| purification of pea enation mosaic virus from its pea aphid vector, acyrthosiphon pisum, and aphid-transmission characteristics. | | 1973 | 4119354 |
| correlation of transmission of bean yellow mosaic virus with salivation activity of acyrthosiphon pisum (homoptera: aphididae). | | 1969 | 5374177 |
| [diapause of eggs from the pea aphid (acyrthosiphon onobrychis boyer, homoptera, aphididae)]. | | 1970 | 5529642 |
| differential transmission of two pea enation mosaic virus isolates by the pea aphid, acyrthosiphon pisum (harris). | | 1967 | 6062176 |
| occurrence and transmission of facultative endosymbionts in aphids. | the occurrence of a secondary bacterial symbiont (pass) of pea aphid, acyrthosiphon pisum (harris), was detected by polymerase chain reaction (pcr) with specific nucleotide primers based on pass 16s rdna nucleotide sequences from over 80% (50/57) of clones of pea aphid collected from widely separated locations in california. pass was also detected by pcr in both red and green phenotypes of rose aphid,macrosiphum rosae (l.), but not in six other species of aphids examined, including blue alfalfa ... | 1997 | 9058541 |
| structure of the dnaa region of the endosymbiont, buchnera aphidicola, of aphid schizaphis graminum. | buchnera aphidicola is an intracellular prokaryote (endosymbiont) that lives in the body cavity of the aphid. phylogenetic studies indicated that it is closely related to escherichia coli and members of enterobacteria. the gene order of the region containing the dnaa gene is well conserved in many bacteria. seven genes of the endosymbiont of the aphid schizaphis graminum, gyrb, dnan, dnaa, rpmh, rnpa, yidd, and 60k. were found to be homologous in sequence and relative location to those of e. col ... | 1996 | 9097044 |
| physical and genetic map of the genome of buchnera, the primary endosymbiont of the pea aphid acyrthosiphon pisum. | the genome of buchnera, an endosymbiotic bacterium of the pea aphid acyrthosiphon pisum, was characterized by pulse-field gel electrophoresis (pfge) as a circular dna molecule of 657 kb. the enzymes i-ceui, cpoi, apai, smai, naei, sacii, mlui, fspi, and nrui were used to cleave the dna of buchnera into fragments of suitable size for pfge analysis. a physical map of the buchnera genome, including restriction fragments from seven of these enzymes, was constructed using double cutting, partial dige ... | 1999 | 9929382 |
| in vitro interactions of the aphid endosymbiotic syml chaperonin with barley yellow dwarf virus. | barley yellow dwarf virus (bydv)-vector relationships suggest that there are specific interactions between bydv virions and the aphid's cellular components. however, little is known about vector factors that mediate virion recognition, cellular trafficking, and accumulation within the aphid. symbionins are molecular chaperonins produced by intracellular endosymbiotic bacteria and are the most abundant proteins found in aphids. to elucidate the potential role of symbionins in bydv transmission, w ... | 1997 | 8985385 |
| a new rickettsia from a herbivorous insect, the pea aphid acyrthosiphon pisum (harris). | an undescribed, maternally heritable, rod-shaped bacterium (or "tertiary symbiont") was detected by microscopy in hemolymph of about half (59/122) of pea aphid [acyrthosiphon pisum (harris)] clones collected from widely separated locations in california. on the basis of molecular phylogenetic analysis of 16s rdna sequences, the bacterium was clearly placed among other rickettsia in the alpha-subgroup of proteobacteria, close to rickettsia bellii-a rickettsia found in ticks. a pcr assay was devel ... | 1996 | 8662184 |
| the tryptophan biosynthetic pathway of aphid endosymbionts (buchnera): genetics and evolution of plasmid-associated anthranilate synthase (trpeg) within the aphididae. | the bacterial endosymbionts (buchnera) from the aphids rhopalosiphum padi, r. maidis, schizaphis graminum, and acyrthosiphon pisum contain the genes for anthranilate synthase (trpeg) on plasmids made up of one or more 3.6-kb units. anthranilate synthase is the first as well as the rate-limiting enzyme in the tryptophan biosynthetic pathway. the amplification of trpeg on plasmids may result in an increase of enzyme protein and overproduction of this essential amino acid, which is required by the ... | 1996 | 8642610 |
| the 'tubulin-like' s1 protein of spirochaeta is a member of the hsp65 stress protein family. | a 65-kda protein (called s1) from spirochaeta bajacaliforniensis was identified as 'tubulin-like' because it cross-reacted with at least four different antisera raised against tubulin and was isolated, with a co-polymerizing 45-kda protein, by warm-cold cycling procedures used to purify tubulin from mammalian brain. furthermore, at least three genera of non-cultivable symbiotic spirochetes (pillotina, diplocalyx, and hollandina) that contain conspicuous 24-nm cytoplasmic tubules displayed a stro ... | 1993 | 8155849 |
| gut microbe of aphid closely related to its intracellular symbiont. | pea aphid, acyrthosiphon pisum harbors prokaryotic intracellular symbionts and, at least, two species of gut microbes. it has been shown that the aphid symbiont is more closely related to escherichia coli than to any other free-living bacterium. analysis of rflp of their 16s rdna and groe homologues suggested that one of the gut microbes is a close relative of e. coli and that the aphid symbiont is still closer to this microbe than to e. coli. in addition, the optimal temperature for the growth ... | 1993 | 7908835 |
| molecular analysis of ribosomal dna from the aphid amphorophora idaei and an associated fungal organism. | the ribosomal dna cistron from the large raspberry aphid, amphorophora idaei (hemiptera: aphididae), has been mapped by restriction analysis. the results showed that the map of a. idaei was similar to those of the previously characterized aphids schizaphis graminum and acyrthosiphon pisum. an extra bgl ii site was found in some of the ribosomal dna intergenic spacer repeats in a. idaei. using in-situ hybridization to aphid mitotic chromosomes it was demonstrated that probes derived from this reg ... | 1994 | 7894750 |
