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The effects of two polyphenolic flavonoids (flavanone naringenin and flavonol quercetin) on development, fecundity, and mortality of the pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae), were determined in vitro, on an artificial diets. Also determined in vitro (DC EPG method), on sucrose-agarose gels, were the effects of flavonoids on the probing and feeding behavior of adult apterae. When added to a liquid diet, higher concentrations of studied flavonoids increased the developmental time, the pre-reproductive period, and mortality and decreased fecundity and the intrinsic rate of natural increase of A. pisum. In most events associated with stylet activity (as indicated by EPG waveform g-C), differences in probing behavior did not statistically differ between the control gel and those with flavonoids; quercetin at 10, 100, and 1,000 µg cm prolonged the number of gel penetrations; and quercetin only at 10,000 μg cm prolonged the time the first g-C waveform was observed. Addition of flavonoids to the gels generally reduced passive ingestion from fluids of the gels (EPG waveform g-E2). At higher concentrations (>1,000 µg cm) the flavonoids completely stopped salivation (EPG waveform g-E1) and passive ingestion from fluids of the gels (EPG waveform g-E2). In events associated with active ingestion (EPG waveform g-G), however, differences in feeding behavior did not statistically differ between the control gel and those with flavonoids. The present findings demonstrate detrimental effects of the flavanone naringenin and flavonol on the behavior of the pea aphid. This can be employed in a biotechnological projects for plant breeding resistant to herbivores, including aphids. [ABSTRACT FROM AUTHOR]

Electrical penetration graphs (DC EPG) were used to monitor the feeding behavior of the pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae) exposed to the flavonoids luteolin and genistein in artificial diets. The EPG patterns generated by aphids feeding on plants were used to interpret the patterns generated on the artificial diets. Addition of flavonoids to the diets generally prolonged the period of stylet probing (as indicated by EPG pattern d-C), reduced salivation (as indicated by pattern d-E1) and passive ingestion (as indicated by pattern d-E2), and also delayed the onset of salivation and passive ingestion. At higher concentrations (≥100 μg cm for luteolin, ≥1,000 μg cm for genistein), the flavonoids completely stopped salivation and passive ingestion. In most events associated with active ingestion (EPG pattern d-G), however, differences in feeding behavior did not statistically differ between the control diet and those with flavonoids; luteolin, and genistein only at 10 μg cm prolonged the time until the first d-G pattern was observed. The current findings demonstrate detrimental effects of the isoflavone genistein and the flavone luteolin on the feeding behavior of the pea aphid, A. pisum. This can be employed to create plants which are resistant to aphids and other herbivores. [ABSTRACT FROM AUTHOR]

Flavonoids play an important role in interactions of plants with the environment. Liquid chromatography (HPLC) was used to determine the flavonoid profiles (especially luteolin, tricin, and chrysoeriol glycosides), their total concentrations, and changes in the amounts of eight flavones found in the aerial parts of alfalfa (Medicago sativa L.) (Fabaceae) Radius cv., uninfested and infested by the pea aphid (Acyrthosiphon pisum Harris) (Homoptera: Aphididae). It was shown that both control and infested green aerial parts of alfalfa plants had similar flavonoid profiles. The dominant flavonoid of alfalfa was compound 7-O-[2-O-feruloyl-ß-D-glucuronopyranosyl(1→2)-O-ß-D-glucuronopyranosyl]-4'-O-ß-D-glucuronopyranosideluteolin. Compound 7-O-{2'-O-feruloyl-[ß-D-glucuronopyranosyl(1→3)]-O-ß-D- glucuronopyranosyl(1→2)-O-ß-D-glucuronopyranosidetricin was present in the smallest amounts. The total concentration of flavones was rather high and ranged from 11.13 to 12.34 mg/g d.m., but there were no significant differences between uninfested and infested alfalfa plants. There was a correlation between the concentration of flavonoid glycosides in the alfalfa plants and pea aphid abundance. Pea aphid daily fecundity per female was affected by luteolin, tricin, and chrysoeriol glycosides and the level of chrysoeriol glycosides affected ingestion of xylem sap by the aphid. This finding may indicate that the studied flavonoid glycoside forms are biologically active in alfalfa -- A. pisum interactions. [ABSTRACT FROM AUTHOR]

The effect of some species of the Fabaceae family (the pea Pisum sativum L., broad bean Vicia faba L. and vetch V. sativa L.) on biochemical markers of oxidative stress within tissues of the pea aphid, Acyrthosiphon pisum Harris (Homoptera, Aphididae), has been studied. The highest concentration of superoxide anion radical (O2-), hydrogen peroxide (H2O2) and lipid peroxidation products thiobarbituric acid reactive substances (TBARS) was recorded for morphs that fed on the broad bean. The opposite tendency was observed for the level of total thiols, that were the highest for insects reared on the pea. Among the studied aphid morphs, the highest concentration of superoxide anion and hydrogen peroxide was noted for the wingless females whereas TBARS content was the highest within the winged migrant tissues. Different results were obtained for the total thiols, where apterae as well as migrants reared on the tested plants, had comparable content of these compounds. Our experiments indicate that oxidative stress may play an important role in interactions between the pea aphid and their host plants. [ABSTRACT FROM AUTHOR]

We studied the development and feeding behaviour of the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), on the Radius and Sapko alfalfa ( Medicago sativa L.) (Fabaceae) cultivars. Three saponins and flavones were identified in the alfalfa cultivars after thin layer chromatography separation. Cultivar Radius differed from Sapko in that it had a higher level of saponins, including zanhic acid tridesmoside and 3-GlcA,28-AraRhaXyl medicagenic acid glycoside. The flavones identified, including 7- O-β-D-glucuronopyranosyl-4′- O-[2′- O-E-feruloyl- O-β-D-glucuronopyranosyl(1→2)- O-β-D-glucuronopyranoside] apigenin, 7- O-{2- O-E-feruloyl-[β-D-glucuronopyranosyl(1→3)]- O-β-D-glucuronopyranosyl(1→2)- O-β-D-glucuronopyranoside} apigenin, and 4′- O-[2′- O-E-feruloyl- O-β-D-glucuronopyranosyl(1→2)- O-β-D-glucuronopyranoside] apigenin, occurred in tissues of both alfalfa cultivars. However, cv. Radius had very low mean flavonoid concentrations in comparison to cv. Sapko. Pea aphids that fed on cv. Radius plants showed a reduction in reproduction and survival. The aphid pre-reproductive period on cv. Radius was prolonged and the reproductive and post-reproductive periods on cv. Radius were reduced, compared to those on cv. Sapko. Cultivar Radius also negatively influenced aphid probing behaviour. This was especially the case during the initial period of the pathway phase. The results suggested that alfalfa cv. Radius, which had a higher level of saponins and a lower level of flavonoids, was less accepted by the pea aphid. [ABSTRACT FROM AUTHOR]