervi is an endophagous braconid, parasitoid of the pea aphid, acyrthosiphon pisum. a. ervi teratocytes, deriving from the dissociation of the embryonic serosa, synthesize and release two major proteins into the host haemocoel. the gene of one of these proteins has been cloned and characterized. this gene codes for a 15.8 kda protein belonging to the fatty acid binding protein (fabp) family, named ae-fabp (a. ervi-fabp). it is abundantly present in the host haemolymph when the parasitoid ... | 2005 | 15796753 |
| transcriptome analysis of the aphid bacteriocyte, the symbiotic host cell that harbors an endocellular mutualistic bacterium, buchnera. | aphids possess bacteriocytes, cells specifically differentiated to harbor obligatory mutualistic bacteria of the genus buchnera, which have lost many genes that are essential for common bacterial functions. to understand the host's role in maintaining the symbiotic relationship, bacteriocytes were isolated from the pea aphid, acyrthosiphon pisum, and the host transcriptome was investigated by using est analysis and real-time quantitative rt-pcr. a number of genes were highly expressed specifical ... | 2005 | 15800043 |
| aphid protected from pathogen by endosymbiont. | aphids are associated with several facultative bacterial endosymbionts that may influence their interactions with other organisms. we show here that one of the three most common facultative symbionts of pea aphid (acyrthosiphon pisum), the bacterium regiella insecticola, has a major effect on host resistance to a fungal pathogen. experimental establishment of the bacterium in uninfected aphid clones led to higher survival after fungal attack. the bacteria also increased the aphid's inclusive fit ... | 2005 | 16357252 |
| attributes of bean yellow mosaic potyvirus transmission from clover to snap beans by four species of aphids (homoptera: aphididae). | after characterization of the natural spread of necrosis-inducing bean yellow mosaic potyvirus (family potyviridae, genus potyvirus, bymv(n)), nonpersistently transmitted from clover, trifolium repens l., to an adjacent field of snap bean, phaseolus vulgaris l., in western oregon, we established a study site enabling us to investigate the virus reservoir, to observe en masse transmission of bymv(n) to bean plants, and to identify aphid species associated with virus spread. colonies of myzus pers ... | 2005 | 16539099 |
| the effect of predators and hymenopterous parasites on population fluctuations of alfalfa aphids. | among alfalfa pests in iran three aphid species, green alfalfa aphid acyrthosiphon pisum harris spotted alfalfa aphid therioaphis trifolii forma maculata buckton and blue alfalfa aphid, acyrthosiphon kondoi shinji are important pests. the green alfalfa aphid can be observed all along the growing season particularly from late may to mid june at karaj climate conditions. during this period, the mean monthly maximum temperature and relative humidity were about 28 degrees c and 60-65% respectively. ... | 2005 | 16628912 |
| horizontal transfer of bacterial symbionts: heritability and fitness effects in a novel aphid host. | members of several bacterial lineages are known only as symbionts of insects and move among hosts through maternal transmission. such vertical transfer promotes strong fidelity within these associations, favoring the evolution of microbially mediated effects that improve host fitness. however, phylogenetic evidence indicates occasional horizontal transfer among different insect species, suggesting that some microbial symbionts retain a generalized ability to infect multiple hosts. here we examin ... | 2005 | 16332777 |
| aster self-organization at meiosis: a conserved mechanism in insect parthenogenesis? | unfertilized eggs usually lack maternal centrosomes and cannot develop without sperm contribution. however, several insect species lay eggs that develop to adulthood as unfertilized in the absence of a preexisting centrosome. we report that the oocyte of the parthenogenetic viviparous pea aphid acyrthosiphon pisum is able to self-organize microtubule-based asters, which in turn interact with the female chromatin to form the first mitotic spindle. this mode of reproduction provides a good system ... | 2005 | 15649474 |
| application of dl-beta-aminobutyric acid (baba) as a root drench to legumes inhibits the growth and reproduction of the pea aphid acyrthosiphon pisum (hemiptera: aphididae). | dl-beta-aminobutyric acid (baba) is a non-protein amino acid that is an effective inducer of resistance against a variety of plant pathogens. however, examples of baba-induced resistance against insect herbivores have not been reported. we applied baba as a soil drench to legumes and monitored its effects on the pea aphid acyrthosiphon pisum (harris). on tic bean (vicia faba var. minor), baba increased aphid mortality, caused a reduction in the mean relative growth rate of individual insects and ... | 2005 | 16197565 |
| the significance of gut sucrase activity for osmoregulation in the pea aphid, acyrthosiphon pisum. | the osmotic pressure of the body fluids of aphids is lower than in their diet of plant phloem sap. it is hypothesised that aphids reduce the osmotic pressure of ingested food by sucrase-mediated hydrolysis of dietary sucrose to glucose and fructose, and the polymerisation of glucose into oligosaccharides of low osmotic pressure per hexose unit. to test this hypothesis, the impact of the alpha-glucosidase inhibitor acarbose on the sugar relations and osmoregulation of aphids was explored. acarbos ... | 2005 | 16169004 |
| effect of precocene ii on fatty acid metabolism in the pea aphid, acyrthosiphon pisum, under cold stress. | pea aphids, acyrthosiphon pisum (harris), reared at 10 degrees c contain higher levels of fatty acids than those reared at 25 degrees c. this is primarily the result of an accumulation of triacylglycerols containing myristic acid. when aphids reared at 25 degrees c were transferred to 10 degrees c there was a gradual increase in triacylglycerol content that reached a maximum at 16 days post-transfer. treatment of aphids with precocene ii prior to transfer to 10 degrees c blocked the accumulation ... | 2005 | 15890184 |
| the importance of antennae for pea aphid wing induction in the presence of natural enemies. | the pea aphid acyrthosiphon pisum harris has been shown to produce an increasing proportion of winged morphs among its offspring when exposed to natural enemies, in particular hoverfly larvae, lacewing larvae, adult and larval ladybirds and aphidiid parasitoids. while these results suggest that wing induction in the presence of predators and parasitoids is a general response of the pea aphid, the cues and mechanisms underlying this response are still unclear. tactile stimuli and the perception o ... | 2005 | 15877861 |
| prodrug-oriented molecular design of neonicotinoids: preparation of imidacloprid-related 5,5-dimethoxy-1,3-diazacyclohexane derivatives and their insecticidal activity. | prodrug-oriented molecular design was attempted for the potent acyclic neonicotinoid insecticide, clothianidin (1-(2-chloro-5-thiazolylmethyl)-3-methyl-2-nitroguanidine). molecules bearing a ch2coch2 bridge linking the 1,3-nh ends of clothianidin or their acetals would possibly be hydrolyzed, regenerating the mother compounds. this strategy was used to prepare seven acetals of clothianidin-based molecules that combined 2-chloro-5-thiazolylmethyl, 6-chloro-3-pyridylmethyl or 3-tetrahydrofurfuryl ... | 2005 | 15849408 |