| molecular characterization of the leucine plasmid from buchnera aphidicola, primary endosymbiont of the aphid acyrthosiphon pisum. | the complete sequence of the leucine plasmid of buchnera aphidicola from the aphid acyrthosiphon pisum (pleu-bap) is reported. its gene organization was concordant with those of other leucine plasmids of buchnera from aphids of the aphidini and macrosiphini tribes. three inverted repeats are present in pleu-bap. two of them are also present in pleu from the family aphididae: (i) sir1, located downstream the leucine operon, resembles a rho-independent terminator of transcription, and (ii) lir1, l ... | 2000 | 10688696 |
| prephenate dehydratase from the aphid endosymbiont (buchnera) displays changes in the regulatory domain that suggest its desensitization to inhibition by phenylalanine. | buchnera aphidicola, the prokaryotic endosymbiont of aphids, complements dietary deficiencies with the synthesis and provision of several essential amino acids. we have cloned and sequenced a region of the genome of b. aphidicola isolated from acyrthosiphon pisum which includes the two-domain aroq/phea gene. this gene encodes the bifunctional chorismate mutase-prephenate dehydratase protein, which plays a central role in l-phenylalanine biosynthesis. two changes involved in the overproduction of ... | 2000 | 10781569 |
| an association between phlebotomine sandflies and aphids in the peruvian andes. | as the composition of natural sugars in the diet of adult sandflies (diptera: psychodidae: phlebotominae) may affect the development of leishmania (kinetoplastida: trypanosomatidae) in sandfly guts, and so play an important role in the epidemiology of leishmaniasis, there is increasing interest in the sources of sugars for wild sandflies. advanced chromatography techniques have provided indirect evidence that wild sandflies feed on honeydew, a substance released by aphids (hemiptera: aphididae) ... | 1995 | 7787219 |
| phylogenetic affiliation of bev, a bacterial parasite of the leafhopper euscelidius variegatus, on the basis of 16s rdna sequences. | the phylogenetic relationship of a nonflagellated, gram-negative, rod-shaped intracellular bacterial parasite (bev) of the leafhopper euscelidius variegatus to other bacteria within the class proteobacteria was determined by sequence analysis of 16s rdnas. the presence of specific signature nucleotides showed this bacterium to be a member of the gamma-3 subdivision of the proteobacteria. phylogenetic analysis based on maximum parsimony placed bev within a clade in the enterobacteriaceae, which i ... | 1993 | 7763405 |
| the secondary endosymbiotic bacterium of the pea aphid acyrthosiphon pisum (insecta: homoptera). | the secondary intracellular symbiotic bacterium (s-symbiont) of the pea aphid acyrthosiphon pisum was investigated to determine its prevalence among strains, its phylogenetic position, its localization in the host insect, its ultrastructure, and the cytology of the endosymbiotic system. a total of 14 aphid strains were examined, and the s-symbiont was detected in 4 japanese strains by diagnostic pcr. two types of eubacterial 16s ribosomal dna sequences were identified in disymbiotic strains; one ... | 2000 | 10877764 |
| behavioural thermoregulation in acyrthosiphon pisum (homoptera: aphididae): the effect of parasitism by aphidius ervi (hymenoptera: braconidae). | the effects of parasitisation by aphidius ervi on the thermoregulatory behaviour of the pea aphid acyrtosiphon pisum were studied in alfalfa fields and in an experimental thermal gradient. in the field, mummies were found exclusively on the adaxial surface of the upper leaves, and aphids in the mid canopy. the adaxial surface of the upper leaves was ca. 2 degrees c hotter that the mid-canopy. in the thermal gradient, the thermal effect (selected minus exposure temperature) was higher in magnitud ... | 2001 | 11163929 |
| cloning and characterization of the ribosomal protein genes in the spc operon of a prokaryotic endosymbiont of the pea aphid, acyrthosiphon kondoi. | to correlate a prokaryotic endosymbiont in the pea aphid, acyrthosiphon kondoi, with the endosymbionts in related aphid species as well as with free-living bacteria and subcellular organelles, and to study the mode of its gene expression within aphid cells, we have cloned and characterized the genes encoding ribosomal proteins s3, l16, l29, s17, l14, l24, l5, s14, s8, l6, l18, s5, l30, l15 and secretion protein y (sec y) from the s10 and spc ribosomal protein gene operons of this endosymbiont. t ... | 1994 | 7584036 |
| intraspecies variability in transmission efficiency of stylet-borne viruses by the pea aphid (acyrthosiphon pisum). | the efficiency of bean yellow mosaic virus (bymv; potyvirus group) tranasmission from pea to pea plants by 36 clones of the pea aphid (acyrthosiphon pisum) was studied. the efficiency of the clones varied; it was not related to the aphid colour form (green, red or yellow) or the origin of the clone (host plant, geographic area). with alfalfa mosaic virus, the virus-vector relationships concerning transmission efficiency were, in general, similar to those found with bymv. the behaviour of the clo ... | 1980 | 6108064 |
| retention of inoculativity in the transmission of pea enation mosaic virus by pea aphids as associated with virus isolates, aphid reproduction and excretion. | | 1967 | 6028944 |
| "recharging" pea aphids with pea enation mosaic virus. | | 1966 | 5928791 |
| the fate of pea enation mosaic virus in its pea aphid vector, acyrthosiphon pisum (harris). | | 1972 | 4565616 |
