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predation determines different selective pressure on pea aphid host races in a complex agricultural mosaic.field assessments were conducted to examine the interplay between host plant and predation in complex agricultural mosaic on pea aphid clover and alfalfa races. in one experiment, we examined the relative fitness on clover race (cr) and alfalfa race (ar) pea aphids on broad bean, red clover and alfalfa alone. but because clover is typically grown in a more complex agricultural mosaic with alfalfa and broad bean, a second experiment was conducted to assess the fitness consequences under predation ...201323409081
the pea aphid (acyrthosiphon pisum) genome encodes two divergent early developmental programs.the pea aphid (acyrthosiphon pisum) can reproduce either sexually or asexually (parthenogenetically), giving rise, in each case, to almost identical adults. these two modes of reproduction are accompanied by differences in ovarian morphology and the developmental environment of the offspring, with sexual forms producing eggs that are laid, whereas asexual development occurs within the mother. here we examine the effect each mode of reproduction has on the expression of key maternal and axis patt ...201323416037
comparative genomic analysis and evolution of family-b g protein-coupled receptors from six model insect species.family-b g protein-coupled receptors (gpcr-bs) play vital roles in many biological processes, including growth, development and reproduction. however, the evolution and function of gpcr-bs have been poorly understood in insects. we have identified 87 gpcr-bs from six model insect species, 20 from tribolium castaneum, 9 from apis mellifera, 11 from bombyx mori, 9 from acyrthosiphon pisum, 14 from anopheles gambiae and 24 from drosophila melanogaster. 22 of them were reported in this study for the ...201323428791
canonical terminal patterning is an evolutionary novelty.patterning of the terminal regions of the drosophila embryo is achieved by an exquisitely regulated signal that passes between the follicle cells of the ovary, and the developing embryo. this pathway, however, is missing or modified in other insects. here we trace the evolution of this pathway by examining the origins and expression of its components. the three core components of this pathway: trunk, torso and torso-like have different evolutionary histories and have been assembled step-wise to ...201323438815
proteomic profiling of cereal aphid saliva reveals both ubiquitous and adaptive secreted proteins.the secreted salivary proteins from two cereal aphid species, sitobion avenae and metopolophium dirhodum, were collected from artificial diets and analysed by tandem mass spectrometry. protein identification was performed by searching ms data against the official protein set from the current pea aphid (acyrthosiphon pisum) genome assembly and revealed 12 and 7 proteins in the saliva of s. avenae and m. dirhodum, respectively. when combined with a comparable dataset from a. pisum, only three indi ...201323460852
characterization of non-ltr retrotransposable tras elements in the aphids acyrthosiphon pisum and myzus persicae (aphididae, hemiptera).a non-ltr tras retrotransposon (identified as trasap1) has been amplified in the pea aphid acyrthosiphon pisum and its presence has been assessed also in the peach potato aphid myzus persicae. this tras element possesses 2 overlapping orfs (a gag-orf1 and a pol-orf2 containing the reverse transcriptase and the endonuclease domains) that show a similarity ranging from 40% to 48% to proteins coded by other tras elements identified in insects (including the beetle tribolium castaneum and the moth b ...201323530141
carotenoids in unexpected places: gall midges, lateral gene transfer, and carotenoid biosynthesis in animals.carotenoids are conjugated isoprenoid molecules with many important physiological functions in organisms, including roles in photosynthesis, oxidative stress reduction, vision, diapause, photoperiodism, and immunity. until recently, it was believed that only plants, microorganisms, and fungi were capable of synthesizing carotenoids and that animals acquired them from their diet, but recent studies have demonstrated that two arthropods (pea aphid and spider mite) possess a pair of genes homologou ...201323542649
the pea aphid uses a version of the terminal system during oviparous, but not viviparous, development.in most species of aphid, female nymphs develop into either sexual or asexual adults depending on the length of the photoperiod to which their mothers were exposed. the progeny of these sexual and asexual females, in turn, develop in dramatically different ways. the fertilized oocytes of sexual females begin embryogenesis after being deposited on leaves (oviparous development) while the oocytes of asexual females complete embryogenesis within the mother (viviparous development). compared with ov ...201323552511
survival to parasitoids in an insect hosting defensive symbionts: a multivariate approach to polymorphic traits affecting host use by its natural enemy.insect parasitoids and their insect hosts represent a wide range of parasitic trophic relations that can be used to understand the evolution of biotic diversity on earth. testing theories of coevolution between hosts and parasites is based on factors directly involved in host susceptibility and parasitoid virulence. we used controlled encounters with potential hosts of the aphidius ervi wasp to elucidate behavioral and other phenotypic traits of host acyrthosiphon pisum that most contribute to s ...201323565269
oxidative stress in pea seedling leaves in response to acyrthosiphon pisum infestation.in this study we examined whether and to what extent oxidative stress is induced in seedling leaves of pisum sativum l. cv. cysterski in response to pea aphid (acyrthosiphon pisum harris) infestation. a. pisum caused oxidative stress conditions in pea leaves through enhanced production of the reactive oxygen species (ros) hydrogen peroxide (h2o2) and superoxide anion radical (o2(·-)). early, strong generation of h2o2 was observed at 24h in aphid-infested leaves. the highest level of h2o2 at this ...201323566717
tyrosine pathway regulation is host-mediated in the pea aphid symbiosis during late embryonic and early larval development.nutritional symbioses play a central role in insects' adaptation to specialized diets and in their evolutionary success. the obligatory symbiosis between the pea aphid, acyrthosiphon pisum, and the bacterium, buchnera aphidicola, is no exception as it enables this important agricultural pest insect to develop on a diet exclusively based on plant phloem sap. the symbiotic bacteria provide the host with essential amino acids lacking in its diet but necessary for the rapid embryonic growth seen in ...201323575215
parasitoid wasps influence where aphids die via an interspecific indirect genetic effect.host-parasite interactions are a key paradigm for understanding the process of coevolution. central to coevolution is how genetic variation in interacting species allows parasites to evolve manipulative strategies. however, genetic variation in the parasite may also be associated with host phenotype changes, thereby changing the selection on both species. for instance, parasites often induce changes in the behaviour of their host to maximize their own fitness, yet the quantitative genetic basis ...201323576776
widespread selection across coding and noncoding dna in the pea aphid genome.genome-wide patterns of diversity and selection are critical measures for understanding how evolution has shaped the genome. yet, these population genomic estimates are available for only a limited number of model organisms. here we focus on the population genomics of the pea aphid (acyrthosiphon pisum). the pea aphid is an emerging model system that exhibits a range of intriguing biological traits not present in classic model systems. we performed low-coverage genome resequencing of 21 clonal p ...201323589520