| genetic variation for an aphid wing polyphenism is genetically linked to a naturally occurring wing polymorphism. | many polyphenisms are examples of adaptive phenotypic plasticity where a single genotype produces distinct phenotypes in response to environmental cues. such alternative phenotypes occur as winged and wingless parthenogenetic females in the pea aphid (acyrthosiphon pisum). however, the proportion of winged females produced in response to a given environmental cue varies between clonal genotypes. winged and wingless phenotypes also occur in males of the sexual generation. in contrast to parthenog ... | 2005 | 15817441 |
| attraction of two lacewing species to volatiles produced by host plants and aphid prey. | it is well documented that host-related odors enable many species of parasitoids and predatory insects to locate their prey and prey habitats. this study reports the first characterization of prey and prey host odor reception in two species of lacewings, chrysoperla carnea (say) and chrysopa oculata l. 2-phenylethanol, one of the volatiles emitted from their prey's host plants (alfalfa and corn) evoked a significant eag response from antennae of c. carnea. traps baited with this compound attract ... | 2005 | 15812573 |
| aphid infestation causes different changes in carbon and nitrogen allocation in alfalfa stems as well as different inhibitions of longitudinal and radial expansion. | alfalfa (medicago sativa) stem elongation is strongly reduced by a pea aphid (acyrthosiphon pisum harris) infestation. as pea aphid is a phloem feeder that does not transmit virus or toxins, assimilate withdrawal is generally considered as the main mechanism responsible for growth reduction. using a kinematic analysis, we investigated the spatial distributions of relative elemental growth rates of control and infested alfalfa stems. the water, carbon, and nitrogen contents per unit stem length w ... | 2005 | 15778456 |
| genetic mapping of aphicarus -- a sex-linked locus controlling a wing polymorphism in the pea aphid (acyrthosiphon pisum). | we have initiated research to determine the genetic basis of a male wing polymorphism in the pea aphid acyrthosiphon pisum (hemiptera: aphididae). previous studies showed that this polymorphism is controlled by a single biallelic locus, which we name aphicarus (api), on the x chromosome. our objectives were to confirm that api segregates as a polymorphism of a single gene on the x chromosome, and to obtain molecular markers flanking api that can be used as a starting point for high-resolution ge ... | 2005 | 15674387 |
| back to the future: genetic correlations, adaptation and speciation. | genetic correlations can affect the course of phenotypic evolution. although genetic correlations among traits are a common feature of quantitative genetic analyses, they have played a very minor role in recent linkage-map based analyses of the genetic architecture of quantitative traits. here, we use our work on host-associated races in pea aphids to illustrate how quantitative trait locus (qtl) mapping can be used to test specific hypotheses about how genetic correlations may facilitate ecolog ... | 2005 | 15881687 |
| large-scale gene discovery in the pea aphid acyrthosiphon pisum (hemiptera). | aphids are the leading pests in agricultural crops. a large-scale sequencing of 40,904 ests from the pea aphid acyrthosiphon pisum was carried out to define a catalog of 12,082 unique transcripts. a strong at bias was found, indicating a compositional shift between drosophila melanogaster and a. pisum. an in silico profiling analysis characterized 135 transcripts specific to pea-aphid tissues (relating to bacteriocytes and parthenogenetic embryos). this project is the first to address the geneti ... | 2006 | 16542494 |
| the evolution of the histone methyltransferase gene su(var)3-9 in metazoans includes a fusion with and a re-fission from a functionally unrelated gene. | in eukaryotes, histone h3 lysine 9 (h3k9) methylation is a common mechanism involved in gene silencing and the establishment of heterochromatin. the loci of the major heterochromatic h3k9 methyltransferase su(var)3-9 and the functionally unrelated gamma subunit of the translation initiation factor eif2 are fused in drosophila melanogaster. here we examined the phylogenetic distribution of this unusual gene fusion and the molecular evolution of the h3k9 hmtase su(var)3-9. | 2006 | 16512904 |
| infectivity of nanovirus dnas: induction of disease by cloned genome components of faba bean necrotic yellows virus. | circumstantial evidence suggests that the genome of faba bean necrotic yellows virus (fbnyv), a nanovirus, consists of eight distinct, circular, single-stranded dnas, each of about 1 kb and encoding only one protein. here, the use of cloned full-length fbnyv dnas for reproducing fbnyv-like symptoms in vicia faba, the principal natural host of fbnyv, is reported. characteristic symptoms of fbnyv infection were obtained in faba bean plants following biolistic dna delivery or agroinoculation with a ... | 2006 | 16690940 |
| costs and benefits of a superinfection of facultative symbionts in aphids. | symbiotic associations between animals and inherited micro-organisms are widespread in nature. in many cases, hosts may be superinfected with multiple inherited symbionts. acyrthosiphon pisum (the pea aphid) may harbour more than one facultative symbiont (called secondary symbionts) in addition to the obligate primary symbiont, buchnera aphidicola. previously we demonstrated that, in a controlled genetic background, a. pisum infected with either serratia symbiotica or hamiltonella defensa (calle ... | 2006 | 16720402 |
| learning by the parasitoid wasp, aphidius ervi (hymenoptera: braconidae), alters individual fixed preferences for pea aphid color morphs. | learning, defined as changes in behavior that occur due to past experience, has been well documented for nearly 20 species of hymenopterous parasitoids. few studies, however, have explored the influence of learning on population-level patterns of host use by parasitoids in field populations. our study explores learning in the parasitoid aphidius ervi haliday that attacks pea aphids, acyrthosiphon pisum (harris). we used a sequence of laboratory experiments to investigate whether there is a learn ... | 2006 | 16858585 |
| hundreds of flagellar basal bodies cover the cell surface of the endosymbiotic bacterium buchnera aphidicola sp. strain aps. | buchnera aphidicola is the endosymbiotic bacterium of the pea aphid. due to its small genome size, buchnera lacks many essential genes for autogenous life but obtains nutrients from the host. although the buchnera cell is nonmotile, it retains clusters of flagellar genes that lack the late genes necessary for motility, including the flagellin gene. in this study, we show that the flagellar genes are actually transcribed and translated and that the buchnera cell surface is covered with hundreds o ... | 2006 | 16952945 |