| mutualism based on stress: selective synthesis and phosphorylation of a stress protein by an intracellular symbiont. | the effects of a temperature shift-up and various metabolic inhibitors on the protein synthesis of an endosymbiont isolated from the pea aphid were studied. the syntheses of at least three major polypeptides were stimulated transiently immediately after a temperature shift-up, and treatment with ethanol and heavy metals (cd2+ and as2+). one of these proteins, the 63 kda heat-shock protein (63-kda hsp), was immunoprecipitated with antiserum raised against symbionin, which is selectively synthesiz ... | 1992 | 1618730 |
| fate of pea enation mosaic virus in pemv-injected pea aphids. | | 1975 | 1146226 |
| ultrastructure of pea aphid mycetocytes: evidence for symbiote secretion. | a detailed investigation into the ultrastructure of the pea aphid mycetocytes and their contained symbiotes and organelles was carried out with the transmission electron microscope. the most striking observation was the presence of small vesicles in the space between the primary symbiote cell wall and membrane envelope (outer membrane space). the vesicles appear to form by a budding process at the outer cell wall layer. subsequently, the vesicles, we suggest, may move out into the mycetocyte cyt ... | 1975 | 807329 |
| a new approach to measure the lp50 of pea enation mosaic virus in its vector acyrthosiphon pisum. | | 1978 | 726252 |
| structural differences between pea enation mosaic virus strains affecting transmissibility by acyrthosiphon pisum (harris). | | 1979 | 419684 |
| effects of fungal infection on the alarm response of pea aphids | pea aphids (acyrthosiphon pisum, homoptera: aphididae) infected with the fungal pathogen erynia neoaphidis (zygomycetes: entomophthorales) were less sensitive to the aphid alarm pheromone (e)-beta-farnesene than uninfected aphids. approximately 83% of the healthy aphids and 45% of the infected aphids (2 and 3 days post-inoculation) responded to the alarm pheromone. the percentage of nonresponding aphids increased as the disease progressed. when squeezed (simulated attack) healthy aphids and aphi ... | 1999 | 10388549 |
| low genetic diversity among pea aphid (acyrthosiphon pisum) biotypes of different plant affiliation. | genetic diversity in the pea aphid acyrthosiphon pisum was investigated by a restriction fragment length polymorphism (rflp) analysis of three maternally inherited genomes (mitochondrial dna and plasmids of the symbiotic bacteria buchnera). twenty-nine parthenogenetic clones of three a. pisum biotypes, defined by their capacity to use the legume crops pea, alfalfa and red clover, respectively, were analysed, and a total of 67 restriction sites was scored. no restriction site variation in the mit ... | 1999 | 10383681 |
| facultative bacterial symbionts in aphids confer resistance to parasitic wasps. | symbiotic relationships between animals and microorganisms are common in nature, yet the factors controlling the abundance and distributions of symbionts are mostly unknown. aphids have an obligate association with the bacterium buchnera aphidicola (the primary symbiont) that has been shown to contribute directly to aphid fitness. in addition, aphids sometimes harbor other vertically transmitted bacteria (secondary symbionts), for which few benefits of infection have been previously documented. ... | 2003 | 12563031 |
| selection by phage display of a variant mustard trypsin inhibitor toxic against aphids. | the mustard trypsin inhibitor, mti-2, is a potent inhibitor of trypsin with no activity towards chymotrypsin. mti-2 is toxic for lepidopteran insects, but has low activity against aphids. in an attempt to improve the activity of the inhibitor towards aphids, a library of inhibitor variants was constructed and cloned into the prlac3 phagemid vector. the library of 9.3 x 107 independent colonies was created by randomisation of a stretch of five consecutive codons in the reactive site. repeated sel ... | 2003 | 12581313 |
| the role of rdna genes in x chromosome association in the aphid acyrthosiphon pisum. | silver staining of mitotic metaphases of the aphid a. pisum reveals the presence of argentophilic bridges connecting the two x chromosomes. the presence of nucleolar material connecting sex chromosomes seems to be quite a common phenomenon in organisms belonging to very different phyla, and suggests a role of nucleolar proteins in chromosome association and disjunction. in somatic cells of a. pisum, bridges connecting x chromosomes are detectable not only after silver staining but also after cma ... | 1999 | 10382287 |
| method to immobilize the aphid-pathogenic fungus erynia neoaphidis in an alginate matrix for biocontrol | erynia neoaphidis is an important fungal pathogen of aphid pests worldwide. there have been few reported attempts to formulate this natural agent for use in biocontrol. in the current study, factors involved in the immobilization of e. neoaphidis hyphae in an alginate matrix were investigated. hyphae of two isolates cultured in liquid medium were 220 to 620 &mgr;m in length and 7 to 19 &mgr;m in diameter with a 74 to 83% cytoplasmic content. the optimal concentration of low-viscosity sodium algi ... | 1998 | 9797274 |
| differential display of mrnas related to amino acid metabolism in the endosymbiotic system of aphids. | bacteriocytes harbouring buchnera endosymbionts were isolated from young and old aphids, acyrthosiphon pisum, and their mrna populations were examined by the differential cdna display and quantitative reverse transcriptase-polymerase chain reaction (rt-pcr) technique. it was suggested that several gene products are produced when the symbiotic system is well organized in the young insect, whereas others are produced after the system becomes degenerate in old aphids. among the gene products that w ... | 1997 | 9569646 |