jumping-ship can have its costs: implications of predation and host plant species for the maintenance of pea aphid (acyrthosiphon pisum harris) colour polymorphism.the interplay between the host plant of an insect herbivore and an insect predator (here two-spot ladybird beetles; adalia bipunctata (l).; coleoptera: coccinellidae), feeding upon such a herbivore was examined in the laboratory as factors possibly determining the differential abundance and success of green and red host races of pea aphid, acyrthosiphon pisum harris. the experiment comprised three treatments: two host plants (bean and clover), two treatment levels (control and predation) and thr ...201323601915
retargeting of the bacillus thuringiensis toxin cyt2aa against hemipteran insect pests.although transgenic crops expressing bacillus thuringiensis (bt) toxins have been used successfully for management of lepidopteran and coleopteran pest species, the sap-sucking insects (hemiptera) are not particularly susceptible to bt toxins. to overcome this limitation, we demonstrate that addition of a short peptide sequence selected for binding to the gut of the targeted pest species serves to increase toxicity against said pest. insertion of a 12-aa pea aphid gut-binding peptide by adding t ...201323650347
aphicidal efficacy of scorpion- and spider-derived neurotoxins.insect-specific neurotoxins that act within the insect hemocoel (body cavity) represent an untapped resource for insect pest management. on the basis of recent advances made in development of appropriate delivery systems for transport of these toxins from the insect gut, across the gut epithelium to their target site, we screened neurotoxins derived from scorpion or spider venom for efficacy against the pea aphid, acyrthosiphon pisum, and the green peach aphid, myzus persicae. toxins were select ...201323651761
noncanonical expression of caudal during early embryogenesis in the pea aphid acyrthosiphon pisum: maternal cad-driven posterior development is not conserved.previously we identified anterior localization of hunchback (aphb) mrna in oocytes and early embryos of the parthenogenetic and viviparous pea aphid acyrthosiphon pisum, suggesting that the breaking of anterior asymmetry in the oocytes leads to the formation of the anterior axis in embryos. in order to study posterior development in the asexual pea aphid, we cloned and analysed the developmental expression of caudal (apcad), a posterior gene highly conserved in many animal phyla. we found that t ...201323683148
modulation of aphid alarm pheromone emission of pea aphid prey by predators.recent studies on animal alarm signaling have shown that alarm calls generally are not uniform, but may vary depending on the type and intensity of threat. while alarm call variability has been studied intensively in birds and mammals, little is known about such variation in insects. we investigated variability in alarm signaling in aphids, group-living insect herbivores. under attack, aphids release droplets containing a volatile alarm pheromone, (e)-β-farnesene (ebf), that induces specific esc ...201323686467
pea aphid promotes amino acid metabolism both in medicago truncatula and bacteriocytes to favor aphid population growth under elevated co2.rising atmospheric co(2) levels can dilute the nitrogen (n) resource in plant tissue, which is disadvantageous to many herbivorous insects. aphids appear to be an exception that warrants further study. the effects of elevated co(2) (750 ppm vs. 390 ppm) were evaluated on n assimilation and transamination by two medicago truncatula genotypes, a n-fixing-deficient mutant (dnf1) and its wild-type control (jemalong), with and without pea aphid (acyrthosiphon pisum) infestation. elevated co(2) increa ...201323686968
environment exploration and colonization behavior of the pea aphid associated with the expression of the foraging gene.aphids respond to specific environmental cues by producing alternative morphs, a phenomenon called polyphenism, but also by modulating their individual behavior even within the same morph. this complex plasticity allows a rapid adaptation of individuals to fluctuating environmental conditions, but the underlying genetic and molecular mechanisms remain largely unknown. the foraging gene is known to be associated with behavior in various species and has been shown to mediate the behavioral shift i ...201323734236
thiamine treatments alleviate aphid infestations in barley and pea.treatment of plants with thiamine (vitamin b1) has before been shown to activate plant defence against microorganisms. here, we have studied the effects of thiamine treatments of plants on aphid reproduction and behaviour. the work was mainly carried out with bird cherry-oat aphid (rhopalosiphum padi l.) on barley (hordeum vulgare l.). aphid population growth and aphid acceptance on plants grown from seeds soaked in a 150μm thiamine solution were reduced to ca. 60% of that on control plants. r. ...201323787153
identification of g protein-coupled receptors in the pea aphid, acyrthosiphon pisum.gpcrs play crucial roles in the growth, development and reproduction of organisms. in insects, a large number of gpcrs have been reported for holometabola but not hemimetabola. the recently sequenced pea aphid genome provides us with the opportunity to analyze the evolution and potential functions of gpcrs in hemimetabola. 82 gpcrs were identified from the representative model hemimetabolous insect acyrthosiphon pisum, 37 of which have ests evidence, and 73 are annotated for the first time. a st ...201323792713
does phloem-based resistance to aphid feeding affect host-plant acceptance for reproduction? parturition of the pea aphid, acyrthosiphon pisum, on two near-isogenic lines of medicago truncatula.probing behaviour (prior to parturition) and parturition of two clones (ps01 and n116) of the pea aphid, acyrthosiphon pisum on two genotypes (near-isogenic lines (nils)) (q174_5.13 and q174_9.10) of medicago truncatula were investigated using electrical penetration graph (epg) coupled with simultaneous visual monitoring for parturition. line q174_5.13 has been reported to show a phloem-based resistance to feeding in the clone ps01 but to be susceptible to the clone n116, whereas q174_9.10 has s ...201323823797
larval performance and kill rate of convergent ladybird beetles, hippodamia convergens, on black bean aphids, aphis fabae, and pea aphids, acyrthosiphon pisum.generalist predator guilds play a prominent role in structuring insect communities and can contribute to limiting population sizes of insect pest species. a consequence of dietary breadth, particularly in predatory insects, is the inclusion of low-quality, or even toxic, prey items in the predator's diet. consumption of low-quality prey items reduces growth, development, and survival of predator larvae, thereby reducing the population sizes of generalist predators. the objective of this paper wa ...201323909291
identification, characterization and analysis of expression of genes encoding arylalkylamine n-acetyltransferases in the pea aphid acyrthosiphon pisum.most organisms exhibit some kind of rhythmicity in their behaviour and/or physiology as an adaptation to the cyclical movements of the earth. in addition to circadian rhythms, many organisms have an annual rhythmicity in certain activities, such as reproduction, migration or induction of diapause. current knowledge of the molecular basis controlling seasonal rhythmicity, especially in insects, is scarce. one element that seems to play an essential role in the maintenance of both circadian and se ...201323919438
