Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| reproductive strategy of winged and wingless morphs of the aphids sitobion avenae and metopolophium dirhodum. | the reproduction of apterous and alate morphs of the aphids sitobion avenae and metopolophium dirhodum is compared on the basis of fecundity in 5- and 10-day periods of adult life. apterae of both species are consistently more fecund than alatae of comparable weight, producing about three more nymphs on average in any 5-day period. the reproductive differences are related to the number and quality of embryos at eclosion and to ovulation rates, both of which in turn appear to be linked to wing-mu ... | 1977 | 848782 |
| [a comparative study of the substrate and inhibitor specificity of the glutathione transferase from the spring grain aphid (schizaphis gramina rond.) and from rat liver]. | kinetic parameters of 9 substrates interaction with glutathione transferase (gst) from spring grain aphid and rat were studied. the most significant difference in vmax values was noticed for 4-nitropyridine-n-oxide (6 times higher for aphid) and ethacrynic acid (7 times higher for rat). km values were practically in all cases higher for aphid gst as compared to rat gst. new class of effectors of gst suggested by us, that is azimines (2 series), was used for the inhibitor analysis. gst interactio ... | 1992 | 1302416 |
| simulation modelling of the population dynamics of cereal aphids. | a simulation model explaining the population dynamics of the grain aphid (sitobion avenae), a serious pest of wheat in western europe, is described. the model includes the effects of crop development and some natural enemies on the biology of the aphid. it is concluded that although much of the population dynamics of the aphid, especially in relation to its host plant, is now well understood, many uncertainties still remain concerning natural enemies. as these organisms seem able to prevent cere ... | 1985 | 3840702 |
| entomophthora infecting the cereal aphids metapolophium dirhodum and sitobion avenae. | 1971 | 5092836 | |
| [effect of organophosphorus inhibitors, lupinine and epilupinine derivatives, on mammalian and arthropod cholinesterases]. | studies have been made on the effect of organophosphorus inhibitors on cholinesterases (che) from mammals (human and rabbit erythrocytes, mice brain) and arthropods (fly, spring grain aphid, rice weevil and spider tick). organophosphorus inhibitors were presented by dialkylthiophosphates which contained normal or branching alkyls in the phosphoryl part of their molecule and lupinine or epilupinine residue in the other part of the latter. increasing the length of alkyl in lupinine derivatives inc ... | 1980 | 7405439 |
| geographic and microgeographic genetic differentiation in two aphid species over southern england using the multilocus (gata)4 probe. | samples of the grain aphid sitobion avenae (f.) and the rose-grain aphid metopolophium dirhodum (walker) were collected in late march from wheat fields and adjacent road-side grasses at a number of locations in southern england. unparasitized aphids were dna fingerprinted using the multilocus (gata)4 probe. over all locations, the fingerprints of individual s. avenae caught in wheat had lower overall average distances of band migration (adbm) and shared a higher proportion of bands, than fingerp ... | 1995 | 7663754 |
| an analysis of secondary spread by putative clones of sitobion avenae within a hampshire wheat field using the multilocus (gata)4 probe. | grain aphids (sitobion avenae (f.)) were collected from forty-four wheat ears in a hampshire field at three times during the growing season. on each occasion, individual aphids were profiled using the multilocus (gata)4 probe. during the full head emergence and full anthesis growth stages of wheat, each ear generally supported a genetically distinguishable aphid colony which consisted of genetically indistinguishable individuals (putative clones). this information strongly suggests that individu ... | 1994 | 7704309 |
| spatial and temporal genetic variation in british field populations of the grain aphid sitobion avenae (f.) (hemiptera: aphididae) studied using rapd-pcr. | the grain aphid sitobion avenae (f.) was collected from winter wheat and adjacent cocksfoot grass at two locations in southern england and at four times in the year (april-july). genetic variation between individual aphids was then investigated using random amplified polymorphic dna polymerase chain reaction. individuals caught in wheat and cocksfoot during april provided very different and highly diagnostic banding patterns that were independent of location. this host-based genetic differentiab ... | 1995 | 8587889 |
| 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 |
| two distinct mechanisms regulate luteovirus transmission efficiency and specificity at the aphid salivary gland. | barley yellow dwarf luteovirus (bydv) particles are transmitted by aphids in a species-specific manner. transmission to plants requires that the virus particles be transported across the basal lamina and plasmalemma of the accessory salivary gland (asg). to characterize the role of the asg basal lamina in regulating bydv transmission, five aphid species were microinjected with purified new york isolates bydv-pav or -rpv. both viruses associated specifically only with the asg basal lamina. the ab ... | 1997 | 9049397 |
| [a comparative study of the cholinesterase and carboxylesterase sensitivities of mammals and arthropods to new phenyl and glycidyl esters of dialkyl thiophosphoric acid]. | the antienzymic activities of 14 organophosphorous compounds, the derivatives of dialkyl thiophosphoric acid, towards the acetylcholinesterase (ache), butyrylcholinesterase (buche) and carboxylesterase (ce) from the spring grain aphid and mammals were investigated. the dependence of inhibitory activity of the compounds on their alkyl radical length was shown to be different for the ache from the aphid and man. some less pronounced differences in this dependence were revealed between the buches f ... | 1996 | 9054171 |
| genotypic variation among different phenotypes within aphid clones. | most aphid species hemiptera: aphididae are parthenogenetic between periods of sexual reproduction. they are also highly polyphenic, with different adult morphs occurring in the life cycle, piz. winged, wingless, asexual and sexual. it is assumed that aphids born in a parthenogenetic clonal lineage are genetically identical regardless of the final adult form with the exception of sexual forms). using the randomly amplified polymorphic dna-polymerase chain reaction (rapd-pcr) we have found that d ... | 1997 | 9178543 |
| genetic structure of an aphid studied using microsatellites: cyclic parthenogenesis, differentiated lineages and host specialization. | in a previous study, samples of the grain aphid sitobion avenae (f.) were collected from wheat and adjacent cocksfoot hosts in a population thought to be primarily parthenogenetic, and dna from individual aphids was analysed with a multilocus technique. here we have applied single-locus microsatellites and a mitochondrial dna marker to a subset of the same dna extracts, and have made several additional inferences about important genetic and population processes in s. avenae. microsatellite analy ... | 1997 | 9394464 |