| implications of predator foraging on aphid pathogen dynamics. | the foraging behavior of starved and nonstarved second and fourth instar coccinella septempunctata larvae on dead acyrthosiphon pisum aphids, either infected with the entomopathogenic fungus erynia neoaphidis (sporulating) or uninfected, was examined. larvae searched for longer and fed less when presented with infected rather than uninfected a. pisum. although no sporulating infected aphids were completely consumed, both adult and larval ladybirds can still be considered as intraguild predators. ... | 1998 | 9538028 |
| structure and expression of the dnakj operon of buchnera, an intracellular symbiotic bacteria of aphid. | buchnera sp., an intracellular symbiont of the pea aphid (acyrthosiphon pisum harris), is a close phylogenetical relative of escherichia coli, and synthesizes a large amount of symbionin, a groel homolog. the other heat shock protein homologs, which are not expressed as much as symbionin, have not been studied yet. in this study, we cloned the dnak and dnaj genes of buchnera, and revealed that its dnak and dnaj are structurally very similar to those of e. coli. amino acid residues and motifs pro ... | 1997 | 9276669 |
| isolation and characterization of apse-1, a bacteriophage infecting the secondary endosymbiont of acyrthosiphon pisum. | a bacteriophage infecting the secondary endosymbiont of the pea aphid acyrthosiphon pisum was isolated and characterized. the phage was tentatively named bacteriophage apse-1, for bacteriophage 1 of the a. pisum secondary endosymbiont. the apse-1 phage particles morphologically resembled those of species of the podoviridae. the complete nucleotide sequence of the bacteriophage apse-1 genome was elucidated, and its genomic organization was deduced. the genome consists of a circularly permuted and ... | 1999 | 10489345 |
| faba bean necrotic yellows virus (genus nanovirus) requires a helper factor for its aphid transmission. | purified faba bean necrotic yellows virus (fbnyv; genus nanovirus) alone is not transmissible by its aphid vector, acyrthosiphon pisum, regardless of whether it is acquired from artificial diets or directly microinjected into the aphid's hemocoel. the purified virus contains all of the genetic information required for its infection cycle as it readily replicated in cowpea protoplasts and systemically infected vicia faba seedlings that were biolistically inoculated using gold particles coated wit ... | 1999 | 10489354 |
| aphids, predators and parasitoids. | a number of studies have demonstrated the role of herbivore-induced release of plant volatiles in mediating foraging behaviour of aphid parasitoids, particularly with the parasitoid aphidius ervi, its aphid host acyrthosiphon pisum and the aphid food plant vicia faba. these studies have shown that feeding by the aphid alters the composition of volatiles released by the plant and that these compounds act as synomones for the foraging parasitoid. of particular interest is the species-specificity o ... | 1999 | 10549548 |
| variability and parasitoid foraging efficiency: a case study of pea aphids and aphidius ervi. | when a parasitoid is searching for hosts, not all hosts are equally likely to be attacked. this variability in attack probability may affect the parasitoid functional response. using a collection of experiments, we quantified the functional response of aphidius ervi (hymenoptera: braconidae), an insect parasitoid of the pea aphid acyrthosiphon pisum (homoptera: aphididae). we measured variability in the number of hosts attacked by a foraging parasitoid both among plants and within plants. at the ... | 1999 | 10600611 |
| acetone preservation: a practical technique for molecular analysis. | in attempts to establish a convenient and reliable method for field collection and archival preservation of insects and their endosymbiotic microorganisms for molecular analysis, acetone, ethanol, and other organic solvents were tested for dna preservability of the pea aphid acyrthosiphon pisum and its intracellular symbiotic bacterium buchnera sp. after 6 months' storage, not only the band of high-molecular-size dna but also the bands of rrna were well preserved in acetone, ethanol, 2-propanol, ... | 1999 | 10620236 |
| the influence of parasitism on wing development in male and female pea aphids. | wing formation in presumptive alate morphs (virginoparae and males) was observed for the pea aphid, acyrthosiphon pisum, exposed to attack by the parasitoid, aphidius ervi, at different stages of host development. morphological abnormalities in parasitized aphids such as complete apterization (development of a wingless form), formation of rudimentary wing buds, and deformed wings indicate a possible disruption of the endocrine system. changes in the body shape and the number of olfactory seconda ... | 2000 | 10802097 |
| host castration by aphidius ervi venom proteins. | the braconid aphidius ervi haliday (hymenoptera, braconidae) is an endophagous parasitoid of the pea aphid, acyrthosiphon pisum (harris) (homoptera, aphididae). parasitized host aphids show different degrees of castration, a response that is total when parasitoid oviposition takes place in first instar hosts. deleterious effects on the host reproductive system are already evident by 24h following parasitization, before egg hatching. the effect of parasitoid venom on a. pisum ovaries has been stu ... | 2000 | 10802117 |
| the latent period of pea-enation mosaic virus in the pea aphid, acyrthosiphon pisum (harris)--an approach to its estimation. | | 1965 | 14277086 |
| developmental origin and evolution of bacteriocytes in the aphid-buchnera symbiosis. | symbiotic relationships between bacteria and insect hosts are common. although the bacterial endosymbionts have been subjected to intense investigation, little is known of the host cells in which they reside, the bacteriocytes. we have studied the development and evolution of aphid bacteriocytes, the host cells that contain the endosymbiotic bacteria buchnera aphidicola. we show that bacteriocytes of acyrthosiphon pisum express several gene products (or their paralogues): distal-less, ultrabitho ... | 2003 | 14551917 |