masculinization of the x chromosome in the pea aphid.evolutionary theory predicts that sexually antagonistic mutations accumulate differentially on the x chromosome and autosomes in species with an xy sex-determination system, with effects (masculinization or feminization of the x) depending on the dominance of mutations. organisms with alternative modes of inheritance of sex chromosomes offer interesting opportunities for studying sexual conflicts and their resolution, because expectations for the preferred genomic location of sexually antagonist ...201323950732
horizontally transmitted symbionts and host colonization of ecological niches.facultative or "secondary" symbionts are common in eukaryotes, particularly insects. while not essential for host survival, they often provide significant fitness benefits. it has been hypothesized that secondary symbionts form a "horizontal gene pool" shuttling adaptive genes among host lineages in an analogous manner to plasmids and other mobile genetic elements in bacteria. however, we do not know whether the distributions of symbionts across host populations reflect random acquisitions follo ...201323993843
exposure to bacterial signals does not alter pea aphids' survival upon a second challenge or investment in production of winged offspring.pea aphids have an obligate nutritional symbiosis with the bacteria buchneraaphidicola and frequently also harbor one or more facultative symbionts. aphids are also susceptible to bacterial pathogen infections, and it has been suggested that aphids have a limited immune response towards such pathogen infections compared to other, more well-studied insects. however, aphids do possess at least some of the genes known to be involved in bacterial immune responses in other insects, and immune-compete ...201324009760
elevated co2 decreases the response of the ethylene signaling pathway in medicago truncatula and increases the abundance of the pea aphid.the performance of herbivorous insects is greatly affected by plant nutritional quality and resistance, which are likely to be altered by rising concentrations of atmospheric co2 . we previously reported that elevated co2 enhanced biological nitrogen (n) fixation of medicago truncatula, which could result in an increased supply of amino acids to the pea aphid (acyrthosiphon pisum). the current study examined the n nutritional quality and aphid resistance of sickle, an ethylene-insensitive mutant ...201424015892
monitoring of aphid flight activities in seed potato crops in serbia.aphid flight activities in seed potato fields have been studied by the yellow water traps. it is a good method for monitoring aphids as vectors of viruses, but this study also showed it is a suitable method for insect-diversity research. during the four-year studies, over 11.500 specimens were collected and a total of 107 different taxa of aphids were identified. the most abundant species were polyphagous species, such as: acyrthosiphon pisum (haris), aphis fabae scopoli, aphis gossypii gloveran ...201324039529
is ecological speciation a major trend in aphids? insights from a molecular phylogeny of the conifer-feeding genus cinara.in the past decade ecological speciation has been recognized as having an important role in the diversification of plant-feeding insects. aphids are host-specialised phytophagous insects that mate on their host plants and, as such, they are prone to experience reproductive isolation linked with host plant association that could ultimately lead to species formation. the generality of such a scenario remains to be tested through macroevolutionary studies. to explore the prevalence of host-driven s ...201324044736
identification and expression profiling of odorant binding proteins and chemosensory proteins between two wingless morphs and a winged morph of the cotton aphid aphis gossypii glover.insects interact with their environment and respond to the changes in host plant conditions using semiochemicals. such ecological interactions are facilitated by the olfactory sensilla and the use of olfactory recognition proteins. the cotton aphid aphis gossypii can change its phenotype in response to ecological conditions. they reproduce mainly as wingless asexual morphs but develop wings to find mates or new plant hosts under the influence of environmental factors such as temperature, plant n ...201324073197
proteomic investigation of aphid honeydew reveals an unexpected diversity of proteins.aphids feed on the phloem sap of plants, and are the most common honeydew-producing insects. while aphid honeydew is primarily considered to comprise sugars and amino acids, its protein diversity has yet to be documented. here, we report on the investigation of the honeydew proteome from the pea aphid acyrthosiphon pisum. using a two-dimensional differential in-gel electrophoresis (2d-dige) approach, more than 140 spots were isolated, demonstrating that aphid honeydew also represents a diverse s ...201324086359
to feed or not to feed: plant factors located in the epidermis, mesophyll, and sieve elements influence pea aphid's ability to feed on legume species.the pea aphid (acyrthosiphon pisum harris), a legume specialist, encompasses at least 11 genetically distinct sympatric host races. each host race shows a preference for a certain legume species. six pea aphid clones from three host races were used to localize plant factors influencing aphid probing and feeding behavior on four legume species. aphid performance was tested by measuring survival and growth. the location of plant factors influencing aphid probing and feeding was determined using th ...201324098691
protection against a fungal pathogen conferred by the aphid facultative endosymbionts rickettsia and spiroplasma is expressed in multiple host genotypes and species and is not influenced by co-infection with another symbiont.many insects harbour facultative endosymbiotic bacteria, often more than one type at a time. these symbionts can have major effects on their hosts' biology, which may be modulated by the presence of other symbiont species and by the host's genetic background. we investigated these effects by transferring two sets of facultative endosymbionts (one hamiltonella and rickettsia, the other hamiltonella and spiroplasma) from naturally double-infected pea aphid hosts into five novel host genotypes of t ...201324118386
avoidance of intraguild predation leads to a long-term positive trait-mediated indirect effect in an insect community.intraguild predation among natural enemies is common in food webs with insect herbivores at their base. though intraguild predation may be reciprocal, typically one species suffers more than the other and frequently exhibits behavioural strategies to lessen these effects. how such short-term behaviours influence population dynamics over several generations has been little studied. we worked with a model insect community consisting of two species of aphid feeding on different host plants (acyrtho ...201424122178
effects of parasitism on aphid nutritional and protective symbioses.insects often carry heritable symbionts that negotiate interactions with food plants or natural enemies. all pea aphids, acyrthosiphon pisum, require infection with the nutritional symbiont buchnera, and many are also infected with hamiltonella, which protects against the parasitoid aphidius ervi. hamiltonella-based protection requires bacteriophages called apses with protection levels varying by strain and associated apse. endoparasitoids, including a. ervi, may benefit from protecting the nutr ...201424152321