| codon usage bias and trna over-expression in buchnera aphidicola after aromatic amino acid nutritional stress on its host acyrthosiphon pisum. | codon usage bias and relative abundances of trna isoacceptors were analysed in the obligate intracellular symbiotic bacterium, buchnera aphidicola from the aphid acyrthosiphon pisum, using a dedicated 35mer oligonucleotide microarray. buchnera is archetypal of organisms living with minimal metabolic requirements and presents a reduced genome with high-evolutionary rate. codonusage in buchnera has been overcome by the high mutational bias towards at bases. however, several lines of evidence for c ... | 2006 | 16963497 |
| cytochrome c oxidase mrna as an internal control for detection of potato virus y and potato leafroll virus from single aphids by a co-amplification rt-pcr assay. | using cytochrome c oxidase subunit 1 (cox1) mrna as the internal control, a triplex reverse transcription-polymerase chain reaction (rt-pcr) for detection of potato virus y (pvy) and potato leafroll virus (plrv) with co-amplification of cox1 from single specimens of various aphid species has been developed. partial length cdna of cox1 from green peach aphid, myzus persicae (sulzer), potato aphid, macrosiphum euphorbiae (thomas), buckthorn aphid, aphis nasturtii (kaltenbach), and pea aphid, acyrt ... | 2006 | 17010449 |
| covariance of phenotypically plastic traits induces an adaptive shift in host selection behaviour. | flexibility in adult body size allows generalist parasitoids to use many host species at a cost of producing a range of adult sizes. consequently, host selection behaviour must also maintain a level of flexibility as adult size is related to capture efficiency. in the present study, we investigated covariance of two plastic traits--size at pupation and host size selection behaviour-using aphidius ervi reared on either acyrthosiphon pisum or aulacorthum solani, generating females of disparate siz ... | 2006 | 17015365 |
| effects of hydrophilic and hydrophobic kaolin-based particle films on pea aphid (homoptera: aphididae) and its entomopathogen pandora neoaphidis (entomophthorales: entomophthoraceae). | hydrophobic and hydrophilic kaolin-based particle films are effective for control of insect pests in certain agricultural crops. how these products interact with potential biological control agents is not well documented. this study was conducted to evaluate the effects of the hydrophobic (m96-018) and hydrophilic (surround wp) kaolin-based particle films (engelhard corporation, iselin, nj) on pea aphid, acyrthosiphon pisum (harris), on peas (pisum spp.), and on the fungal aphid pathogen pandora ... | 2006 | 16573319 |
| symbiont modifies host life-history traits that affect gene flow. | the evolution of herbivore-host plant specialization requires low levels of gene flow between populations on alternate plant species. accordingly, selection for host plant specialization is most effective when genotypes have minimal exposure to, and few mating opportunities with individuals from, alternate habitats. maternally transmitted bacterial symbionts are common in insect herbivores and can influence host fecundity under a variety of conditions. symbiont-mediated effects on host life-hist ... | 2006 | 16600884 |
| phylogeny of the sex-determining gene sex-lethal in insects. | the sex-lethal (sxl) protein belongs to the family of rna-binding proteins and is involved in the regulation of pre-mrna splicing. sxl has undergone an obvious change of function during the evolution of the insect clade. the gene has acquired a pivotal role in the sex-determining pathway of drosophila, although it does not act as a sex determiner in non-drosophilids. we collected sxl sequences of insect species ranging from the pea aphid (acyrtho siphom pisum) to drosophila melanogaster by searc ... | 2006 | 16604108 |
| functional genomics of buchnera and the ecology of aphid hosts. | in many animal groups, mutualistic bacterial symbionts play a central role in host ecology, by provisioning rare nutrients and thus enabling specialization on restricted diets. among such symbionts, genomic studies are most advanced for buchnera, the obligate symbiont of aphids, which feed on phloem sap. the contents of the highly reduced buchnera genomes have verified its role in aphid nutrition. comparisons of buchnera gene sets indicate ongoing, irreversible gene losses that are expected to a ... | 2006 | 16626452 |
| a dual-genome microarray for the pea aphid, acyrthosiphon pisum, and its obligate bacterial symbiont, buchnera aphidicola. | the best studied insect-symbiont system is that of aphids and their primary bacterial endosymbiont buchnera aphidicola. buchnera inhabits specialized host cells called bacteriocytes, provides nutrients to the aphid and has co-speciated with its aphid hosts for the past 150 million years. we have used a single microarray to examine gene expression in the pea aphid, acyrthosiphon pisum, and its resident buchnera. very little is known of gene expression in aphids, few studies have examined gene exp ... | 2006 | 16536873 |
| costs and benefits of symbiont infection in aphids: variation among symbionts and across temperatures. | symbiosis is prevalent throughout the tree of life and has had a significant impact on the ecology and evolution of many bacteria and eukaryotes. the benevolence of symbiotic interactions often varies with the environment, and such variation is expected to play an important role in shaping the prevalence and distributions of symbiosis throughout nature. in this study, we examine how the fitness of aphids is influenced by infection with one of three maternally transmitted bacteria, 'candidatus se ... | 2006 | 16537132 |
| effect of fungal infection on the reproductive potential of aphids and their progeny. | the effect of infection by pandora neoaphidis and beauveria bassiana on the reproductive potential of the pea aphid, acyrthosiphon pisum, and their progeny was assessed. infection by either p. neoaphidis or b. bassiana reduced the number of nymphs produced within 24 h of inoculation and over the entire infection period compared to uninfected aphids. however, infection by either p. neoaphidis or b. bassiana for 24 or 72 h did not alter the intrinsic rate of increase of the host aphid's progeny. t ... | 2006 | 16410010 |
| phloem-sap feeding by animals: problems and solutions. | the incidence of phloem sap feeding by animals appears paradoxical. although phloem sap is nutrient-rich compared with many other plant products and generally lacking in toxins and feeding deterrents, it is consumed as the dominant or sole diet by a very restricted range of animals, exclusively insects of the order hemiptera. these insects display two sets of adaptations. first, linked to the high ratio of non-essential:essential amino acids in phloem sap, these insects contain symbiotic micro-o ... | 2006 | 16449374 |