| spiroplasma symbiont of the pea aphid, acyrthosiphon pisum (insecta: homoptera). | from a laboratory strain of the pea aphid, acyrthosiphon pisum, we discovered a previously unknown facultative endosymbiotic bacterium. molecular phylogenetic analysis based on 16s ribosomal dna revealed that the bacterium is a member of the genus spiroplasma. the spiroplasma organism showed stable vertical transmission through successive generations of the host. injection of hemolymph from infected insects into uninfected insects established a stable infection in the recipients. the spiroplasma ... | 2001 | 11229923 |
| independent origins and horizontal transfer of bacterial symbionts of aphids. | many insect groups have obligate associations with primary endosymbionts: mutualistic bacteria that are maternally transmitted and derived from an ancient infection. often, the same insects are hosts to 'secondary' bacterial symbionts which are maternally transmitted but relatively labile within host lineages. to explore the dynamics of secondary symbiont associations in aphids, we characterized bacteria infecting 15 species of macrosiphine aphids using dna sequencing, diagnostic polymerase chai ... | 2001 | 11251800 |
| rickettsia associated with male-killing in a buprestid beetle. | many populations of the buprestid leaf-mining beetle, brachys tessellatus, from central south carolina, usa, show highly skewed sex ratios, ranging from 1.3 to 6.0 females per male. we have identified a rickettsia bacterium that is associated with sex ratio distortion (srd) and selective killing of male embryos in b. tessellatus. molecular assays of infection by this bacterium are highly associated with srd within families, and treatment with an antibiotic (tetracycline) increases the number of ... | 2001 | 11520350 |
| plant waxy bloom on peas affects infection of pea aphids by pandora neoaphidis. | this study examined the effects of the surface wax bloom of pea plants, pisum sativum, on infection of pea aphids, acyrthosiphon pisum, by the fungal pathogen pandora neoaphidis. in prior field surveys, a higher proportion of p. neoaphidis-killed pea aphids (cadavers) had been observed on a pea line with reduced wax bloom, as compared with a sister line with normal surface wax bloom. laboratory bioassays were conducted in order to examine the mechanisms. after plants of each line infested with a ... | 2003 | 14726238 |
| changing partners in an obligate symbiosis: a facultative endosymbiont can compensate for loss of the essential endosymbiont buchnera in an aphid. | almost all aphids harbour an endosymbiotic bacterium, buchnera aphidicola, in bacteriocytes. buchnera synthesizes essential nutrients and supports growth and reproduction of the host. over the long history of endosymbiosis, many essential genes have been lost from the buchnera genome, resulting in drastic genome reduction and the inability to live outside the host cells. in turn, when deprived of buchnera, the host aphid suffers retarded growth and sterility. buchnera and the host aphid are ofte ... | 2003 | 14728775 |
| clonal variation and covariation in aphid resistance to parasitoids and a pathogen. | the potential rate of evolution of resistance to natural enemies depends on the genetic variation present in the population and any trade-offs between resistance and other components of fitness. we measured clonal variation and covariation in pea aphids (acyrthosiphon pisum) for resistance to two parasitoid species (aphidius ervi and a. eadyi) and a fungal pathogen (erynia neoaphidis). we found significant clonal variation in resistance to all three natural enemies. we tested the hypothesis that ... | 2001 | 11681735 |
| comparison of complete nucleotide sequences of genomic rnas of four soybean dwarf virus strains that differ in their vector specificity and symptom production. | soybean dwarf virus (sbdv) is divided into four strains, namely ys, yp, ds and dp. ys and yp cause yellowing in soybeans, while ds and dp cause dwarfing. ys and ds are transmitted by aulacorthum solani, while yp and dp are transmitted by acyrthosiphon pisum. to clarify the taxonomic relationship between the four strains and to classify sbdv into an appropriate genus in the luteoviridae, we determined the complete nucleotide sequences of genomic rnas of four isolates belonging to each of the stra ... | 2001 | 11722012 |
| an experimental validation of orphan genes of buchnera, a symbiont of aphids. | although buchnera sp. aps, an intracellular symbiont of pea aphids, is a close relative of escherichia coli, its genome has been extensively modified because of its prolonged intracellular life. in our previous studies on the buchnera genome, computer analysis predicted three "orphan" genes, yba2, yba3, and yba4, which are open reading frames (orfs) with no homologs in the database. in this paper, we successfully validated all these orphan genes by rt-pcr and northern hybridization. the present ... | 2002 | 11890702 |
| the evolutionary fate of nonfunctional dna in the bacterial endosymbiont buchnera aphidicola. | reduction of the genome size in endosymbiotic bacteria is the main feature linked to the adaptation to a host-associated lifestyle. we have analyzed the fate of the nonfunctional dna in buchnera aphidicola, the primary endosymbiont of aphids. at least 164 gene losses took place during the recent evolution of three b. aphidicola strains, symbionts of the aphids acyrthosiphon pisum (bap), schizaphis graminum (bsg), and baizongia pistacia (bbp). a typical pattern starts with the inactivation of a g ... | 2004 | 15317875 |
| estimating population size and transmission bottlenecks in maternally transmitted endosymbiotic bacteria. | many species of bacterial endosymbionts are acquired by animal hosts before birth, through direct transmission from mothers to eggs or embryos. this vertical transmission imposes a reduction in numbers or "bottleneck," and the size of this bottleneck affects the population structure and evolution of symbiotic lineages. we have estimated the size of the transmission bottleneck in buchnera, the bacterial symbiont of aphids, using basic light and electron microscopy techniques. by serial-sectioning ... | 2002 | 12087426 |