| genetic variation within a parthenogenetic lineage. | a clone of the grain aphid sitobion avenae f. was maintained parthenogenetically over thirty-two generations (n = 344) in a constant environment: a new generation being set up by a female selected at random from the preceding generation. genomic dna from individual aphids was screened for genetic stability using rapd-pcr with a previously tested ten-mer primer. a putative germ-line mutation was noted in generation 14 and somatic mutations were noted in generations 12, 25, 27 and 29. there were n ... | 1998 | 9723871 |
| reproductive mode and population genetic structure of the cereal aphid sitobion avenae studied using phenotypic and microsatellite markers. | as french populations of the aphid sitobion avenae exhibit a range of reproductive modes, this species provides a good opportunity for studying the evolution of breeding system variation. the present analysis combined ecological and genetic investigations into the spatial distribution of variation in reproductive mode. reproductive mode was characterized in 277 lineages of s. avenae from france, and these aphids were scored for five microsatellite loci. the analyses revealed strong geographical ... | 1999 | 10327655 |
| overwintering strategies and cold hardiness of two aphid parasitoid species (hymenoptera: braconidae: aphidiinae). | the role of winter diapause in two aphid parasitoid species, aphidius ervi haliday and aphidius rhopalosiphi destefani-peres (hymenoptera: braconidae: aphidiinae), in host synchronization and the induction of cold hardiness was investigated. parasitoids were reared during three successive generations on sitobion avenae fabricius, at 15 degrees c under a photoperiod of 9 h light 15 h dark. although these conditions are known to be strongly diapause inducing, neither parasitoids showed an incidenc ... | 2000 | 10742515 |
| seasonal dynamics of cereal aphids on russian wheat aphid (homoptera: aphididae) susceptible and resistant wheats. | field experiments were conducted in 1997 and 1998 to evaluate the impact of resistance to russian wheat aphid, diuraphis noxia (mordvilko), on the cereal aphid complex in wheat. two spring wheats were planted: the variety "centennial" (russian wheat aphid susceptible) and the advanced line ido488 (russian wheat aphid resistant). ido488 incorporates the resistance found in pi 294994 into a centennial background. field plots were artificially infested with adult d. noxia and sampled weekly. the mo ... | 2000 | 10902358 |
| evidence for predominant clones in a cyclically parthenogenetic organism provided by combined demographic and genetic analyses. | aphids are particularly interesting models in the study of genetic and demographic components of plant adaptation because of their breeding system which combines parthenogenesis and sexual reproduction (i.e. cyclical parthenogenesis), and the frequent emergence of host-adapted races reported in this group. in this paper, patterns of host adaptation were assessed on local populations of the aphid sitobion avenae by following their demographic and genetic structure in a maize field for two consecu ... | 2000 | 11123618 |
| superparasitism limitation in an aphid parasitoid: cornicle secretion avoidance and host discrimination ability. | superparasitism avoidance by the endoparasitoid aphidius rhopalosiphi de stefani perez on the grain aphid, sitobion avenae was studied. experiments were carried out in which aphids were exposed to two consecutive attacks by parasitoids. results showed that superparasitism avoidance in a. rhopalosiphi was mediated by two successive stimuli whose effectiveness depended on the time interval between attacks. for short time intervals (<16 h), host rejections were mainly associated with the presence o ... | 2001 | 11166298 |
| seasonal abundance of aphids (homoptera: aphididae) in wheat and their role as barley yellow dwarf virus vectors in the south carolina coastal plain. | aphid (homoptera: aphididae) seasonal flight activity and abundance in wheat, triticum aestivum l., and the significance of aphid species as vectors of barley yellow dwarf virus were studied over a nine-year period in the south carolina coastal plain. four aphid species colonized wheat in a consistent seasonal pattern. greenbug, schizaphis graminum (rondani), and rice root aphid, rhopalosiphum rufiabdominalis (sasaki), colonized seedlingwheat immediately after crop emergence, with apterous colon ... | 2001 | 11332833 |
| vector specificity of barley yellow dwarf virus (bydv) transmission: identification of potential cellular receptors binding bydv-mav in the aphid, sitobion avenae. | two proteins (sam35 and sam50) isolated from head tissues of the aphid vector, sitobion avenae, were identified as potential receptors for barley yellow dwarf virus mav isolate (luteoviridae) based on mav virus overlay assays and immunoblots of urea sds 2-d gels. an anti-idiotypic antibody (mav4 anti-id) that mimics an epitope on mav virions and competes with mav in antibody binding assays also bound to sam50 and sam35 and to six additional proteins including a groel homolog. no mav-binding prot ... | 2001 | 11448166 |
| electrophoretic analysis of albumins and globulins isolated from the winter triticale of different resistance to the grain aphid. | 2001 | 11544647 | |
| secondary predation: quantification of food chain errors in an aphid-spider-carabid system using monoclonal antibodies. | "secondary predation" occurs when one predator feeds on a second predator, which has in turn eaten a target prey. detection of prey remains within predators using monoclonal antibodies cannot distinguish between primary and secondary predation, potentially leading to quantitative and qualitative food chain errors. we report the first fully replicated experiments to measure secondary predation effects, using an aphid-spider-carabid system. aphids, sitobion avenae, were fed to spiders, lepthyphant ... | 2001 | 11555248 |
| [effects of volatiles from different trophic level on foraging behavior of aphidius avenae]. | the responses of female aphidius avenae to volatiles from undamaged wheat plant, sitobion avenae and rhopalosiphum padi, aphids-plant complexes and aphids damaged plant were investigated in wind tunnel and y-tube olfactometer. the volatiles from undamaged wheat plant, s. avenae and r. padi were much less attractive to a. avenae than those from aphids-plant complexes and aphids-damaged plant. although the parasitic rate was much lower, the r. padi-plant complexes and r. padi damaged plant were al ... | 2001 | 11758388 |
| association of insects and ergot (claviceps purpurea) in kentucky bluegrass seed production fields. | insects in kentucky bluegrass seed production fields in oregon, idaho, and washington were sampled just before harvest and their association with ergot conidia of claviceps purpurea fr. (tul.) was evaluated during 1996-1998. a diversity of insects was observed at all three locations. the most abundant beneficial insects collected with sweep nets were nysium spp., nabis spp., ichneumonid wasps, and hippodamia spp. the cranberry girdler, chrysoteuchia topiaria (zeller), was the only important pest ... | 2001 | 11777051 |
| relationships between sulfonylurea herbicide treatment of host plants and the performance of herbivorous insects. | previous work had shown that the sulfonylurea herbicide chlorsulfuron affected the survival of a herbivorous insect species dwelling on a sub-lethally exposed host plant. further experiments have been conducted to establish whether this negative effect was a single occurrence characteristics for the specific insect-plant interaction and the specific herbicide tested. three insect-plant interactions were tested for the effects of selected sulfonylurea herbicides, i.e. metsulfuron-methyl, chlorsul ... | 2001 | 11802605 |