| the phytopathogen dickeya dadantii (erwinia chrysanthemi 3937) is a pathogen of the pea aphid. | dickeya dadantii (erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. the sequencing of its genome identified four genes encoding homologues of the cyt family of insecticidal toxins from bacillus thuringiensis, which are not present in the close relative pectobacterium carotovorum subsp. atrosepticum. the pathogenicity of d. dadantii was tested on the pea aphid acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either ... | 2006 | 16517643 |
| aphid clonal resistance to a parasitoid fails under heat stress. | parasitoid virulence and host resistance are complex interactions depending on metabolic rate and cellular activity, which in aphids additionally implicate heritable secondary symbionts among the enterobacteriaceae. as performance of the parasitoid, the aphid host and its symbionts may differentially respond to temperature, the success or failure of aphid parasitism is difficult to predict when temperature varies. we tested the hypothesis that resistance of the pea aphid acyrthosiphon pisum to t ... | 2006 | 16307754 |
| a simple wax-embedding method for isolation of aphid hemolymph for detection of luteoviruses in the hemocoel. | a protocol for isolating hemolymph from viruliferous aphids has been developed. this method uses warm melted wax to immobilize the aphid. following removal of a hind leg, the hemolymph can be collected readily. flushing with rnase-free water allows for collection of sufficient hemolymph for rna extraction from individual aphids. the extracted rna was successfully used for detection of barley yellow dwarf virus (bydv) and pea enation mosaic virus (pemv) from individual viruliferous rhopalosiphum ... | 2006 | 16307802 |
| inter- and intra-guild interactions related to aphids in nettle (urtica dioica l.) strips closed to field crops. | a field experiment designed to assess the biodiversity related to nettle strips closed to crops, and more particularly the aphid and related beneficial populations, was established in experimental farm located in gembloux (belgium). margin strips of nettle (urtica dioica) closed to wheat (triticum aestivum), green pea (pisum sativum) and rape (brassicae napus) fields were investigated. the diversity, abundance of aphids and related predators were analysed according to the plant crop species and ... | 2006 | 17385508 |
| characterization of a membrane-bound aminopeptidase purified from acyrthosiphon pisum midgut cells. a major binding site for toxic mannose lectins. | a single membrane-bound aminopeptidase n (apn) occurs in the pea aphid (acyrthosiphon pisum harris) midgut, with a ph optimum of 7.0, pi of 8.1 and molecular mass of 130 kda. this enzyme accounts for more than 15.6% of the total gut proteins. after being solubilized in detergent, apn was purified to homogeneity. the enzyme is a glycoprotein rich in mannose residues, which binds the entomotoxic lectins of the concanavalin family. the internal sequence of apn is homologous with a conservative doma ... | 2006 | 17212776 |
| population differentiation and genetic variation in host choice among pea aphids from eight host plant genera. | habitat choice plays a critical role in the processes of host range evolution, specialization, and ecological speciation. pea aphid, acyrthosiphon pisum, populations from alfalfa and red clover in eastern north america are known to be genetically differentiated and show genetic preferences for the appropriate host plant. this species feeds on many more hosts, and here we report a study of the genetic variation in host plant preference within and between pea aphid populations collected from eight ... | 2006 | 17017058 |
| temporal habitat variability and the maintenance of sex in host populations of the pea aphid. | the evolutionary maintenance of sex, despite competition from asexual reproduction, has long intrigued the evolutionary biologists owing to its numerous apparent short-term costs. in aphids, winter climate is expected to determine the maintenance of sexual lineages in the high latitude zones owing to their exclusive ability to produce frost-resistant eggs. however, diverse reproductive modes may coexist at a local scale where climatic influence is counteracted by microgeographical factors. in th ... | 2006 | 17015368 |
| the pea aphid, acyrthosiphon pisum: an emerging genomic model system for ecological, developmental and evolutionary studies. | aphids display an abundance of adaptations that are not easily studied in existing model systems. here we review the biology of a new genomic model system, the pea aphid, acyrthosiphon pisum. we then discuss several phenomena that are particularly accessible to study in the pea aphid: the developmental genetic basis of polyphenisms, aphid-bacterial symbioses, the genetics of adaptation and mechanisms of virus transmission. the pea aphid can be maintained in the laboratory and natural populations ... | 2006 | 16850403 |
| effect of low and high-saponin lines of alfalfa on pea aphid. | pea aphid fed on a high-saponin line of alfalfa showed reduction of reproduction and survival, and disturbance in development of its population. this line negatively influenced aphid probing behaviour, particularly prolonging the non-probing period and probing of the peripheral tissues (epidermis and mesophyll) and shortening the period of phloem sap ingestion. the high-saponin line of alfalfa differed from the low-saponin one by the presence of zanhic acid tridesmoside and a higher level of 3-g ... | 2006 | 16740274 |
| ecological specialization correlates with genotypic differentiation in sympatric host-populations of the pea aphid. | the pea aphid, acyrthosiphon pisum, encompasses distinct host races specialized on various fabaceae species, but the extent of genetic divergence associated with ecological specialization varies greatly depending on plant and geographic origins of aphid populations. here, we studied the genetic structure of french sympatric pea aphid populations collected on perennial (pea and faba bean) and annual (alfalfa and red clover) hosts using 14 microsatellite loci. classical and bayesian population gen ... | 2006 | 16599915 |
| sweet problems: insect traits defining the limits to dietary sugar utilisation by the pea aphid, acyrthosiphon pisum. | plant phloem sap is an extreme diet for animals, partly because of its high and variable sugar content. the physiological and feeding traits of the pea aphid acyrthosiphon pisum that define the upper and lower limits to the range of dietary sucrose concentrations utilised by this insect were determined principally using chemically defined diets containing 0.125-1.5 mol l(-1) sucrose. on the diets with 0.125 mol l(-1) and 1.5 mol l(-1) sucrose, the aphids died as larvae within 8 and 14 days of bi ... | 2006 | 16574799 |
| germ-plasm specification and germline development in the parthenogenetic pea aphid acyrthosiphon pisum: vasa and nanos as markers. | the germarium, oocytes and embryos of the parthenogenetic viviparous pea aphid acyrthosiphon pisum are contained within a single ovariole. this species provides an excellent model for studying how maternally-inherited germ plasm is specified and how it is transferred to primordial germ cells. previous studies have shown that germ cells are first segregated at the embryonic posterior after formation of the blastoderm. we used two cross-reacting antibodies against the conserved germline markers va ... | 2006 | 16525937 |