| 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 |
| influence of temperature on pea aphid acyrthosiphon pisum (hemiptera: aphididae) resistance to natural enemy attack. | the ability to resist or avoid natural enemy attack is a critically important insect life history trait, yet little is understood of how these traits may be affected by temperature. this study investigated how different genotypes of the pea aphid acyrthosiphon pisum harris, a pest of leguminous crops, varied in resistance to three different natural enemies (a fungal pathogen, two species of parasitoid wasp and a coccinellid beetle), and whether expression of resistance was influenced by temperat ... | 2002 | 12191444 |
| probiotic effect of lactobacillus sp. ds-12 in flounder (paralichthys olivaceus). | pea aphids were reared aseptically in the laboratory and fed on strains of erwinia aphidicola, erwinia herbicola, klebsiella pneumoniae, escherichia coli and bacterium w, an aphid enterobacterium, by mixing with a synthetic diet to determine whether these bacteria have pathogenicity to the insect. it turned out that er. aphidicola and er. herbicola grew in aphid gut, while k. pneumoniae, es. coli and bacterium w were effectively eliminated. in the case of er. aphidicola, ingestion of a single do ... | 1997 | 12501308 |
| effect of spatial heterogeneity on the role of coccinella septempunctata as an intra-guild predator of the aphid pathogen pandora neoaphidis. | the foraging behavior of starved and non-starved adult and larval coccinella septempunctata on groups of plants in the presence of pandora neoaphidis-infected acyrthosiphon pisum, uninfected aphids or a mixture of these two prey types was compared. in general results of these studies confirmed the results of previous work comparing foraging behavior on a smaller spatial scale in petri dishes. however, behaviors were modified in response to spatial complexity, prey quality, and the host plant. st ... | 2003 | 12623308 |
| rickettsia symbiont in the pea aphid acyrthosiphon pisum: novel cellular tropism, effect on host fitness, and interaction with the essential symbiont buchnera. | in natural populations of the pea aphid acyrthosiphon pisum, a facultative bacterial symbiont of the genus rickettsia has been detected at considerable infection frequencies worldwide. we investigated the effects of the rickettsia symbiont on the host aphid and also on the coexisting essential symbiont buchnera. in situ hybridization revealed that the rickettsia symbiont was specifically localized in two types of host cells specialized for endosymbiosis: secondary mycetocytes and sheath cells. e ... | 2005 | 16000822 |
| a novel computerised image analysis method for the measurement of production of conidia from the aphid pathogenic fungus erynia neoaphidis. | a semi-automated method has been developed for the quantification and measurement of conidia discharged by the aphid pathogen erynia neoaphidis. this was used to compare conidiation by e. neoaphidis-mycosed pea aphid cadavers, mycelial plugs cut from agar plates, mycelial pellets from shake flasks and by mycelial pellets from different phases of liquid batch fermenter culture. aphid cadavers discharged significantly more and significantly smaller conidia than plugs or pellets. the volume of coni ... | 2003 | 12644230 |
| extraordinary proliferation of microorganisms in aposymbiotic pea aphids, acyrthosiphon pisum. | aposymbiotic pea aphids, which were deprived of their intracellular symbiotic bacterium, buchnera, exhibit growth retardation and no fecundity. high performance liquid chromatographic (hplc) analysis revealed that these aposymbiotic aphids, when reared on broad bean plants, accumulated a large amount of histamine. to assess the possibility of extraordinary proliferation of microorganisms other than buchnera, we enumerated eubacteria and fungi in aphids using the real-time quantitative pcr method ... | 2003 | 12676551 |
| characterization of a high-affinity binding site for the pea albumin 1b entomotoxin in the weevil sitophilus. | the toxicity of the pea albumin 1b (pa1b), a 37 amino-acid peptide extracted from pea seeds, for cereal weevils (sitophilus oryzae, sitophilus granarius and sitophilus zeamais) was recently discovered. the mechanism of action of this new entomotoxin is still unknown and potentially involves a target protein in the insect tissues. this work describes the characterization of a high-affinity binding site for pa1b in a microsomal fraction of sitophilus spp. extracts. purified pa1b was labeled to a h ... | 2003 | 12755698 |
| host regulation effects of ovary fluid and venom of aphidius ervi (hymenoptera: braconidae). | the host regulation effects of venom and ovary fluid of the endophagous braconid aphidius ervi haliday on the pea aphid, acyrthosiphon pisum (harris), have been studied. extracts of ovaries and of venom glands were injected into nonparasitized 4th instar pea aphids, both separately and mixed. aphids treated with parasitoid material died as 4th instars, often showing developmental arrest. in contrast, control aphids that received an injection of pringle's saline solution regularly moulted to the ... | 1998 | 12769873 |
| host cell allometry and regulation of the symbiosis between pea aphids, acyrthosiphon pisum, and bacteria, buchnera. | the symbiotic bacteria buchnera in aphids are borne in cells, called bacteriocytes, in the insect haemocoel. the number and median volume of bacteriocytes in pre-reproductive adult insects varied significantly among 14 parthenogenetic clones of the pea aphid acyrthosiphon pisum. after logarithmic transformation of the data, the relationship of both number and median volume of bacteriocytes with aphid weight for the clones could be described by common regression lines with slopes significantly gr ... | 1998 | 12769945 |