| temporal variation of rapd-pcr phenotype composition of the grain aphid sitobion avenae (hemiptera: aphididae) on wheat: the role of hydroxamic acids. | hydroxamic acids (hx) contained in wheat are active mutagens which play an important role in the defence of the plant against aphids. random amplified polymorphic dna-polymerase chain reaction (rapd-pcr) dominant markers were used to assess genetic variability in the aphid sitobion avenae (fabricius) in relation to hydroxamic acid levels in their host-plants. colonies of aphids belonging to a single rapd-pcr profile were grown on different host-plants differing in their hx content under greenhou ... | 2002 | 12020359 |
| host-based genotype variation in insects revisited. | elucidation of the genetic variability of a model insect species, the grain aphid, sitobion avenae (fabricius), a predominantly asexual herbivore within the temperate agro-ecosystem tested, was initiated using molecular dna markers (rapds). this revealed genetic profiles that appeared related to host adaptation at the specific level amongst the natural populations colonizing different grasses and cereals (poaceae) within the same geographic location. these profiles were recorded either as 'speci ... | 2002 | 12020375 |
| l-ascorbic acid is accumulated in source leaf phloem and transported to sink tissues in plants. | l-ascorbic acid (asa) was found to be loaded into phloem of source leaves and transported to sink tissues. when l-[(14)c]asa was applied to leaves of intact plants of three different species, autoradiographs and hplc analysis demonstrated that asa was accumulated into phloem and transported to root tips, shoots, and floral organs, but not to mature leaves. asa was also directly detected in arabidopsis sieve tube sap collected from an english green aphid (sitobion avenae) stylet. feeding a single ... | 2002 | 12376632 |
| two-dimensional electrophoresis of proteins discriminates aphid clones of sitobion avenae differing in bydv-pav transmission. | aset of 39 f1 sitobion avenae clones was obtained by selfing a poorly efficient bydv-pav vector clone. these clones were genetically typed by 11 microsatellite loci, and tested for bydv-pav4 transmission to barley. the 39 clones displayed a continuum in transmission percentages, from 0% to 88% with a significant clone effect. from this set, two highly efficient (hev) and two poorly efficient (pev) vectoring clones were more precisely characterized for transmission of two other pav isolates. the ... | 2002 | 12376751 |
| migration and genetic structure of the grain aphid (sitobion avenae) in britain related to climate and clonal fluctuation as revealed using microsatellites. | genetic structuring of populations reflects the interaction of genetic drift, mutation, migration and selection, with influences from life history. aphids are interesting in this regard as they have the potential for unusually high levels of dispersal and natural selection, which typically counter each other. in the present study, winged grain aphids sitobion avenae (f.) were collected in four 12.2-m high suction traps along a north-south transect in britain in order to eliminate sampling bias f ... | 2003 | 12492875 |
| glutenin and gliadin contents of flour derived from wheat infested with different aphid species. | aphid feeding in cereals results in both quantitative and qualitative yield losses; moreover aphid-transmitted viruses are responsible for other quantitative and qualitative damage so that direct or indirect effects of aphid infection are always of interest. at the beginning of stem elongation, wheat plants were caged regardless of the presence or absence of indigenous cereal aphids. half of the caged plants were artificially infected with diuraphis noxia. the number of d noxia and rhopalosiphum ... | 2003 | 12701703 |
| predominance of sexual reproduction in romanian populations of the aphid sitobion avenae inferred from phenotypic and genetic structure. | models of coexistence of sexual and asexual lineages in aphids assume that obligate parthenogenetic lineages predominate in areas with mild winter climate because of their high reproductive output, while sexual lineages predominate in areas with severe winter because they produce eggs resistant to frost. to validate this hypothesis in natural conditions, the reproductive mode of populations of the aphid sitobion avenae was assessed in two very contrasting climatic situations, romania (severe win ... | 2003 | 12714986 |
| patterns of resistance to three cereal aphids among wheats in the genus triticum (poaceae). | forty-one accessions of wild and cultivated wheats belonging to 19 triticum species were tested in the field for resistance to three species of aphids, rhopalosiphum padi linnaeus, sitobion avenae fabricius and schizaphis graminum rondani. antibiotic resistance was estimated by the increase in biomass of aphids over 21 days on adult plants. overall resistance was estimated by the plant biomass lost due to aphid infestation. all three species of aphids survived and reproduced on all wheats, and r ... | 2003 | 12908918 |
| cis-jasmone treatment induces resistance in wheat plants against the grain aphid, sitobion avenae (fabricius) (homoptera: aphididae). | cis-jasmone is a plant volatile known to have roles as an insect semiochemical and in inducing plant defence. it was evaluated in laboratory and field trials for control of cereal aphids. in an olfactometer bioassay cis-jasmone was repellent to alatae of the grain aphid, sitobion avenae (fabricius) (homoptera: aphididae). moreover, wheat, triticum aestivum (l), seedlings sprayed with formulated cis-jasmone 24 h previously were less susceptible to attack by s. avenae than control plants. in field ... | 2003 | 12974355 |
| transmission of barley yellow dwarf virus by different forms of the apple grain aphid, rhopalosiphum fitchii (sand.). | 1960 | 14429045 | |
| [niches analysis of three aphid populations on spring sowing maize]. | systematic analysis of aphid populations and niches patterns on spring sowing maize was carried out during 1998-1999 in the suburbs of chongqing. the results indicated that there were three aphid populations rhopalosiphum maidis fitch., rhopalosiphum padi linn. and sitobion avenae fabricius distributed on the spring sowing maize. the mixed aphid populations traded off during the growth period of spring sowing maize, and two peaks of quantitative counts were shown at the mid and last ten days of ... | 2003 | 14733003 |
| seedling and adult plant resistance to sitobion avenae (hemiptera: aphididae) in triticum monococcum (poaceae), an ancestor of wheat. | cereal aphids are important pests of wheat, triticum aestivum l. and triticum durum desf. crop resistance is a desirable method for managing cereal aphids in central north america, where the dominant crop, spring-sown wheat, has a low value per unit area. a diploid ancestor of wheat, triticum monococcum l., is reported to be partially resistant to sitobion avenae (fabricius), the most damaging cereal aphid in the region. to identify potential sources of resistance, 42 accessions of t. monococcum ... | 2004 | 14972048 |
| tillage impacts cereal-aphid (homoptera: aphididae) infestations in spring small grains. | we compared infestation levels of cereal aphids (homoptera: aphididae) in spring-seeded wheat and barley grown with and without preplant tillage for 8 site yr in eastern south dakota. crop residue covered approximately 25% of the soil surface with preplant tillage, whereas without preplant tillage 50% or more of surface residue was conserved. rhopalosiphum padi (l.) comprised nearly 90% of all cereal aphids sampled, and r. maidis (fitch), schizaphis graminum (rondani), and sitobion avenae (f.) c ... | 2003 | 14977117 |