| medicago truncatula mutants demonstrate the role of plant calcium oxalate crystals as an effective defense against chewing insects. | calcium oxalate is the most abundant insoluble mineral found in plants and its crystals have been reported in more than 200 plant families. in the barrel medic medicago truncatula gaertn., these crystals accumulate predominantly in a sheath surrounding secondary veins of leaves. mutants of m. truncatula with decreased levels of calcium oxalate crystals were used to assess the defensive role of this mineral against insects. caterpillar larvae of the beet armyworm spodoptera exigua hübner show a c ... | 2006 | 16514014 |
| predator avoidance behavior in the pea aphid: costs, frequency, and population consequences. | induced prey defenses can be costly. these costs have the potential to reduce prey survival or reproduction and, therefore, prey population growth. i estimated the potential for predators to suppress populations of pea aphids (acyrthosiphon pisum) in alfalfa fields through the induction of pea aphid predator avoidance behavior. i quantified (1) the period of non-feeding activity that follows a disturbance event, (2) the effect of frequent disturbance on aphid reproduction, and (3) the frequency ... | 2007 | 17066305 |
| molecular characterisation of a candidate gut sucrase in the pea aphid, acyrthosiphon pisum. | the hydrolysis of sucrose, the principal dietary source of carbon for aphids, is catalysed by a gut alpha-glucosidase/transglucosidase activity. an alpha-glucosidase, referred to as aps1, was identified in both a gut-specific cdna library and a sucrase-enriched membrane preparation from guts of the pea aphid acyrthosiphon pisum by a combination of genomic and proteomic techniques. aps1 contains a predicted signal peptide, and has a predicted molecular mass of 68 kda (unprocessed) or 66.4 kda (ma ... | 2007 | 17368194 |
| apvasa marks germ-cell migration in the parthenogenetic pea aphid acyrthosiphon pisum (hemiptera: aphidoidea). | in the parthenogenetic and viviparous pea aphid acyrthosiphon pisum, germline specification depends on the germ plasm localized to the posterior region of the egg chamber before the formation of the blastoderm. during blastulation, germline segregation occurs at the egg posterior, and in early gastrulation germ cells are pushed inward by the invaginating germ band. previous studies suggest that germ cells remain dorsal in the embryo in subsequent developmental stages. in fact, though, it is not ... | 2007 | 17333259 |
| analysis of heterochromatic epigenetic markers in the holocentric chromosomes of the aphid acyrthosiphon pisum. | monomethylated-k9 h3 histones (me9h3) and heterochromatin protein 1 (hp1) are reported as heterochromatin markers in several eukaryotes possessing monocentric chromosomes. in order to confirm that these epigenetic markers are evolutionarily conserved, we sequenced the hp1 cdna and verified the distribution of me9h3 histones and hp1 in the holocentric chromosomes of the aphid acyrthosiphon pisum. sequencing indicates that a. pisum hp1 cdna (called aphp1) is 1623 bp long, including a 170 bp long 5 ... | 2007 | 18004669 |
| comparison of radioimmunoassay and liquid chromatography tandem mass spectrometry for determination of juvenile hormone titers. | this paper compares the results of juvenile hormone (jh) titer determinations in two insect species, melanoplus sanguinipes, a migratory grasshopper, and acyrthosiphon pisum, the pea aphid, using a chiral-specific jh radioimmunoassay (ria) and liquid chromatography tandem mass spectrometry (lc-ms/ms), after extraction of jh with either hexane or isooctane-methanol. we compared results of jh titer determinations done on extracts of m. sanguinipes hemolymph taken from animals flown to exhaustion i ... | 2007 | 17628278 |
| deterrence and toxicity of plant saponins for the pea aphid acyrthosiphon pisum harris. | plant saponins are widely distributed among plants and have a wide range of biological properties. three alfalfa saponins - zanhic acid tridesmoside, 3glca, 28ararhaxyl medicagenic acid glycoside, and 3glca, 28ararha medicagenic acid glycoside - were tested for their settling inhibition effects on feeding behavior of the aphid acyrthosiphon pisum using the electrical penetration graph method. application of saponins to artificial diets affected the insects' probing behavior. in general, saponins ... | 2007 | 17610116 |
| ecdysteroids from serratula wolffii roots. | two new natural ecdysteroids, 20,22-didehydrotaxisterone (1) and 1-hydroxy-20,22-didehydrotaxisterone (2), were isolated from the roots of serratula wolffii. their structures were elucidated by 1d and 2d nmr spectroscopy and mass spectrometry. the biological activities of these compounds were determined via oral aphid (acyrthosiphon pisum (harris)) tests. compound 1 was inactive and compound 2 exhibited very low toxicity in the oral aphid test. the activities of these two ecdysteroids were in ag ... | 2007 | 17417908 |
| first results on the insecticidal action of saponins. | in the search for new, natural insecticides, numerous scientists are currently trying to obtain useful compound from plants. a possibly interesting class of molecules are the saponins, a group of steroidal or triterpenoidal secondary plant metabolites with divergent biological activities. in this study, we investigated the activity of saponins against living caterpillars spodoptera littoralis) and aphids (acyrthosiphon pisum) via treatment on artificial diets containing different concentrations ... | 2007 | 18399498 |
| strong heterogeneity in nucleotidic composition and codon bias in the pea aphid (acyrthosiphon pisum) shown by est-based coding genome reconstruction. | the aim of this study was to analyze patterns of nucleotidic composition and codon usage in the pea aphid genome (acyrthosiphon pisum). a collection of 60,000 expressed sequence tags (ests) in the pea aphid has been used to automatically reconstruct 5809 coding sequences (cdss), based on similarity with known proteins and on coding style recognition. reconstructions were manually checked for ribosomal proteins, leading to tentatively reconstruct the nea-complete set of this category. pea aphid c ... | 2007 | 17928936 |
| seasonal photoperiodism regulates the expression of cuticular and signalling protein genes in the pea aphid. | seasonal photoperiodism in aphids is responsible for the spectacular switch from asexual to sexual reproduction. however, little is known on the molecular and physiological mechanisms involved in reproductive mode shift through the action of day length. earlier works showed that aphid head, but not eyes, directly perceives the photoperiodic signal through the cuticle. in order to identify genes regulating the photoperiodic response, a 3321 cdna microarray developed for the pea aphid, acyrthosiph ... | 2007 | 17785197 |