real-time monitoring of (e)-β-farnesene emission in colonies of the pea aphid, acyrthosiphon pisum, under lacewing and ladybird predation.aphids (homoptera) are constantly under attack by a variety of predators and parasitoids. upon attack, most aphids release alarm pheromone that induces escape behavior in other colony members, such as dropping off the host plant. in the pea aphid, acyrthosiphon pisum harris (aphididae), the only component of this alarm pheromone is the sesquiterpene (e)-β-farnesene (ebf). ebf is thought to act as a kairomone by attracting various species of parasitoids and predators including lacewings and ladyb ...201324158268
cannibalism in the pea aphid, acyrthosiphon pisum.previous observations of cannibalism have been made in the aphid acyrthosiphon pisum (l.): this article seeks to quantify factors contributing to such behaviors. we observed and quantified the responses of a number of clones and life stages to varying levels of starvation, in the form of increasingly desiccated vica faba l. plants (receiving 50, 25, or 10 ml every second day) or a complete absence of host plant. we found that, while the longest incidences of cannibalism are carried out by juveni ...201424167148
two developmental switch points for the wing polymorphisms in the pea aphid acyrthosiphon pisum.in many insect taxa, wing polymorphism is known to be a consequence of tradeoffs between flight and other life-history traits. the pea aphid acyrthosiphon pisum exhibits various morphs with or without wings associated with their complex life cycle including wing polyphenism in viviparous females, genetic wing polymorphism in males, and a monomorphic wingless phenotype in oviparous females and fundatrices. while wing differentiation has been investigated in some detail in viviparous females and m ...201324175956
the combined effects of bacterial symbionts and aging on life history traits in the pea aphid, acyrthosiphon pisum.while many endosymbionts have beneficial effects on hosts under specific ecological conditions, there can also be associated costs. in order to maximize their own fitness, hosts must facilitate symbiont persistence while preventing symbiont exploitation of resources, which may require tight regulation of symbiont populations. as a host ages, the ability to invest in such mechanisms may lessen or be traded off with demands of other life history traits, such as survival and reproduction. using the ...201424185857
phenotypic effect of "candidatus rickettsiella viridis," a facultative symbiont of the pea aphid (acyrthosiphon pisum), and its interaction with a coexisting symbiont.a gammaproteobacterial facultative symbiont of the genus rickettsiella was recently identified in the pea aphid, acyrthosiphon pisum. infection with this symbiont altered the color of the aphid body from red to green, potentially affecting the host's ecological characteristics, such as attractiveness to different natural enemies. in european populations of a. pisum, the majority of rickettsiella-infected aphids also harbor another facultative symbiont, of the genus hamiltonella. we investigated ...201424212575
hunchback is required for abdominal identity suppression and germband growth in the parthenogenetic embryogenesis of the pea aphid, acyrthosiphon pisum.aphid, a short germband insect, displays an embryogenesis different from that of long germband insect species. furthermore, the development of its parthenogenetic and viviparous embryo is different from that of the embryo resulting from sexual reproduction. to better understand the genetic regulation of this type of embryogenesis, the functions of hunchback in asexual acyrthosiphon pisum were investigated by parental rnai. microinjection of aphb double-stranded rna yielded several defective phen ...201324222010
relative importance of semiochemicals from first and second trophic levels in host foraging behavior ofaphidius ervi.the responses of femaleaphidius ervi to odors from a host food plant (vicia faba), host aphids (acyrthosiphon pisum), nonhost aphids (aphis fabae), and aphid-plant complexes were investigated in a specially designed wind tunnel and a y-tube olfactometer. in single-target (no-choice) and two-target (dual-choice) experiments, plant volatiles played a crucial role in the host foraging behavior ofa. ervi. the odor from thea. pisum-plant complex elicited the strongest responses bya. ervi females, fol ...199624226473
variation in aphid alarm pheromone content among glandular and eglandular-hairedmedicago accessions.pea (acyrthosiphon pisum harris) and blue alfalfa aphid (a. kondoi shinji) deterrency in alfalfa (medicago saliva l.) may result from incorporating higher levels of the aphid alarm pheromone,(e)-β-farnesene relative to(e)-β-caryophyllene. we evaluated five eglandular and two glandular-haired alfalfa accessions for differences in(e)-β-farnesene and(e)-β-caryophyllene content under glasshouse conditions using supercritical fluid extraction and gas chromatography. in addition, pea and blue alfalfa ...199624226476
worldwide populations of the aphid aphis craccivora are infected with diverse facultative bacterial symbionts.facultative bacterial endosymbionts can play an important role in the evolutionary trajectory of their hosts. aphids (hemiptera: aphididae) are infected with a wide variety of facultative endosymbionts that can confer ecologically relevant traits, which in turn may drive microevolutionary processes in a dynamic selective environment. however, relatively little is known about how symbiont diversity is structured in most aphid species. here, we investigate facultative symbiont species richness and ...201424233285
quantification of electroantennogram responses of the primary rhinaria ofacyrthosiphon pisum (harris) to c4-c 8 primary alcohols and aldehydes.electroantennograms (eags) of the distal and proximal primary rhinaria (dpr and ppr, respectively) were recorded from excised antennae of alate virginoparous pea aphids,acyrthosiphon pisum (harris) (homoptera: aphididae). primary unsaturated alcohols and aldehydes with varying carbon length (c4-c8) were used as volatile stimuli. eags were recorded for a series of source concentrations from the dpr and ppr separately through the use of sectional electroantennography. a logistic equation was fitte ...199424242205
effects of elevated temperature and co2 on aboveground-belowground systems: a case study with plants, their mutualistic bacteria and root/shoot herbivores.interactions between above- and belowground herbivores have been prominent in the field of aboveground-belowground ecology from the outset, although little is known about how climate change affects these organisms when they share the same plant. additionally, the interactive effects of multiple factors associated with climate change such as elevated temperature (et) and elevated atmospheric carbon dioxide (eco2) are untested. we investigated how et and eco2 affected larval development of the luc ...201324273544
salivary proteins of plant-feeding hemipteroids - implication in phytophagy.many hemipteroids are major pests and vectors of microbial pathogens, infecting crops. saliva of the hemipteroids is critical in enabling them to be voracious feeders on plants, including the economically important ones. a plethora of hemipteroid salivary enzymes is known to inflict stress in plants, either by degrading the plant tissue or by affecting their normal metabolism. hemipteroids utilize one of the following three strategies of feeding behaviour: salivary sheath feeding, osmotic-pump f ...201424280006
feeding deterrency of some 4-hydroxycoumarins and related compounds: relationship to host-plant resistance of alfalfa towards pea aphid (acyrthosiphon pisum).a series of 3-acyl-4-hydroxycoumarins, structurally related to dicoumarol, as well as several alfalfa constituents including coumestrol were tested for their feeding deterrency towards the pea aphid. feeding deterrency of the 3-acyl-4-hydroxycoumarins decreased as the size of the 3-acyl group increased.198724302057