| wide dispersal of aphid-pathogenic entomophthorales among aphids relies upon migratory alates. | entomophthoralean mycoses are of general importance in the natural control of aphids, but mechanisms involved in their dissemination are poorly understood. despite several possible means of fungal survival, the dispersal of the mycoses in aphids has never been related to the flight of their migratory alates that are able to locate suitable host plants. in this study, aphid-pathogenic fungi proved to be widely disseminated among various aphids by their alates through migratory flight based on the ... | 2004 | 15049924 |
| cold shock injury and ecological costs of rapid cold hardening in the grain aphid sitobion avenae (hemiptera: aphididae). | the ability of first instar nymphs and newly moulted pre-reproductive adults of the grain aphid s. avenae to rapidly cold harden was investigated. when nymphs reared at 20 degrees c were transferred directly to -8 degrees c for 3 h, there was 18% survival. this exposure was selected as the discriminating temperature. maximum increases in survival were achieved by acclimating nymphs for 2 h at 0 degrees c and adults for 3 h at 0 degrees c, resulting in survival of 83% and 68%, respectively. cooli ... | 2004 | 15081820 |
| effect of aphid-infested plants on the host location and learning behaviour of the parasitoid aphelinus abdominalis. | aphelinus abdominalis dalman (hymenoptera: aphelinidae) is a generalist parasitoid of cereal (e.g. sitobion avenae) and greenhouse aphids (e.g. macrosiphum euphorbiae). it differs from aphidius spp. (hymenoptera: braconidae) by its robust constitution, longevity and its habit to use aphids not only as hosts for its progeny but also as prey (host feeding). in addition, a. abdominalis does not evoke aphidius-characteristic defence responses by attacked aphids as this wasp approaches its hosts very ... | 2003 | 15149107 |
| [dynamics of indole alkaloids in wheat varieties with various resistance to wheat aphid sitobion avenae]. | uv spectrometry measurement on the indole alkaloids (ia) contents of seven wheat varieties (kok1679, my295, li, han4564 and yanda1817, resistant to s. avenae; shaanximazha and lovrin10, susceptible to s. avenae) showed that during tillering and stem elongation stages, kok1679, my295 and li had a higher ia content (> 0.5 mg.g-1 fw); and during heading and anthesis stages, the penultimate leaves of all five resistant varieties contained higher ia (> 0.5 mg.g-1 fw). the ia content was lower in the ... | 2004 | 15228012 |
| evidence for gene flow and local clonal selection in field populations of the grain aphid (sitobion avenae) in britain revealed using microsatellites. | samples of the grain aphid, sitobion avenae (f.), a major european pest of cereals, were collected in june and july 1997 from fields sown with winter wheat in a rough transect south-west of rothamsted, uk. these aphids were genotyped at four microsatellite loci known from previous studies to be highly polymorphic. allelic frequencies were similar between samples collected in the fields and in the 12.2 m high suction trap at rothamsted, and there were many widespread genotypes (clones), providing ... | 2004 | 15241466 |
| sitobion avenae alatae infected by pandora neoaphidis: their flight ability, post-flight colonization, and mycosis transmission to progeny colonies. | epizootics caused by the obligate entomophthorales pathogen pandora neoaphidis may result from more than one possible means of fungal dissemination among host aphids, but we hypothesize that wide dispersal of the fungus is most likely to be associated with the flight behavior of migratory alates. we tested this hypothesis in a simulation experiment by assessing the flight capability of sitobion avenae alates infected with p. neoaphidis and the potential of their post-flight survival, colonizatio ... | 2004 | 15261776 |
| observation on the initial inoculum source and dissemination of entomophthorales-caused epizootics in populations of cereal aphids. | a total number of 1092 migratory alates were trapped from air in wheat grown area of yuanyang county, henan province from early april through may 2002 in order to confirm the source and dissemination of entomophthoralean inocula to cause epizootics of cereal aphids. those included 415 sitobion avenae, 642 rhopalosiphum padi, 22 metopolophium dirhodum, and 13 schizaphis graminum. the trapped alates were daily collected and individually reared for 7 days on wheat plants in laboratory. of those 341 ... | 2004 | 15382675 |
| [obtainment of transgenic wheat with the insecticidal lectin from snowdrop (galanthus nivalis agglutinin; gna) gene and analysis of resistance to aphid]. | snowdrop lectin (galanthus nivalis agglutinin; gna) is toxic to sap sucking injurious insects of homopteran. a new gna gene has been transferred into common spring wheat zhong60634 and winter wheat yumai66 with high yield by using the biolistic transformation method. transgenic wheat plants have been obtained in both of the two varieties. two transgenic plants (t0) have been obtained from the bombarded 535 immature embryos of zhong60634. bioassay results show that the development of aphid could ... | 2004 | 15473311 |
| ostrinia nubilalis parasitism and the field abundance of non-target insects in transgenic bacillus thuringiensis corn (zea mays). | in this study, we evaluated in field trials the effects on non-target species, of transgenic corn producing the cry1ab toxin of bacillus thuringiensis (bt). in 1998, we collected ostrinia nubilalis (hübner) larvae from transgenic bt corn (novartis hybrid 176) and non-bt corn at four geographical sites. we found a significant variation in parasitism by the tachinids lydella thompsoni (herting) and pseudoperichaeta nigrolineata (walker) among sites, and more parasitism in non-bt than in bt fields. ... | 2002 | 15612256 |
| effect of host defense chemicals on clonal distribution and performance of different genotypes of the cereal aphid sitobion avenae. | five microsatellite loci were used to study the genetic variability and population structure of sitobion avenae (hemiptera: aphididae) on some of its host plants. individuals were collected in chile from different cultivated and wild poaceae. forty-four multilocus genotypes were found among the 1052 aphids analyzed, of which four represented nearly 90% of the sample. no specialist genotypes were found, although some preferred hosts endowed with chemical defenses, i.e., hydroxamic acids (hx), whi ... | 2004 | 15724968 |
| estimation of hymenopteran parasitism in cereal aphids by using molecular markers. | polymerase chain reaction (pcr) primers were designed and tested for identification of immature parasitoids in small grain cereal aphids and for estimation of parasitism rates. pcr technique was evaluated for 1) greenhouse-reared greenbugs, schizaphis graminum (rondani), parasitized by lysiphlebus testaceipes cresson and 2) aphids collected from winter wheat fields in caddo county, oklahoma. for greenhouse samples, parasitism frequencies for greenbugs examined by pcr at 0, 24, and 48 h after rem ... | 2005 | 15765686 |
| genetic structure and clonal diversity of an introduced pest in chile, the cereal aphid sitobion avenae. | in chile, the aphid sitobion avenae is of recent introduction, lives on cultivated and wild poaceae, and is thought to reproduce by permanent parthenogenesis. in order to study the genetic variability and population structure of this species, five microsatellite loci were typed from individual aphids collected from different cultivated and wild host plants, from different geographical zones, and years. chilean populations showed a high degree of heterozygosity and a low genetic variability acros ... | 2005 | 15931255 |