| the systemic effects of juvenoids on the red firebug pyrrhocoris apterus and on the pea aphid acyrthosiphon pisum with data on life table response. | a series of juvenoid alcohols and their glycosidic derivatives (juvenogens), synthesized at the institute of organic chemistry and biochemistry in prague, commercially used juvenoids and the natural derivatives of juvabione were evaluated for their systemic juvenilizing effect on the red firebug, pyrrhocoris apterus l., and on the pea aphid, acyrthosiphon pisum harris. a life table response experiment was designed, and demographic characteristics were computed for a cohort of a. pisum following ... | 2007 | 17724791 |
| cross-species transferability of microsatellite markers from six aphid (hemiptera: aphididae) species and their use for evaluating biotypic diversity in two cereal aphids. | the abundance and distribution of microsatellites, or simple sequence repeats (ssrs) were explored in the expressed sequence tag (est) and genomic sequences of the pea aphid, acyrthosiphon pisum (harris), and the green peach aphid, myzus persicae (sulzer). a total of 108 newly developed, together with 40 published, ssr markers were investigated for their cross-species transferability among six aphid species. genetic diversity among six greenbug, schizaphis graminum (rondani) and two russian whea ... | 2007 | 17714463 |
| sex and death in the male pea aphid, acyrthosiphon pisum: the life-history effects of a wing dimorphism. | insect dispersal dimorphisms, in which both flight-capable and flightless individuals occur in the same species, are thought to reflect a balance between the benefits and costs of dispersal. fitness costs and benefits associated with wing dimorphism were investigated in the male pea aphid, acyrthosiphon pisum (harris) (hemiptera: aphididae). in one-on-one mating competitions in small arenas between winged and wingless males, the winged aphids obtained most of the matings with virgin females. in ... | 2007 | 20345312 |
| role of host nutrition in symbiont regulation: impact of dietary nitrogen on proliferation of obligate and facultative bacterial endosymbionts of the pea aphid acyrthosiphon pisum. | the impact of host nutrition on symbiont regulation in the pea aphid acyrthosiphon pisum was investigated. the population density of the obligate symbiont buchnera aphidicola positively correlated with dietary nitrogen levels. in contrast, the population density of the facultative symbiont serratia symbiotica increased in aphids reared on low-nitrogen diets, indicating distinct regulatory mechanisms in the same insect host. | 2007 | 17158610 |
| aphidbase: a database for aphid genomic resources. | aphidbase aims to (i) store recently acquired genomic resources on aphids and (ii) compare them to other insect resources as functional annotation tools. for that, the drosophila melanogaster genome has been loaded in the database using the gmod open source software for a comparison with the 17 069 pea aphid unique transcripts (contigs) and the 13 639 gene transcripts of the anopheles gambiae. links to flybase and a.gambiae entrez databases allow a rapid characterization of the putative function ... | 2007 | 17237053 |
| selective elimination of aphid endosymbionts: effects of antibiotic dose and host genotype, and fitness consequences. | multiple endosymbionts commonly coexist in the same host insects. in order to gain an understanding of the biological roles of the individual symbionts in such complex systems, experimental techniques for enabling the selective removal of a specific symbiont from the host are of great importance. by using the pea aphid-buchnera-serratia endosymbiotic system as a model, the efficacy, generality, and fitness consequences of selective elimination techniques at various antibiotic doses and under a v ... | 2007 | 17313660 |
| genetic variation in the effect of a facultative symbiont on host-plant use by pea aphids. | ecological specialisation on different host plants occurs frequently among phytophagous insects and is normally assumed to have a genetic basis. however, insects often carry microbial symbionts, which may play a role in the evolution of specialisation. the bacterium regiella insecticola is a facultative symbiont of pea aphids (acyrthosiphon pisum) where it is found most frequently in aphid clones feeding on trifolium giving rise to the hypothesis that it may improve aphid performance on this pla ... | 2007 | 17415589 |
| aphid thermal tolerance is governed by a point mutation in bacterial symbionts. | symbiosis is a ubiquitous phenomenon generating biological complexity, affecting adaptation, and expanding ecological capabilities. however, symbionts, which can be subject to genetic limitations such as clonality and genomic degradation, also impose constraints on hosts. a model of obligate symbiosis is that between aphids and the bacterium buchnera aphidicola, which supplies essential nutrients. we report a mutation in buchnera of the aphid acyrthosiphon pisum that recurs in laboratory lines a ... | 2007 | 17425405 |
| a gamma-glutamyl transpeptidase of aphidius ervi venom induces apoptosis in the ovaries of host aphids. | parasitism by the endophagous braconid aphidius ervi (hymenoptera, braconidae) has a negative impact on the reproductive activity of its host, acyrthosiphon pisum (homoptera, aphididae). the host castration is induced by the parasitoid venom and is reproduced by the injection of chromatographic fractions highly enriched with two proteins, of 18 (p18) and 36 kda (p36) in size, respectively. here we demonstrate that these bioactive proteins trigger apoptosis of the cells in the germaria and ovario ... | 2007 | 17456440 |
| antibiotics, primary symbionts and wing polyphenism in three aphid species. | the possible role of the primary buchnera symbionts in wing polyphenism is examined in three aphid species. presumptive winged aphids were fed on antibiotic-treated beans to destroy these symbionts. as previously reported, this leads to inhibited growth and low/zero fecundity. when such treatment is applied to the short-day-induced gynoparae (the winged autumn migrant) of the black bean aphid, aphis fabae, it also causes many insects to develop as wingless or winged/wingless intermediate adult f ... | 2007 | 17628287 |
| gene knockdown by rnai in the pea aphid acyrthosiphon pisum. | rna interference (rnai) is a powerful method to inhibit gene expression in a sequence specific manner. | 2007 | 17903251 |
| synthesis, insecticidal activity, and qsar of novel nitromethylene neonicotinoids with tetrahydropyridine fixed cis configuration and exo-ring ether modification. | to keep the nitro group in the cis position, a series of nitromethylene neonicotinoids containing a tetrahydropyridine ring with exo-ring ether modifications were designed and synthesized. all of the compounds were characterized and confirmed by 1h nmr, high-resolution mass spectroscopy, elemental analysis, and ir. the bioassay tests showed that some of them exhibited good insecticidal activities against pea aphids. on the basis of 10 nitromethylene derivatives, the quantitative structure-bioact ... | 2007 | 17311404 |
| [cholinesterase of the pea aphid acyrthosiphon pisi kalt]. | 2007 | 5045105 | |