differential inhibition by castanospermine of various insect disaccharidases.the indolizidine alkaloid, castanospermine (1,6,7,8-tetrahydroxy-octahydroindolizidine-a stereochemical mimic of glucose found in the australian legumecastanospermum australe), differentially inhibited cellobiose, lactose, maltose, sucrose, and trehalose hydrolyzing enzymes from a broad taxonomic spectrum of insects (19 species from 12 different families). it was a potent inhibitor of cellobiase activity of all insects tested (50% inhibition at <3.2 × 10(-5) m castanospermine). with one exceptio ...198724302343
feeding deterrency of some pyrrolizidine, indolizidine, and quinolizidine alkaloids towards pea aphid (acyrthosiphon pisum) and evidence for phloem transport of indolizidine alkaloid swainsonine.the feeding deterrency of a series of pyrrolizidine, indolizidine, and quinolizidine alkaloids and selected derivatives was measured against the pea aphid (acyrthosiphon pisum harris). the indolizidine alkaloid, castanospermine, was intensely active (ed50, 20 ppm) as were the quinolizidine alkaloids, but only modest feeding deterrency was observed with most of the pyrrolizidine alkaloids tested. the insect survival rate of aphids on a castanospermine-supplemented diet over 24 hr was also very lo ...198524310329
toxin delivery by the coat protein of an aphid-vectored plant virus provides plant resistance to aphids.the sap-sucking insects (order hemiptera), including aphids, planthoppers, whiteflies and stink bugs, present one of the greatest challenges for pest management in global agriculture. insect neurotoxins offer an alternative to chemical insecticides for controlling these pests, but require delivery into the insect hemocoel. here we use the coat protein of a luteovirus, an aphid-vectored plant virus, to deliver a spider-derived, insect-specific toxin that acts within the hemocoel. the luteovirid c ...201424316580
characterization of the distal-less gene homologue, nldll, in the brown planthopper, nilaparvata lugens (stål).the brown planthopper, nilaparvata lugens (stål), is a globally devastating insect pest of rice, particularly in eastern asia. distal-less or dll is a highly conserved and well studied transcription factor required for limb formation in invertebrates and vertebrates. we have identified a homologue of this gene, nldll, and demonstrated that it is expressed in all life stages of n. lugens, particularly in adult brachypterous females. when we compared between specific adult tissues it was expressed ...201424321689
the bacterial communities in plant phloem-sap-feeding insects.the resident microbiota of animals represents an important contribution to the global microbial diversity, but it is poorly known in many animals. this study investigated the bacterial diversity in plant phloem-sap-feeding whiteflies, aphids and psyllids by pyrosequencing bacterial 16s rrna gene amplicons. after correction for sequencing error, just 3-7 bacterial operational taxonomic units were recovered from each insect sample sequenced to sufficient depth for saturation of rarefaction curves. ...201424350573
comparative analysis of genome sequences from four strains of the buchnera aphidicola mp endosymbion of the green peach aphid, myzus persicae.myzus persicae, the green peach aphid, is a polyphagous herbivore that feeds from hundreds of species of mostly dicot crop plants. like other phloem-feeding aphids, m. persicae rely on the endosymbiotic bacterium, buchnera aphidicola (buchnera mp), for biosynthesis of essential amino acids and other nutrients that are not sufficiently abundant in their phloem sap diet. tobacco-specialized m. persicae are typically red and somewhat distinct from other lineages of this species. to determine whethe ...201324365332
aphid amino acid transporter regulates glutamine supply to intracellular bacterial symbionts.endosymbiotic associations have played a major role in evolution. however, the molecular basis for the biochemical interdependence of these associations remains poorly understood. the aphid-buchnera endosymbiosis provides a powerful system to elucidate how these symbioses are regulated. in aphids, the supply of essential amino acids depends on an ancient nutritional symbiotic association with the gamma-proteobacterium buchnera aphidicola. buchnera cells are densely packed in specialized aphid ba ...201324367072
social aggregation in pea aphids: experiment and random walk modeling.from bird flocks to fish schools and ungulate herds to insect swarms, social biological aggregations are found across the natural world. an ongoing challenge in the mathematical modeling of aggregations is to strengthen the connection between models and biological data by quantifying the rules that individuals follow. we model aggregation of the pea aphid, acyrthosiphon pisum. specifically, we conduct experiments to track the motion of aphids walking in a featureless circular arena in order to d ...201324376691
comparative analyses of salivary proteins from three aphid species.saliva is a critical biochemical interface between aphids and their host plants; however, the biochemical nature and physiological functions of aphid saliva proteins are not fully elucidated. in this study we used a multidisciplinary proteomics approach combining liquid chromatography-electrospray ionization tandem mass spectrometry and two-dimensional differential in-gel electrophoresis/matrix-assisted laser desorption/ionization time-of-flight/mass spectrometry to compare the salivary proteins ...201424382153
inheritance patterns of secondary symbionts during sexual reproduction of pea aphid biotypes.herbivorous insects frequently harbor bacterial symbionts that affect their ecology and evolution. aphids host the obligatory endosymbiont buchnera, which is required for reproduction, together with facultative symbionts whose frequencies vary across aphid populations. these maternally transmitted secondary symbionts have been particularly studied in the pea aphid, acyrthosiphon pisum, which harbors at least 8 distinct bacterial species (not counting buchnera) having environmentally dependent ef ...201424382700
dsrna degradation in the pea aphid (acyrthosiphon pisum) associated with lack of response in rnai feeding and injection assay.over the past decade, rna interference (rnai), the sequence-specific suppression of gene expression, has proven very promising for molecular research in many species, including model insects as tribolium castaneum and apis mellifera. it showed its usefulness to analyze gene function and its potential to manage pest populations and reduce disease pathogens. however, in several insects, the efficiency of rnai is low or very variable at best. one of the factors that could influence rnai efficiency ...201424394433
pathways of auxin transport in the intact pea seedling (pisum sativum l.).when small colonies of the pea aphid [acyrthosiphon pisum (harris)] were established on the stem of meteor dwarf pea seedlings (pisum sativum l.), (14)c was found in the honeydew 4.5 h after applying iaa-1-(14)c to a fully-expanded foliage leaf. in contrast, no activity was found in the honeydew or aphids 4.5 h after the application of iaa-1-(14)c to the intact apical bud even though the internode upon which the aphids were feeding contained high levels of (14)c. the lack of radio-activity in ap ...197224477401