| low temperature acclimated populations of the grain aphid sitobion avenae retain ability to rapidly cold harden with enhanced fitness. | in contrast to previous studies of rapid cold-hardening (rch), which have investigated the responses of insects maintained under 'summer conditions' (20 degrees to 25 degrees c), this study focuses on the ability of low-temperature acclimated insects to undergo rch. when the grain aphid sitobion avenae fabricus was low-temperature acclimated by rearing for three generations at 10 degrees c, the discriminating temperatures (temperature that results in approximately 20% survival after direct trans ... | 2005 | 15961747 |
| limited genetic exchanges between populations of an insect pest living on uncultivated and related cultivated host plants. | habitats in agroecosystems are ephemeral, and are characterized by frequent disturbances forcing pest species to successively colonize various hosts belonging either to the cultivated or to the uncultivated part of the agricultural landscape. the role of wild habitats as reservoirs or refuges for the aphid sitobion avenae that colonize cultivated fields was assessed by investigating the genetic structure of populations collected on both cereal crops (wheat, barley and oat) and uncultivated hosts ... | 2005 | 16024367 |
| 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 |
| detection of secondary predation by pcr analyses of the gut contents of invertebrate generalist predators. | predation by generalist predators is difficult to study in the field because of the complex effects of positive and negative interactions within and between predator species and guilds. predation can be monitored by molecular means, through identification of prey dna within predators. however, polymerase chain reaction (pcr) amplification of prey dna from predators cannot discriminate between primary and secondary predation (hyperpredation), in which one predator feeds on another that has recent ... | 2005 | 16313606 |
| the role of large-scale spatially explicit and small-scale localized processes on the population dynamics of cereal aphids. | a field-scale study of the spatially explicit interaction between the carabid poecilus cupreus linnaeus, and two common aphid species (sitobion avenae (fabricius) and metopolophium dirhodum (walker)) in winter wheat was conducted. all three species showed considerable spatial pattern at the field scale. activity-density of p. cupreus was an order of magnitude higher in the central part of the field compared to its periphery. where p. cupreus activity-density was highest, s. avenae and m. dirhodu ... | 2005 | 16336705 |
| contrasting behaviour of cadmium and zinc in a soil-plant-arthropod system. | this study investigates the transfer of cd and zn from a soil amended with sewage sludge at rates up to 100 t ha(-1) through a multi-trophic system consisting of barley, the aphid sitobion avenae and the larvae of the lacewing chrysoperla carnae. results show marked differences in the transfer of the two metals. cadmium was freely accumulated in barley roots, but accumulation in the shoot was restricted to a concentration of around 0.22 mg kg(-1) (dry weight). this limited the transfer of cd to ... | 2006 | 16434077 |
| effect of 6-methoxybenzoxazolin-2-one (mboa) on the reproduction rate of the grain aphid (sitobion avenae f.). | partial host-plant resistance could make a substantial contribution to reducing the damage caused by economically important grain aphids and, therefore, to reduced insecticide use. naturally occurring hydroxamic acids, in particular 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (dimboa), have been shown to be involved in the resistance of cereals to insects. dimboa is unstable in aqueous solutions and has been reported to decompose to 6-methoxybenzoxazolin-2-one (mboa). mboa was tested on grain a ... | 2006 | 16478213 |
| influence of aphid species and barley yellow dwarf virus on soft red winter wheat yield. | yield loss in soft red winter wheat, triticum aestivum l., caused by aphid-transmitted barley yellow dwarf virus (family luteoviridae, genus luteovirus, bydv) was measured over a 2-yr period in central missouri. rhopalosiphum padi (l.) was the most common and economically important species, accounting for > 90% of the total aphids. schizaphis graminum (rondani), rhopalosiphum maidis (fitch), and sitobion avenae (f.) made up the remainder of the aphids. aphid numbers peaked at wheat stem elongati ... | 2005 | 16539127 |
| cloning and sequence analysis of 2 different acetylcholinesterase genes in rhopalosiphum padi and sitobion avenae. | two genes encoding different acetylcholinesterases (ache) were successfully cloned from 2 species of aphid, rhopalosiphum padi (l.) and sitobion avenae (f.). they were named rp.ache1 (genbank accession no. ay707318), rp.ache2 (ay667435), sa.ache1 (ay707319), and sa.ache2 (ay819704), and were 2133, 2363, 2131, and 2362 bp in length and encoded 664, 676, 664, and 676 amino acids, respectively. all of them shared the characteristics of the ache family: catalytic tiads, 3 intra-chain disulfide bridg ... | 2006 | 16604106 |
| silica in grasses as a defence against insect herbivores: contrasting effects on folivores and a phloem feeder. | 1. silica, deposited as opaline phytoliths in the leaves of grasses, constitutes 2-5% of dry leaf mass, yet its function remains unclear. it has been proposed that silica may act as an antiherbivore defence by increasing the abrasiveness and reducing the digestibility of grass leaves, although there is little direct experimental evidence to support this. 2. we investigated the effects of manipulated silica levels on the abrasiveness of the leaves of five grass species. we also examined the effec ... | 2006 | 16638012 |
| [responses of spring wheat to elevated co2 and their effects on sitobion avenae aphid growth, development and reproduction]. | the study on the responses of spring wheat (triticum aestivum) potted in open-top chamber to elevated co2 (542.1 +/- 24.8 and 738.8.0 +/- 25.7 microl x l(-1) vs. 382.4 +/- 24.8 microl x l(-1)) and their effects on sitobion avenae aphid growth, development and reproduction showed that elevated co2 was advantageous for spring wheat growth. in treatments 550 and 750 microl co2 x l(-1), the plant height during may 5 approximately june 14 increased by 2.80% approximately 14.92% and 6.30% approximatel ... | 2006 | 16689241 |
| [effects of spring wheat varieties on growth, development and fecundity of sitobion avenae (f.) (homoptera: aphididae)]. | effects of seven varieties of spring wheat on the population parameters of sitobion avenae (f.) were investigated at 25 degrees c in the laboratory. the results indicated that there were significant differences in the developmental duration, mortality of nymph aphids, the longevity and fecundity of adults. the adults had shorter longevity and poorer fecundity when reared with the leaves of higher resistant w heat varieties. the level of wheat resistance was in order of liaochun 10 >02c-mb >xinch ... | 2006 | 16706070 |