| intraguild interactions of aphidophagous predators in fields: effect of coccinella septempunctata and episyrphus balteatus occurrence on aphid infested plants. | intraguild relations between beneficial insects have become a major research topic in biological pest control. in order to understand the intraguild competitions between aphidophagous populations in natural conditions, a field experiment was carried out in the experimental farm of the gembloux agricultural university. as biological control of pests involve a community of diverse natural enemies, this experiment firstly aimed to assess the aphidophagous predator diversity and abundance in green p ... | 2007 | 18399466 |
| cis-nitromethylene neonicotinoids as new nicotinic family: synthesis, structural diversity, and insecticidal evaluation of hexahydroimidazo[1,2-alpha]pyridine. | a series of neonicotinoids analogues of hexahydroimidazo[1,2-alpha]pyridine were modified at 5-, 6-, and 7-positions, and their insecticidal activities were evaluated. introducing a methyl or ethyl at 7-position increased the insecticidal activities, while other substituents decreased activities. when alkyl substituents were introduced to 7-position, the insecticidal activities against pea aphids decreased in the order methyl (7a)>ethyl (7b)>n-butyl (7e)>phenyl (7f)>n-propyl (7c)>iso-propyl (7d) ... | 2008 | 18951786 |
| rarity of males in pea aphids results in mutational decay. | when females can reproduce without males, do males become an evolutionarily weaker sex whose genes experience mutational decay? we addressed this hypothesis in aphids, whose reproduction alternates between parthenogenetic and sexual forms: over the course of a year, there can be 10 to 20 generations of asexual females but only a single, if any, generation with males. we used microarray analyses to identify male-biased, asexual female-biased, and neutral genes. interspecific comparisons reveal ac ... | 2008 | 18174433 |
| effect of seasonal abiotic conditions and field margin habitat on the activity of pandora neoaphidis inoculum on soil. | the ability of the aphid pathogenic fungus pandora neoaphidis to remain active in the absence of a resting stage through a combination of continuous infection and as conidia deposited on soil was assessed alongside the potential for planted field margins to act as a refuge for the fungus. p. neoaphidis was able to infect the pea aphid, acyrthosiphon pisum, when maintained under controlled conditions that simulated those that occur seasonally in the uk. although there was a significant inverse re ... | 2008 | 17964597 |
| population dynamics of defensive symbionts in aphids. | vertically transmitted micro-organisms can increase in frequency in host populations by providing net benefits to hosts. while laboratory studies have identified diverse beneficial effects conferred by inherited symbionts of insects, they have not explicitly examined the population dynamics of mutualist symbiont infection within populations. in the pea aphid, acyrthosiphon pisum, the inherited facultative symbiont, hamiltonella defensa, provides protection against parasitism by the wasp, aphidiu ... | 2008 | 18029301 |
| transmission efficiency of cucumber mosaic virus by aphids associated with virus epidemics in snap bean. | cucumber mosaic virus (cmv) is a major component of the virus complex that has become more pronounced in snap bean in the midwestern and northeastern united states since 2001. multiple-vector-transfer tests were done to estimate the cmv transmission efficiencies (p) of the main aphid species identified in commercial snap bean fields in new york and pennsylvania. the four most efficient vectors (p > 0.05) were aphis gossypii, a. glycines, acyrthosiphon pisum, and therioaphis trifolii, which were ... | 2008 | 18943413 |
| carbohydrate-binding activity of the type-2 ribosome-inactivating protein sna-i from elderberry (sambucus nigra) is a determining factor for its insecticidal activity. | in recent years, different classes of proteins have been reported to promote toxic effects when ingested. type-2 ribosome-inactivating proteins (rips) are a group of chimeric proteins built up of an a-chain with rna n-glycosidase activity and a b-chain with lectin activity. these proteins are thought to play a role in plant protection. sambucus nigra agglutinin i (sna-i) is a type-2 rip, isolated from the bark of elderberry (s. nigra l.). this study demonstrated the insecticidal potency of sna-i ... | 2008 | 18951590 |
| evolutionary genetics of a defensive facultative symbiont of insects: exchange of toxin-encoding bacteriophage. | the facultative endosymbiont of aphids, hamiltonella defensa, kills parasitoid wasp larvae, allowing aphid hosts to survive and reproduce. this protection may depend on toxins that are encoded by the genomes of h. defensa and of its bacteriophage (apse). strains of h. defensa vary in degree of protection conferred upon acyrthosiphon pisum (pea aphid). although h. defensa is known to undergo some horizontal transmission among aphid maternal lineages, divergence, recombination, and population stru ... | 2008 | 18179430 |
| insecticidal activity of a basement membrane-degrading protease against heliothis virescens (fabricius) and acyrthosiphon pisum (harris). | scathl is a cathepsin l-like cysteine protease derived from the flesh fly sarcophaga peregrina that functions in basement membrane (bm) remodeling during insect development. a recombinant baculovirus expressing scathl (acmlf9.scathl) kills larvae of the tobacco budworm, heliothis virescens, significantly faster than the wild-type virus. here, we show that the occurrence of larval melanization prior to death was closely associated with the onset of high cysteine protease activity of scathl in the ... | 2008 | 18395222 |
| [effects of cutting on the population dynamics of main insect pests on alfalfa]. | a systematic investigation was made on the effects of cutting on the population dynamics of main insect pests on alfalfa in dingxi of gansu province. the results showed that the effects of cutting varied significantly with the kinds of insect pests. the seasonal average population densities of therioaphis trifolii, acyrthosiphon pisum and thrips decreased significantly and maintained at a low level under the first cutting in early june, but less variation was observed under the second cutting in ... | 2008 | 18533546 |
| complex interactions between a plant pathogen and insect parasitoid via the shared vector-host: consequences for host plant infection. | plant viruses modify the development of their aphid vectors by inducing physiological changes in the shared host plant. the performance of hymenopterous parasitoids exploiting these aphids can also be modified by the presence of the plant pathogen. we used laboratory and glasshouse microcosms containing beans (vicia faba) as the host plant to examine the interactions between a plant virus (pea enation mosaic virus; pemv) and a hymenopterous parasitoid (aphidius ervi) that share the aphid vector/ ... | 2008 | 18566836 |