aphid polyphenisms: trans-generational developmental regulation through viviparity.polyphenism, in which multiple discrete phenotypes develop from a single genotype, is considered to have contributed to the evolutionary success of aphids. of the various polyphenisms observed in the complex life cycle of aphids, the reproductive and wing polyphenisms seen in most aphid species are conspicuous. in reproductive polyphenism, the reproductive modes can change between viviparous parthenogenesis and sexual reproduction in response to the photoperiod. under short-day conditions in aut ...201424478714
effects of a protease inhibitor protein from xenorhabdus bovienii on physiology of pea aphid (acyrthosiphon pisum).the effects of a protease inhibitor protein from xenorhabdus bovienii strain xbi1 (xbpi-1) on biochemistry and physiology of pea aphid (acyrthosiphon pisum) were studied, and the effects of xbpi-1 on the activities of aphid aminopeptidase and the concentrations of carbohydrates, free amino acids and lipids in a. pisum were determined. the results showed that the activity of aminopeptidase was reduced 18.30% by xbpi-1 in vitro assays. in addition, the total sugar, glycogen, and lipid concentratio ...201424485320
a recombinant fusion protein containing a spider toxin specific for the insect voltage-gated sodium ion channel shows oral toxicity towards insects of different orders.recombinant fusion protein technology allows specific insecticidal protein and peptide toxins to display activity in orally-delivered biopesticides. the spider venom peptide δ-amaurobitoxin-pi1a, which targets insect voltage-gated sodium channels, was fused to the "carrier" snowdrop lectin (gna) to confer oral toxicity. the toxin itself (pi1a) and an amaurobitoxin/gna fusion protein (pi1a/gna) were produced using the yeast pichia pastoris as expression host. although both proteins caused mortali ...201424486516
derivation and validation of a binomial sequential decision plan for managing pea aphids (hemiptera: aphididae) as direct pests of dry pea (fabales: fabaceae) in the pacific northwest.we developed a binomial sequential decision plan that classifies the economic status of nonviruliferous pea aphids, acyrthosiphon pisum (harris) (hemiptera: aphididae), in commercial dry peas, pisum sativum l. (fabales: fabaceae), in the palouse region of northern idaho and eastern washington state. relationships between mean pea aphid density per plant (x) and the proportion of aphid-infested plants (pi) were determined by in situ visual counts of 100 plants on each of 27 seasonal dates during ...201324498764
rna interference of nadph-cytochrome p450 reductase of the rice brown planthopper, nilaparvata lugens, increases susceptibility to insecticides.nadph-cytochrome p450 reductase (cpr) is essential for numerous biological reactions catalysed by microsomal cytochrome p450 monooxygenases (p450s). knockdown of cpr in several insects leads to developmental defects and increased susceptibility to insecticides. however, information about the role of cpr in the brown planthopper, nilaparvata lugens, is still unavailable.201524515640
[translocation of labeled indolyl-3-acetic acid in sieve tubes of vicia faba].young plants of vicia faba fed through the first primary leaf with a 5\10(-3) mol solution of indolylacetic acid (iaa) show a bending of the stem above the treated leaf after a certain amount of time. the movement of the growth substance is several times faster than it is in the parenchyma. some hours later, the stem growths upright again.when labeled iaa [indolyl-3-(acetic acid-2-(14)c)] is used, the autoradiographs of the plants show labeled material in the stem, in roots, and in the youngest ...196724522706
dynamic recruitment of amino acid transporters to the insect/symbiont interface.symbiosis is well known to influence bacterial symbiont genome evolution and has recently been shown to shape eukaryotic host genomes. intriguing patterns of host genome evolution, including remarkable numbers of gene duplications, have been observed in the pea aphid, a sap-feeding insect that relies on a bacterial endosymbiont for amino acid provisioning. previously, we proposed that gene duplication has been important for the evolution of symbiosis based on aphid-specific gene duplication in a ...201424528556
ems mutagenesis in the pea aphid acyrthosiphon pisum.in aphids, clonal individuals can show distinct morphologic traits in response to environmental cues. such phenotypic plasticity cannot be studied with classical genetic model organisms such as caenorhabditis elegans or drosophila melanogaster. the genetic basis of this biological process remain unknown, as mutations affecting this process are not available in aphids. here, we describe a protocol to treat third-stage larvae with an alkylating mutagen, ethyl methanesulfonate (ems), to generate ra ...201424531730
aphid facultative symbionts reduce survival of the predatory lady beetle hippodamia convergens.non-essential facultative endosymbionts can provide their hosts with protection from parasites, pathogens, and predators. for example, two facultative bacterial symbionts of the pea aphid (acyrthosiphon pisum), serratia symbiotica and hamiltonella defensa, protect their hosts from parasitism by two species of parasitoid wasp. previous studies have not explored whether facultative symbionts also play a defensive role against predation in this system. we tested whether feeding on aphids harboring ...201424555501
[translocation of(14)c-labeled assimilates in light and darkness invicia faba].by methods involving autoradiography, historadiography of water soluble activity, girdling, and honey dew-chronograms, the uptake, assimilation and translocation of(14)c-labeled tracers have been studied.vicia faba, grown in aerated nutrient solution, was treated with nah(14)co3, sucrose-(14)c-(u), and urea-(14)c. translocation experiments have been carried out in a cooling room at 14°c. only phloem-mobile activity is translocated when the leaf is fed with h(14)co 3 (-) in the light; in the dark ...196624557941
are naringenin and quercetin useful chemicals in pest-management strategies?the effects of two polyphenolic flavonoids (flavanone naringenin and flavonol quercetin) on development, fecundity, and mortality of the pea aphid, acyrthosiphon pisum harris (hemiptera: aphididae), were determined in vitro, on an artificial diets. also determined in vitro (dc epg method), on sucrose-agarose gels, were the effects of flavonoids on the probing and feeding behavior of adult apterae. when added to a liquid diet, higher concentrations of studied flavonoids increased the developmenta ...201424563648
how rapid is aphid-induced signal transfer between plants via common mycelial networks?arbuscular mycorrhizal (am) fungi are important plant mutualists that can connect roots of neighboring plants to form common mycelial networks. a recent study demonstrated that these networks can act as conduits for aphid-induced signals between plants, activating chemical defenses in uninfested neighboring plants so that they become unattractive to aphids but attractive to their enemies (parasitoids). the benefit to the neighboring plants will increase if the signal speed is rapid, enabling the ...201324563703
interactions between extrafloral nectaries, aphids and ants: are there competition effects between plant and homopteran sugar sources?broad bean (vicia faba), an annual plant bearing extrafloral nectaries (efn) at the base of the upper leaves, is regularly infested by two aphid species, aphis fabae and acyrthosiphon pisum. efn and a. fabae are commonly attended by the ant, lasius niger, while ac. pisum usually remains uninfested. sugar concentration and sugar composition of extrafloral nectar did not change significantly after aphid infestation. the sugar concentration was significantly higher in efn (c. 271 µg µl(-1)) than in ...200124577698