| pea aphid clonal resistance to the endophagous parasitoid aphidius ervi. | the physiological mechanism of resistance to the endophagous braconid aphidius ervi haliday (hymenoptera, braconidae) by a pink clone (pc) of acyrthosiphon pisum (harris) (homoptera, aphididae) has been investigated. comparative data on parasitoid development and associated host biochemical changes in the resistant pc aphids and in a susceptible green clone (gc) of a. pisum are reported. when the pc aphids were attacked as early 4th instars, the developing parasitoid larvae showed a strongly red ... | 2002 | 12770044 |
| 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 |
| metabolic and symbiotic interactions in amino acid pools of the pea aphid, acyrthosiphon pisum, parasitized by the braconid aphidius ervi. | aphidius ervi haliday (hymenoptera, braconidae) is an endophagous parasitoid of the pea aphid, acyrthosiphon pisum (harris) (homoptera, aphididae). this parasitoid strongly redirects host reproduction and metabolism to favour nutrition and development of its juvenile stages. parasite-regulated biosynthesis and mobilization of nitrogen metabolites determine a significant increase of host nutritional suitability. the aim of the present study was mainly to investigate the temporal changes of a. pis ... | 2002 | 12770078 |
| provision of riboflavin to the host aphid, acyrthosiphon pisum, by endosymbiotic bacteria, buchnera. | differential cdna display and quantitative rt-pcr suggested that the riboflavin synthase complex of the aphid endosymbiont, buchnera, is active only when the symbiotic system is maintained and well organized in young hosts. since this finding suggested the provision of riboflavin by buchnera, we examined the effect of dietary riboflavin on the performance of symbiotic and aposymbiotic aphids using chemically-defined diets. our results indicate: (1) dietary riboflavin is slightly detrimental to y ... | 1999 | 12770389 |
| 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 |
| xerocomus chrysenteron lectin: identification of a new pesticidal protein. | xerocomus chrysenteron is an edible mushroom with insecticidal properties. in an earlier work, we found that proteins are responsible for this toxicity. here we describe the purification of a approximately 15 kda lectin, named xcl, from the mushroom. its cdna and gdna were cloned by pcr strategies and a recombinant form was expressed in escherichia coli. sequence alignments and sugar specificity showed that this protein is the third member of a new saline-soluble lectin family present in fungi. ... | 2003 | 12787928 |
| elucidation of the transmission patterns of an insect-borne bacterium. | quantitative data on modes of transmission are a crucial element in understanding the ecology of microorganisms associated with animals. we investigated the transmission patterns of a gamma-proteobacterium informally known as pea aphid bemisia-like symbiont (pabs), also known as t-type, which is widely but not universally distributed in natural populations of the pea aphid, acyrthosiphon pisum. the vertical transmission of pabs to asexual and sexual morphs and sexually produced eggs was demonstr ... | 2003 | 12902222 |
| host-based divergence in populations of the pea aphid: insights from nuclear markers and the prevalence of facultative symbionts. | in north america, the pea aphid acyrthosiphon pisum encompasses ecologically and genetically distinct host races that offer an ideal biological system for studies on sympatric speciation. in addition to its obligate symbiont buchnera, pea aphids harbour several facultative and phylogenetically distant symbionts. we explored the relationships between host races of a. pisum and their symbiotic microbiota to gain insights into the historical process of ecological specialization and symbiotic acquis ... | 2003 | 12964998 |
| 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 |
| diversity of bacteria associated with natural aphid populations. | the bacterial communities of aphids were investigated by terminal restriction fragment length polymorphism and denaturing gradient gel electrophoresis analysis of 16s rrna gene fragments generated by pcr with general eubacterial primers. by both methods, the gamma-proteobacterium buchnera was detected in laboratory cultures of six parthenogenetic lines of the pea aphid acyrthosiphon pisum and one line of the black bean aphid aphis fabae, and one or more of four previously described bacterial tax ... | 2003 | 14660369 |
| facultative symbionts are associated with host plant specialization in pea aphid populations. | the pea aphid, acyrthosiphon pisum, shows significant reproductive isolation and host plant specialization between populations on alfalfa and clover in new york. we examine whether specialization is seen in pea aphids in california, and whether fitness on alternative host plants is associated with the presence of bacterial symbionts. we measured the fitness of alfalfa- and clover-derived aphids on both types of plants and found no evidence for specialization when all aphid lineages were consider ... | 2003 | 14667385 |
| the population genetics of a biological control introduction: mitochondrial dna and microsatellie variation in native and introduced populations of aphidus ervi, a parisitoid wasp. | introductions of biological control agents may cause bottlenecks in population size despite efforts to avoid them. we examined the population genetics of aphidius ervi (hymenoptera: braconidae), a parasitoid that was introduced to north america from western europe in 1959 to control pea aphids. to explore the phylogeographical relationships of a. ervi we sequenced 1249 bp of mitochondrial dna (mtdna) from 27 individuals from the native range and 51 individuals from the introduced range. most ind ... | 2004 | 14717891 |
| 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 |