| sources of variation in the interaction between three cereal aphids (hemiptera: aphididae) and wheat (poaceae). | the relative contributions of host plant, herbivore species and clone to variation in the interaction between cereal aphids and wheat were investigated using five clones each of three species, rhopalosiphum padi (linnaeus), sitobion avenae (fabricius) and schizaphis graminum (rondani), on seedlings of two cultivars of triticum aestivum l. and one cultivar of triticum durum desf. more individuals and biomass of r. padi than of the other two species were produced on seedlings. the three wheat cult ... | 2006 | 16768811 |
| comparing growth patterns among field populations of cereal aphids reveals factors limiting their maximum abundance. | cereal stands in central europe are commonly infested with three species of aphids that may become serious pests. with increasing abundance, the proportion of a particular species in the total aphid population may remain constant, suggesting a density-independent exponential growth, or the proportion can change, suggesting density-dependent constraints on growth. the constraints that affect particular species, and thus their relative abundance, were studied. the proportionality between maximum a ... | 2006 | 16768815 |
| tracing individual movements of aphids reveals preferential routes of population transfers in agroecosystems. | agricultural pests are not restricted to crops, but often simultaneously or successively use different cultivated and uncultivated hosts. nevertheless, the source-sink role of cultivated and uncultivated habitats in the life cycle of crop pests remains poorly understood. this is largely due to the difficulty of tracking displacements of small organisms in agricultural landscapes. we used stable-isotope ratios in order to infer the natal host plant of individuals of the english grain aphid sitobi ... | 2006 | 16826984 |
| species marker for developing novel and safe pesticides. | current anticholinesterase pesticides developed during world war ii are toxic to mammals because they target a catalytic serine residue of acetylcholinesterases (aches) in insects and in mammals. a sequence analysis of aches from 68 species and three-dimensional models of the greenbug and english grain aphid aches reported herein reveal that a cysteine residue is present at the active sites of greenbug and aphid aches but absent at those of mammalian aches. this discovery enables the design of n ... | 2007 | 17046256 |
| novel acetylcholinesterase target site for malaria mosquito control. | current anticholinesterase pesticides were developed during world war ii and are toxic to mammals because they target a catalytic serine residue of acetylcholinesterases (aches) in insects and in mammals. a sequence analysis of aches from 73 species and a three-dimensional model of a malaria-carrying mosquito (anopheles gambiae) ache (agache) reported here show that c286 and r339 of agache are conserved at the opening of the active site of aches in 17 invertebrate and four insect species, respec ... | 2006 | 17183688 |
| parasitism of greenbug, schizaphis graminum, by the parasitoid lysiphlebus testaceipes at winter temperatures. | functional responses by lysiphlebus testaceipes (cresson), a common parasitoid of small grain aphids, on greenbug, schizaphis graminum (rondani), were measured at seven temperatures (14, 12, 10, 8, 6, 4, and 2 degrees c) during a 24-h period (12-h light: 12-h dark). oviposition by l. testaceipes ceased at temperatures <4 degrees c. at all experimental temperatures, a type i, rather than a type ii or type iii, functional response was determined to be the best fit based on coefficient of determina ... | 2007 | 17349109 |
| mutations in acetylcholinesterase genes of rhopalosiphum padi resistant to organophosphate and carbamate insecticides. | apple grain aphid, rhopalosiphum padi (linnaeus), is an important wheat pest. in china, it has been reported that r. padi has developed high resistance to carbamate and organophosphate insecticides. previous work cloned from this aphid 2 different genes encoding acetylcholinesterase (ache), which is the target enzyme for carbamate and organophosphate insecticides, and its insensitive alteration has been proven to be an important mechanism for insecticide resistance in other insects. in this stud ... | 2007 | 17546082 |
| [effects of wheat leaf surface waxes on the feeding of two wheat aphid species]. | by using gc-ms and bioassay techniques, this paper studied the effects of different wheat varieties (cultivars) leaf surface waxes on the feeding of wheat aphids sitobion avenae and rhopalosiphum padi. the results showed that the leaf surface waxes of wheat varieties (cultivars) sn80, sn18 and zimail2 could stimulate the feeding of test aphids, while sn87 could not. gc-ms analysis showed that the chemical composition of leaf surface waxes differed with wheat varieties (cultivars). the main compo ... | 2007 | 17974245 |
| seasonal and annual genotypic variation and the effect of climate on population genetic structure of the cereal aphid sitobion avenae in northern france. | changes in the genetic structure and genotypic variation of the aphid sitobion avenae collected from cereal crops in northern france were examined by analysing variation at five microsatellite loci across several years and seasons. little regional and temporal differentiation was detected, as shown by very low fst among populations. repeated genotypes, significant heterozygote deficits, positive fis values and frequent linkage disequilibria were found in nearly all samples, suggesting an overall ... | 2008 | 18076784 |
| monoclonal antibodies reveal changes in predator efficiency with prey spatial pattern. | spatially explicit predator-prey interactions can alter the predatory potential of natural enemies augmented through conservation biological control. to test hypotheses regarding such interactions and predatory efficiency, we used a combination of molecular techniques and mark-release-recapture to study the foraging behaviour of a generalist carabid predator, poecilus cupreus, in response to spatial patterns of its cereal aphid prey (metapolophium dirhodum and sitobion avenae). beetle and aphid ... | 2008 | 18284569 |
| cursorial spiders retard initial aphid population growth at low densities in winter wheat. | generalist predators contribute to pest suppression in agroecosystems. spider communities, which form a substantial fraction of the generalist predator fauna in arable land, are characterized by two functional groups: web-building and cursorial (non-web-building) species. we investigated the relative impact of these two functional groups on a common pest (sitobion avenae, aphididae) in wheat by combining a molecular technique that revealed species-specific aphid consumption rates with a factoria ... | 2008 | 18439342 |
| the effects of temperature on detection of prey dna in two species of carabid beetle. | pcr-based techniques to investigate predator-prey trophic interactions are starting to be used more widely, but factors affecting dna decay in predator guts are still poorly understood. here, we investigated the effects of time since feeding, temperature and amplicon size on the detectability of prey dna in the gut content of two closely related predator species. cereal aphids, sitobion avenae, were fed to the carabid beetles pterostichus melanarius and nebria brevicollis. beetles were allowed t ... | 2008 | 18439345 |
| host specialization in habitat specialists and generalists. | generalists and specialists use different cues to find their habitat and essential resources. while generalists have the advantage of exploiting a wider range of resources, they are predicted to be less efficient in using one particular resource compared to specialists. the level of specialization of parasitoids can be either at the habitat or at the host level; strategies used by either type are expected to differ. we examined interactions between three aphid parasitoid species that are a habit ... | 2008 | 18443827 |