the leucine-rich repeat receptor-like kinase brassinosteroid insensitive1-associated kinase1 and the cytochrome p450 phytoalexin deficient3 contribute to innate immunity to aphids in arabidopsis.the importance of pathogen-associated molecular pattern-triggered immunity (pti) against microbial pathogens has been recently demonstrated. however, it is currently unclear if this layer of immunity mediated by surface-localized pattern recognition receptors (prrs) also plays a role in basal resistance to insects, such as aphids. here, we show that pti is an important component of plant innate immunity to insects. extract of the green peach aphid (gpa; myzus persicae) triggers responses charact ...201424586042
expression pattern analysis of odorant-binding proteins in the pea aphid acyrthosiphon pisum.odorant-binding proteins (obps) are soluble proteins mediating chemoreception in insects. in previous research, we investigated the molecular mechanisms adopted by aphids to detect the alarm pheromone (e)-β-farnesene and we found that the recognition of this and structurally related molecules is mediated by obp3 and obp7. here, we show the differential expression patterns of 5 selected obps (obp1, obp3, obp6, obp7, obp8) obtained performing quantitative rt-pcr and immunolocalization experiments ...201524591440
the cytogenetic architecture of the aphid genome.in recent years aphids, with their well-defined polyphenism, have become favoured as model organisms for the study of epigenetic processes. the availability of the pea aphid (acyrthosiphon pisum) genome sequence has engendered much research aimed at elucidating the mechanisms by which the phenotypic plasticity of aphids is inherited and controlled. yet so far this research effort has paid little attention to the cytogenetic processes that play a vital part in the organisation, expression and inh ...201524593177
exposure to natural pathogens reveals costly aphid response to fungi but not bacteria.immune responses are costly, causing trade-offs between defense and other host life history traits. aphids present a special system to explore the costs associated with immune activation since they are missing several humoral and cellular mechanisms thought important for microbial resistance, and it is unknown whether they have alternative, novel immune responses to deal with microbial threat. here we expose pea aphids to an array of heat-killed natural pathogens, which should stimulate immune r ...201424634732
delayed virulence and limited costs promote fecundity compensation upon infection.individuals invest limited resources across vital tasks such as reproduction and survival. individuals can spread reproductive investment over their lifetime, but cues of death or reduced fitness can influence this investment. in some systems, cues of infection induce early but costly reproduction through fecundity compensation as future reproduction becomes uncertain. a key aspect of parasite biology is the delay between exposure to parasites and the onset of virulence. this creates an importan ...201424642493
differential induction of pisum sativum defense signaling molecules in response to pea aphid infestation.this study demonstrates the sequence of enhanced generation of signal molecules such as phytohormones, i.e. jasmonic acid (ja), ethylene (et), salicylic acid (sa), and a relatively stable free radical, nitric oxide (no), in response of pisum sativum l. cv. cysterski seedling leaves to the infestation of pea aphid acyrthosiphon pisum (harris) at a varied population size. in time from 0 to 96h after a. pisum infestation these signal molecules accumulated transiently. moreover, the convergence of t ...201424656330
orysata, a jacalin-related lectin from rice, could protect plants against biting-chewing and piercing-sucking insects.the present study reports the insecticidal activity of orysata, a lectin from rice with mannose specificity, belonging to the family of jacalin-related lectins. the effect of orysata was investigated against three important pest insects in agriculture: the beet armyworm spodoptera exigua hübner (lepidoptera: noctuidae), and two aphid pests: green peach aphid myzus persicae sulzer and pea aphid acyrthosiphon pisum (hemiptera: aphidoidea). bioassays with s. exigua and m. persicae were performed us ...201424656332
species interactions and a chain of indirect effects driven by reduced precipitation.climate change can affect species directly and indirectly by altering interactions between species within communities. these indirect effects can ramify through a community and affect many species, including some that may not have been directly affected by the perturbation. identifying these chains of indirect effects is difficult, and most studies only follow indirect effects across two or three species. here, we use a factorial field experiment to demonstrate that precipitation affects spotted ...201424669741
an ecological cost associated with protective symbionts of aphids.beneficial symbioses are widespread and diverse in the functions they provide to the host ranging from nutrition to protection. however, these partnerships with symbionts can be costly for the host. such costs, so called "direct costs", arise from a trade-off between allocating resources to symbiosis and other functions such as reproduction or growth. ecological costs may also exist when symbiosis negatively affects the interactions between the host and other organisms in the environment. althou ...201424683464
solenopsis invicta virus 3: mapping of structural proteins, ribosomal frameshifting, and similarities to acyrthosiphon pisum virus and kelp fly virus.solenopsis invicta virus 3 (sinv-3) is a positive-sense single-stranded rna virus that infects the red imported fire ant, solenopsis invicta. we show that the second open reading frame (orf) of the dicistronic genome is expressed via a frameshifting mechanism and that the sequences encoding the structural proteins map to both orf2 and the 3' end of orf1, downstream of the sequence that encodes the rna-dependent rna polymerase. the genome organization and structural protein expression strategy re ...201424686475
genetic variation in resistance and fecundity tolerance in a natural host-pathogen interaction.individuals vary in their ability to defend against pathogens. determining how natural selection maintains this variation is often difficult, in part because there are multiple ways that organisms defend themselves against pathogens. one important distinction is between mechanisms of resistance that fight off infection, and mechanisms of tolerance that limit the impact of infection on host fitness without influencing pathogen growth. theory predicts variation among genotypes in resistance, but n ...201424689981
elevated co2 alters the feeding behaviour of the pea aphid by modifying the physical and chemical resistance of medicago truncatula.elevated co(2) compromises the resistance of leguminous plants against chewing insects, but little is known about whether elevated co(2) modifies the resistance against phloem-sucking insects or whether it has contrasting effects on the resistance of legumes that differ in biological nitrogen fixation. we tested the hypothesis that the physical and chemical resistance against aphids would be increased in jemalong (a wild type of medicago truncatula) but would be decreased in dnf1 (a mutant witho ...201424697655
natural occurrence of entomophthoroid fungi of aphid pests on medicago sativa l. in argentina.four species of entomophthoroid fungi, pandora neoaphidis (entomophthorales: entomophthoraceae), zoophthora radicans (entomophthorales: entomophthoraceae), entomophthora planchoniana (entomophthorales: entomophthoraceae) and neozygites fresenii (neozygitales: neozygitaceae) were found to infect aphis craccivora, therioaphis trifolii, and acyrthosiphon pisum and unidentified species of acyrthosiphon on lucerne in argentina. samples were collected from five sites (ceres, rafaela, sarmiento, monte ...201424721275