| rapid quantification of juvenile hormones and their metabolites in insect haemolymph by liquid chromatography-mass spectrometry (lc-ms). | a simple, fast and sensitive method was developed for routine determination of juvenile hormone (jh), jh diols and jh acids in insect haemolymph, by liquid chromatography-mass spectrometry (lc-ms). sample clean-up involves the precipitation of proteins by methanol/isooctane (1:1, v/v), centrifugation and partial evaporation of the organic solvents. since jh is bound to a carrier protein in the haemolymph, a binding protein (bp) assay was performed to ensure jh is removed during precipitation. th ... | 2004 | 15057500 |
| 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 |
| responses to ozone of insects feeding on a crop and a weed species. | the influence of ozone on insect herbivore growth and population development was investigated. fumigation of both pea (pisum sativum l.) and dock (rumex obtusifolius l.) at a range of o(3) concentrations between 21-206 nl litre(-1) produced changes in mean relative growth rates of the aphids acyrthosiphon pisum harris and aphis rumicis l. of between 24 and -6% relative to controls. however, there was no evidence of a dose-related response to o(3) fumigation and no clear differences in aphid resp ... | 1989 | 15092338 |
| the role of semiochemicals in the avoidance of the seven-spot ladybird, coccinella septempunctata, by the aphid parasitoid, aphidius ervi. | the role of semiochemicals in mediating intraguild interactions between the seven-spot ladybird, coccinella septempunctata, and the aphid parasitoid, aphidius ervi, was investigated. female parasitoids avoided leaves visited by c. septempunctata adults and larvae during the previous 24 hr. ethanol extracts of c. septempuntata adults and larvae also induced avoidance responses by a. ervi. two of the hydrocarbons identified by gas chromatography (gc) and coupled gc-mass spectrometry (gc-ms), n-tri ... | 2004 | 15303317 |
| 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 |
| diversity and geographic distribution of secondary endosymbiotic bacteria in natural populations of the pea aphid, acyrthosiphon pisum. | in addition to the essential intracellular symbiotic bacterium buchnera, several facultative endosymbiotic bacteria called collectively secondary symbionts (s-symbionts) have been identified from the pea aphid acyrthosiphon pisum. we conducted an extensive and systematic survey of s-symbionts in japanese local populations of a. pisum using a specific pcr detection technique. five s-symbionts of a. pisum, pass, paus, pabs, rickettsia and spiroplasma, and two facultative endosymbionts universally ... | 2002 | 12296954 |
| 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 |
| plant-to-plant communication mediating in-flight orientation of aphidius ervi. | broad bean plants (viciafaba) infested by the pea aphid, acyrthosiphonpisum, play akey role in the in-flightorientation of the parasitoidaphidius ervi, by producing host-induced synomones (his). these volatiles are herbivore-specific and are systemically released from insect-free parts of an infested plant, suggesting the existence of an elicitor circulating throughout the plant. this study was designed to investigate whether the plant metabolic changes, leading to his biosynthesis and emission, ... | 2002 | 12449500 |
| erwinia aphidicola, a new species isolated from pea aphid, acyrthosiphon pisum. | five strains of gram-negative, oxidase-negative, facultatively anaerobic, fermentative, motile, rod-shaped bacterium with the general characteristics of the family enterobacteriaceae were isolated from the gut of multiple specimens of the pea aphid. all the strains caused aphid mortality when ingested by insects via a synthetic diet. the results of biochemical tests showed that these strains are most related to erwinia herbicola and pantoea agglomerans. according to dna-dna hybridization, the fi ... | 1997 | 12501306 |
| regulation of transcription in a reduced bacterial genome: nutrient-provisioning genes of the obligate symbiont buchnera aphidicola. | buchnera aphidicola, the obligate symbiont of aphids, has an extremely reduced genome, of which about 10% is devoted to the biosynthesis of essential amino acids needed by its hosts. most regulatory genes for these pathways are absent, raising the question of whether and how transcription of these genes responds to the major shifts in dietary amino acid content encountered by aphids. using full-genome microarrays for b. aphidicola of the host schizaphis graminum, we examined transcriptome respon ... | 2005 | 15937185 |
| response of the entomopathogenic fungus pandora neoaphidis to aphid-induced plant volatiles. | we used a model plant-aphid system to investigate whether the aphid-specific entomopathogenic fungus pandora neoaphidis responds to aphid-induced defence by the broad-bean plant, vicia faba. laboratory experiments indicated that neither in vivo sporulation, conidia size nor the in vitro growth of p. neoaphidis was affected by acyrthosiphon pisum-induced v. faba volatiles. the proportion of conidia germinating on a. pisum feeding on previously damaged plants was significantly greater than on aphi ... | 2005 | 16005016 |
| 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 |
| pandora neoaphidis transmission and aphid foraging behaviour. | pandora neoaphidis is an aphid-specific entomopathogen that produces infective conidia. as aphid movement increases, so does the likelihood of contact with conidia. volatile distress signals released in response to aphid infestation as an indirect defence against herbivory may affect aphid foraging and, therefore, the fungus-aphid interaction. in this study, two different methods were used to investigate the effect of plant volatiles and p. neoaphidis-sporulating cadavers on (1) the colonisation ... | 2005 | 16039666 |
| 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 |