| role of accessory salivary glands in aphid transmission of barley yellow dwarf virus. | barley yellow dwarf virus (bydv) was consistently observed in the basal lamina and in plasmalemma invaginations only of accessory salivary glands in each of 20 aphids (sitobion avenae) reared on oats infected with the mav or rpv isolates of bydv. virus particles were not found in any of 13 aphids reared in parallel on healthy oats. the mav isolate was identified in aphids by indirect labeling with ferritin-conjugated antibody. virus particles were also observed within cytoplasmic vesicles and in ... | 1980 | 18631658 |
| vascular cell alterations and predisposed xylem infection in oats by inoculation with paired barley yellow dwarf viruses. | electron microscope studies of tissue doubly infected with sitobion avenae-specific and rhopalosiphum padi-specific variants of barley yellow dwarf virus revealed four types of alteration patterns in infected phloem cells not previously observed in tissue infected with either isolate alone. cells with alteration patterns similar to those in tissue singly infected with either variant were also present. double infections with isolates mav (s. avenae-specific) and rpv (r. padi-specific) predisposed ... | 1981 | 18635099 |
| aglomerular hemipteran antennal lobes--basic neuroanatomy of a small nose. | we have compared the basic organization of the primary olfactory centre, the antennal lobe (al), in 4 hemipteran species representing the 2 major lineages in this order. the homoptera were represented by the psyllid trioza apicalis and its aphid relatives the grain aphid sitobion avenae fabricius and the rose-grain aphid metopolophium dirhodum walker, whereas the heteroptera were represented by the pentatomid stink bug euschistus heros fabricius. the olfactory systems of psyllids and aphids are ... | 2008 | 18653643 |
| endoparasitism in cereal aphids: molecular analysis of a whole parasitoid community. | insect parasitoids play a major role in terrestrial food webs as they are highly diverse, exploit a wide range of niches and are capable of affecting host population dynamics. formidable difficulties are encountered when attempting to quantify host-parasitoid and parasitoid-parasitoid trophic links in diverse parasitoid communities. here we present a dna-based approach to effectively track trophic interactions within an aphid-parasitoid food web, targeting, for the first time, the whole communit ... | 2008 | 18662231 |
| [effects of wheat-oilseed rape or wheat-garlic intercropping on the population dynamics of sitobion avenae and its main natural enemies]. | sitobion avenae (fabricius) is one of the most important pests of winter wheat in china. an investigation was conducted at the experimental farm of shandong agricultural university to study the effects of intercropping oilseed rape or garlic with winter wheat on the population dynamics of s. avenae and its main natural enemies. the results showed that in most cases, the population density of s. avenae apterae was significantly lower in wheat-oilseed rape and wheat-garlic intercropping fields tha ... | 2008 | 18808028 |
| plum pox in north america: identification of aphid vectors and a potential role for fruit in virus spread. | abstract thirteen aphid species were tested for their ability to transmit pennsylvania isolates of plum pox virus (ppv) collected in columbia (penn-3), franklin (penn-4), and york (penn-7) counties, pa. four species, aphis fabae, a. spiraecola, brachycaudus persicae, and myzus persicae, consistently transmitted ppv in preliminary transmission tests. two species, metopolophium dirhodum and rhopalosiphum padi, were occasional inefficient vectors. toxoptera citricida, from florida, also was an effe ... | 2004 | 18943108 |
| transmission efficiency of cucumber mosaic virus by aphids associated with virus epidemics in snap bean. | cucumber mosaic virus (cmv) is a major component of the virus complex that has become more pronounced in snap bean in the midwestern and northeastern united states since 2001. multiple-vector-transfer tests were done to estimate the cmv transmission efficiencies (p) of the main aphid species identified in commercial snap bean fields in new york and pennsylvania. the four most efficient vectors (p > 0.05) were aphis gossypii, a. glycines, acyrthosiphon pisum, and therioaphis trifolii, which were ... | 2008 | 18943413 |
| analyzing and modeling temporal disease progress of barley yellow dwarf virus serotypes in barley fields. | abstract population dynamics of padi avenae (pav), macrosiphum avenae (mav), and rhopalosiphum padi (rpv) virus serotypes of barley yellow dwarf virus (bydv) and of their main aphid vectors were studied in winter barley (hordeum vulgare) fields for three successive years in western france. an epidemiological model of the spread of viruses in the field was developed based on vector populations as forcing variables and the population dynamics of each virus serotype. this model accurately simulated ... | 2000 | 18944507 |
| how could host discrimination abilities influence the structure of a parasitoid community? | three related aphidius parasitoid species share the same host, the grain aphid sitobion avenae. among this parasitoid community, aphidius rhopalosiphi is the most abundant species in the field. both the interspecific host discrimination of a. rhopalosiphi towards hosts parasitized by the two other species (i.e. a. avenae and a. ervi) and the interspecific host discrimination of the two other species towards hosts parasitized by a. rhopalosiphi were studied here. results showed that females of a. ... | 2009 | 19063755 |
| constitutive and induced activities of defense-related enzymes in aphid-resistant and aphid-susceptible cultivars of wheat. | phenylalanine ammonia-lyase (pal), polyphenol oxidase (ppo), and peroxidase (pod) are considered important biochemical markers in host plant resistance against pest insects. constitutive activity of these enzymes was analyzed in resistant and susceptible wheat cultivars against cereal aphid sitobion avenae (f.) at various developmental stages, i.e., tillering, stem elongation, flag leaf, and ear. following aphid infestation, the activity of these enzymes was determined at the flag leaf and ear s ... | 2009 | 19159980 |
| detoxification of gramine by the cereal aphid sitobion avenae. | secondary metabolites play an important role in host plant resistance to insects, and insects, in turn, may develop mechanisms to counter plant resistance mechanisms. in this study, we investigated the toxicity of gramine to the cereal aphid sitobion avenae and some enzymatic responses of s. avenae to this alkaloid. when s. avenae fed on an artificial diet containing gramine, mortality occurred in a dose-dependent manner. the lc(50) of gramine was determined to be 1.248 mm. in response to gramin ... | 2009 | 19224277 |
| energetic costs of detoxification systems in herbivores feeding on chemically defended host plants: a correlational study in the grain aphid, sitobion avenae. | herbivorous insects have developed mechanisms to cope with plant barriers, including enzymatic systems to detoxify plant allelochemicals. detoxification systems may be induced when insects are feeding on plants with increasing levels of allelochemicals. increases in enzymatic activity have been related to energetic costs, and therefore less energy may be allocated to fitness-related traits. in this study, we explored the induction and energetic costs of detoxifying hydroxamic acids (hx; a wheat ... | 2009 | 19329751 |