characterization of an aphid-specific, cysteine-rich protein enriched in salivary glands.aphids secrete saliva into the phloem during their infestation of plants. previous studies have identified numerous saliva proteins, but little is known about the characteristics (physical and chemical) and functions of these proteins in aphid-plant interactions. this study characterized an unknown protein (acypi39568) that was predicted to be enriched in the salivary glands of pea aphid. this protein belongs to an aphid-specific, cysteine-rich protein family that contains 14 conserved cysteines ...201424731868
accelerated evolution of morph-biased genes in pea aphids.phenotypic plasticity, the production of alternative phenotypes (or morphs) from the same genotype due to environmental factors, results in some genes being expressed in a morph-biased manner. theoretically, these morph-biased genes experience relaxed selection, the consequence of which is the buildup of slightly deleterious mutations at these genes. over time, this is expected to result in increased protein divergence at these genes between species and a signature of relaxed purifying selection ...201424770714
comparison of the wing polyphenic response of pea aphids (acyrthosiphon pisum) to crowding and predator cues.1. pea aphids (acyrthosiphon pisum harris; hemiptera: aphididae) exhibit transgenerational wing polyphenism, in which unwinged females produce genetically identical winged offspring in response to environmental cues such as overcrowding and predation risk that indicate poor habitat quality. 2. laboratory experiments were carried out to explore the intensity of the wing polyphenic response of pea aphids exposed to cues from ladybird predators and crowding, and their response was compared to pea a ...201424791058
neonicotinoid binding, toxicity and expression of nicotinic acetylcholine receptor subunits in the aphid acyrthosiphon pisum.neonicotinoid insecticides act on nicotinic acetylcholine receptor and are particularly effective against sucking pests. they are widely used in crops protection to fight against aphids, which cause severe damage. in the present study we evaluated the susceptibility of the pea aphid acyrthosiphon pisum to the commonly used neonicotinoid insecticides imidacloprid (imi), thiamethoxam (tmx) and clothianidin (clt). binding studies on aphid membrane preparations revealed the existence of high and low ...201424801634
reliable protocols for whole-mount fluorescent in situ hybridization (fish) in the pea aphid acyrthosiphon pisum: a comprehensive survey and analysis.rna in situ hybridization (ish), including chromogenic ish (cish) and fluorescent ish (fish), has become a powerful tool for revealing the spatial distribution of gene transcripts in model organisms. previously, we developed a robust protocol for whole-mount rna cish in the pea aphid acyrthosiphon pisum, an emerging insect genomic model. in order to improve the resolving capacity of gene detection, we comprehensively surveyed current protocols of whole-mount rna-fish and developed protocols that ...201424850784
posterior localization of apvas1 positions the preformed germ plasm in the sexual oviparous pea aphid acyrthosiphon pisum.germline specification in some animals is driven by the maternally inherited germ plasm during early embryogenesis (inheritance mode), whereas in others it is induced by signals from neighboring cells in mid or late development (induction mode). in the metazoa, the induction mode appears as a more prevalent and ancestral condition; the inheritance mode is therefore derived. however, regarding germline specification in organisms with asexual and sexual reproduction it has not been clear whether b ...201424855557
new insight into the rna interference response against cathepsin-l gene in the pea aphid, acyrthosiphon pisum: molting or gut phenotypes specifically induced by injection or feeding treatments.rna interference (rnai) has been widely and successfully used for gene inactivation in insects, including aphids, where dsrna administration can be performed either by feeding or microinjection. however, several aspects related to the aphid response to rnai, as well as the influence of the administration method on tissue response, or the mixed success to observe phenotypes specific to the gene targeted, are still unclear in this insect group. in the present study, we made the first direct compar ...201424859468
evidence of horizontal transfer of non-autonomous lep1 helitrons facilitated by host-parasite interactions.horizontal transfer (ht) of transposable elements has been recognized to be a major force driving genomic variation and biological innovation of eukaryotic organisms. however, the mechanisms of ht in eukaryotes remain poorly appreciated. the non-autonomous helitron family, lep1, has been found to be widespread in lepidopteran species, and showed little interspecific sequence similarity of acquired sequences at 3' end, which makes lep1 a good candidate for the study of ht. in this study, we descr ...201424874102
identification of the main venom protein components of aphidius ervi, a parasitoid wasp of the aphid model acyrthosiphon pisum.endoparasitoid wasps are important natural enemies of the widely distributed aphid pests and are mainly used as biological control agents. however, despite the increased interest on aphid interaction networks, only sparse information is available on the factors used by parasitoids to modulate the aphid physiology. our aim was here to identify the major protein components of the venom injected at oviposition by aphidius ervi to ensure successful development in its aphid host, acyrthosiphon pisum.201424884493
synthesis and biological activity of fluorescent neonicotinoid insecticide thiamethoxam.here, we describe the synthesis of two new fluorescent derivatives of thiamethoxam and compared their toxicity on aphid acyrthosiphon pisum and their mode of action on insect nicotinic acetylcholine receptors expressed on the sixth abdominal ganglion. the compound 3 with two 2-chlorothiazole moieties was found to be more toxic using toxicological bioassays 24 h and 48 h after exposure while compound 4 appeared more active using cockroach ganglionic depolarization. interestingly, thiamethoxam app ...201424915877
aphid-encoded variability in susceptibility to a parasitoid.many animals exhibit variation in resistance to specific natural enemies. such variation may be encoded in their genomes or derived from infection with protective symbionts. the pea aphid, acyrthosiphon pisum, for example, exhibits tremendous variation in susceptibility to a common natural enemy, the parasitic wasp aphidius ervi. pea aphids are often infected with the heritable bacterial symbiont, hamiltonella defensa, which confers partial to complete resistance against this parasitoid dependin ...201424916045
life-history trade-offs mediate 'personality' variation in two colour morphs of the pea aphid, acyrthosiphon pisum.life-history trade-offs are considered a major driving force in the emergence of consistent behavioural differences (personality variation); but empirical tests are scarce. we investigated links between a personality trait (escape response), life-history and state variables (growth rate, size and age at first reproduction, age-dependent reproductive rates, lifetime reproductive success, life span) in red and green colour morphs of clonal pea aphids, acyrthosiphon pisum. escape response (dropping ...201524942327
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