| the insecticidal activity of recombinant garlic lectins towards aphids. | the heterodimeric and homodimeric garlic lectins asai and asaii were produced as recombinant proteins in the yeast pichia pastoris. the proteins were purified as functional dimeric lectins, but underwent post-translational proteolysis. recombinant asaii was a single homogenous polypeptide which had undergone c-terminal processing similar to that occurring in planta. the recombinant asai was glycosylated and subject to variable and heterogenous proteolysis. both lectins showed insecticidal effect ... | 2008 | 18707000 |
| in silico analyses of peptide paracrines/hormones in aphidoidea. | the aphidoidea is an insect superfamily comprising most of the known aphid species. while small in size, these animals are of considerable economic importance as many members of this taxon are serious agricultural pests, inflicting physical damage upon crop plants and serving as vectors in the transmission of viral plant diseases. in terms of identifying the paracrines/hormones used to modulate behavior, particularly peptides, members of the aphidoidea have largely been ignored, as it is not tra ... | 2008 | 18725225 |
| evaluation of artificial diets for rearing aphis glycines (hemiptera: aphididae). | artificial aphid diets have been previously developed for the pea aphid, acyrthosiphon pisum (harris), and the green peach aphid, myzus persicae (sulzer). the ability to rear aphids on an artificial diet allows for selectively adding or subtracting compounds from an aphid's food source to determine the effect on fecundity and longevity. five diets previously developed for the green peach aphid and the pea aphid were tested for their suitability for rearing soybean aphid, aphis glycines matsumura ... | 2008 | 18767731 |
| do plant viruses facilitate their aphid vectors by inducing symptoms that alter behavior and performance? | aphids can respond both positively and negatively to virus-induced modifications of the shared host plant. it can be speculated that viruses dependent on aphids for their transmission might evolve to induce changes in the host plant that attract aphids and improve their performance, subsequently enhancing the success of the pathogen itself. we studied how pea aphids [acyrthosiphon pisum (harris)] responded to infection of tic beans (vicia faba l.) by three viruses with varying degrees of depende ... | 2008 | 19161702 |
| identification of aphid salivary proteins: a proteomic investigation of myzus persicae. | the role of insect saliva in the first contact between an insect and a plant is crucial during feeding. some elicitors, particularly in insect regurgitants, have been identified as inducing plant defence reactions. here, we focused on the salivary proteome of the green peach aphid, myzus persicae. proteins were either directly in-solution digested or were separated by 2d sds-page before trypsin digestion. resulting peptides were then identified by mass spectrometry coupled with database investig ... | 2008 | 18353105 |
| real-time analysis of alarm pheromone emission by the pea aphid (acyrthosiphon pisum) under predation. | upon attack by predators or parasitoids, aphids emit volatile chemical alarm signals that warn other aphids of a potential risk of predation. release rate of the major constituent of the alarm pheromone in pea aphids (acyrthosiphon pisum), (e)-b-farnesene (ebf), was measured for all nymphal and the adult stage as aphids were attacked individually by lacewing (chrysoperla carnae) larvae. volatilization of ebf from aphids under attack was quantified continuously for 60 min at 2-min intervals with ... | 2008 | 18092189 |
| the influence of natural enemies on wing induction in aphis fabae and megoura viciae (hemiptera: aphididae). | previous studies have shown that the aphid species, aphis fabae scopoli and megoura viciae buckton, do not produce winged offspring in the presence of natural enemies, in contrast to results for the pea aphid (acyrthosiphon pisum (harris)) and the cotton aphid (aphis gossypii glover); but these studies did not involve exposing aphids directly to natural enemies. we exposed colonies of both a. fabae and m. viciae to foraging lacewing (chrysoperla carnea (stephens)) larvae and found that the preda ... | 2008 | 18076776 |
| sex versus parthenogenesis: a transcriptomic approach of photoperiod response in the model aphid acyrthosiphon pisum (hemiptera: aphididae). | most aphids develop a cyclic parthenogenesis life-cycle. after several generations of viviparous parthenogenetic females, it follows a single annual generation of sexual individuals, usually in autumn, that mate and lay the sexual eggs. shortening of photoperiod at the end of the summer is a key factor inducing the sexual response. with the survey here reported we aimed at identifying a collection of candidate genes to participate at some point in the cascade of events that lead to the sexual ph ... | 2008 | 18065167 |
| host range expansion of an introduced insect pest through multiple colonizations of specialized clones. | asexuality confers demographic advantages to invasive taxa, but generally limits adaptive potential for colonizing of new habitats. therefore, pre-existing adaptations and habitat tolerance are essential in the success of asexual invaders. we investigated these key factors of invasiveness by assessing reproductive modes and host-plant adaptations in the pea aphid, acyrthosiphon pisum, a pest recently introduced into chile. the pea aphid encompasses lineages differing in their reproductive mode, ... | 2008 | 19140984 |
| effect of wild flowers on oviposition of hippodamia variegata (coleoptera: coccinellidae) in the laboratory. | marginal vegetation in crops is very important for natural enemies and their pest control capacity. the effects of brassica nigra l. (brassicaceae), daucus carota l. (apiaceae), and sonchus oleraceous l. (asteraceae) flowers as supplemental food on the number of eggs laid during 7 d and on the preoviposition time in hippodamia variegata (goeze, 1777) were studied in the laboratory under conditions of several densities of acyrthosiphon pisum (harris, 1776). the results show the presence of flower ... | 2008 | 19133458 |
| wounding-mediated gene expression and accelerated viviparous reproduction of the pea aphid acyrthosiphon pisum. | most insects mount a potent antimicrobial defence upon contact with microbes or microbe-associated pattern molecules. using a combined set of methods for analysis of insect innate immunity, we report here that piercing of the pea aphid acyrthosiphon pisum with a bacteria-contaminated needle elicits lysozyme-like activity in the haemolymph but no detectable activities against live bacteria. confirming these results, we found no homologues of known antimicrobial peptides in our cdna library genera ... | 2008 | 18823444 |
| do aphid colonies amplify their emission of alarm pheromone? | when aphids are attacked by natural enemies, they emit alarm pheromone to alert conspecifics. for most aphids tested, (e)-beta-farnesene (ebf) is the main, or only, constituent of the alarm pheromone. in response to alarm pheromone, alerted aphids drop off the plant, walk away, or attempt to elude predators. however, under natural conditions, ebf concentration might be low due to the low amounts emitted, to rapid air movement, or to oxidative degradation. to ensure that conspecifics are warned, ... | 2008 | 18704588 |