| multiple mechanisms responsible for differential susceptibilities of sitobion avenae (fabricius) and rhopalosiphum padi (linnaeus) to pirimicarb. | both sitobion avenae (fabricius) and rhopalosiphum padi (linnaeus) are the most important pests of wheat in china and usually coexist on the late period of wheat growth. pirimicarb was introduced into china for wheat aphid control in early 1990s, and differential susceptibilities of sitobion avenae (fabricius) and rhopalosiphum padi (linnaeus) to pirimicarb have been observed. a bioassay exhibited that rhopalosiphum padi possessed significantly higher susceptibility to pirimicarb than sitobion a ... | 2009 | 19413913 |
| [effects of uv-radiation on biological characteristics of different body-color biotypes of sitobion avenae (fab.)]. | uv-radiation exerts strong selection stress on the evolution of aphid populations, and thus, leads to their genetic differentiation. however, the effects of uv-radiation on different body-color biotypes of aphids are still ambiguous. in this study, new-born nymphae of red and green biotypes of sitobion avenae were placed on two wheat varieties (xiaoyan-22 and astron), bred in an artificial bioclimatic chamber under strict controlled conditions (at 15 degrees c, 20 degrees c, and 25 degrees c, an ... | 2009 | 19565787 |
| aphid fecundity and grassland invasion: invader life history is the key. | loss or gain of pathogens can determine the trajectory of biological invasions, and invasion by novel hosts also can alter pathogen dynamics to facilitate invasion. recent empirical and theoretical work has implicated infection by barley and cereal yellow dwarf viruses (b/cydv), a group of generalist pathogens of the poaceae family (grasses), as a necessary precursor to the invasion of over 9 million hectares of california's perennial grasslands by exotic annual grasses. the mechanism underlying ... | 2009 | 19688926 |
| diuraphis noxia reproduction and development with a comparison of intrinsic rates of increase to other important small grain aphids: a meta-analysis. | the russian wheat aphid, diuraphis noxia (kurdjumov), is a significant pest of small grains in the united states and worldwide. there is an increasing need for quality population dynamic models to aid in development of integrated pest management strategies. unfortunately, there exists high variability in published data regarding basic life history traits that frequently direct model parameterization. metadata were analyzed to develop relationships between temperature and reproductive and develop ... | 2009 | 19689884 |
| biochemical markers of oxidative stress within tissues of cereal aphids. | effects of some dietary o-dihydroxyphenols on biochemical markers of oxidative stress within tissues of sitobion avenae (fabricius), (homoptera, aphididae) and rhopalosiphum padi (linnaeus), (homoptera, aphididae) has been studied. among the studied aphid morphs the highest concentration of total thiols, hydrogen peroxide and lipid peroxidation products (tbars) was noted for winged adults (alatae). higher content of h2o2 was observed within tissues of the oligophagous species r. padi while the m ... | 2009 | 19700385 |
| elevated co2 changes interspecific competition among three species of wheat aphids: sitobion avenae, rhopalosiphum padi, and schizaphis graminum. | effects of elevated co2 (twice ambient) on the interspecific competition among three species of wheat aphids (sitobion avenae, rhopalosiphum padi, and schizaphis graminum) and on wheat-aphid interactions were studied. wheat plants had higher biomass and yield and lower water and nitrogen content of grain when grown under elevated co2 than under ambient co2; levels of condensed tannins, total phenols, and total nonstructural carbohydrates were also higher in wheat ears under elevated co2. compare ... | 2009 | 19791595 |
| altruistic defence behaviours in aphids. | altruistic anti-predatory behaviours pose an evolutionary problem because they are costly to the actor and beneficial to the recipients. altruistic behaviours can evolve through indirect fitness benefits when directed toward kin. the altruistic nature of anti-predatory behaviours is often difficult to establish because the actor can obtain direct fitness benefits, or the behaviour could result from selfish coercion by others, especially in eusocial animals. non-eusocial parthenogenetically repro ... | 2010 | 20089189 |
| activation of defense mechanism in wheat by polyphenol oxidase from aphid saliva. | the saliva of two cereal aphids, sitobion avenae and schizaphis graminum in third-instar nymphs, was collected after 24 h of feeding by 30 aphids, separately, on artificial diet sachets, and the salivary enzymes were determined. the result showed that polyphenol oxidase (ppo) existed in the saliva of both aphid species, and the enzymatic activities were 6.2 x 10(-3) u/g for s. avenae and 2.37 x 10(-1) u/g for s. graminum, revealing a 38-fold higher activity in the saliva of s. graminum than in t ... | 2010 | 20112908 |
| insecticidal activity of recombinant avidin produced in yeast. | an expression construct encoding chicken (gallus gallus) avidin was assembled from amplified fragments of genomic dna. recombinant, functional avidin was produced in pichia pastoris, with yields of up to 80 mg/l of culture supernatant. the recombinant avidin had similar insecticidal activity to egg white avidin when assayed against larvae of a lepidopteran crop pest, cabbage moth (mamestra brassicae), causing >90% reduction in growth and 100% mortality when fed in optimised diets at levels of 1. ... | 2010 | 20132821 |
| physiological approach to explain the ecological success of 'superclones' in aphids: interplay between detoxification enzymes, metabolism and fitness. | 'superclones' are predominant and time-persistent genotypes, exhibiting constant fitness across different environments. however, causes of this ecological success are still unknown. therefore, we studied the physiological mechanisms that could explain this success, evaluating the effects of wheat chemical defences on detoxification enzymes [cytochrome p450 monooxygenases (p450), glutathione s-transferases (gst), esterases (est)], standard metabolic rate (smr), and fitness-related traits [adult b ... | 2010 | 20223246 |
| cloning and phylogenetic analysis of sid-1-like genes from aphids. | abstract the sid-1 (systemic interference defective) gene encodes a transmembrane protein that is an important participator in the systemic rnai pathway and has been reported in several organisms. in insects, sid-1-like genes were described from tribolium castaneum, apis mellifera, bombyx mori and schistocerca americana, but were not found in drosophila melanogaster and anopheles gambiae. to investigate whether this gene occurs in aphid species, rt-pcrs were performed using degenerate primers de ... | 2008 | 20302524 |
| investigation of structure-activity relationships in organophosphates-cholinesterase interaction using docking analysis. | it is known than the most potent homologues in various series of o,o-dialkylphosphates are the dibutyl or diamyl derivatives toward mammalian cholinesterases (ches) (both acetyl- and butyryl-ches), and the dimethyl or diethyl ones toward insect aches. to investigate the che interaction with organophosphorus inhibitors (opis) in more detail, we have performed in silico docking of the series of o,o-dialkylfluorophosphates into active center of different ches - both from mammals (human and mouse ac ... | 2010 | 20347727 |