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Highlights • We tested the attractiveness of volatiles from aphid × plant combinations to H. axyridis adults. • H. axyridis preferred aphid-infested plants over un-infested plants or aphids alone. • Five kinds of volatiles preferred by H. axyridis were identified. Abstract Volatiles play important roles in the recruitment of arthropod natural enemies, and are widely used in foraging by the multicolored Asian lady beetle Harmonia axyridis Pallas (Coleoptera: Coccinellidae). In its native range in Asia and throughout its invaded range, H. axyridis preys upon multiple species of aphids in both natural and agricultural settings, yet little is known about the volatile cues it employs to locate prey items. In this study, we test the attractiveness of volatiles emanating from four different aphid × plant combinations to H. axyridis adults in a Y-tube olfactometer. More specifically, we exposed host plants from various plant families as such: Artemisia lavandulaefolia (Asteraceae) with Macrosiphoniella artemisiae ; Gossypium hirsutum (Malvaceae) with Aphis gossypii ; Triticum aestivum (Poaceae) with Sitobion avenae and Schizaphis graminum ; and Vicia faba (Fabaceae) with Megoura viciae. Next, using coupled gas chromatography – electroantennogram detection (GC-EAD) and gas chromatography – mass spectrometry (GC-MS), we identified the volatile compounds from aphid × plant combinations that elicit electrophysiological activity in H. axyridis adults. Lastly, a total of five volatiles were assessed in open-field tests with barrel traps. In olfactometer assays, H. axyridis adults preferred aphid-infested plants over un-infested plants or aphids alone. In GC-EAD trials, seven electrophysiologically-active compounds were found; and in ensuing behavioral assays, ladybeetles preferred five kinds of volatiles (i.e., p-diethylbenzene, 3-ethylacetophenone, 1,2-diethylbenzene, α-pinene and butyl acrylate). In open-field tests, H. axyridis were significantly attracted to all five info-chemicals at a concentration 100 mg/ml. Our work not only sheds light upon H. axyridis chemical ecology, but equally provides important information that can facilitate the future development of integrated pest management (IPM) tactics for aphid control or volatile-based trapping and monitoring technologies for H. axyridis in its invaded range. [ABSTRACT FROM AUTHOR]

Summary: Phloem sap quality can differ between and within plants, and affect the performance of aphids. In turn, aphid infestation may change the chemical composition and nutritional value of phloem sap. However, the effects of different aphid species on the overall phloem sap composition of distinct parts within plant individuals in relation to aphid performance remain unclear.To test the specificity of plant responses to aphids, we used two chemotypes of Tanacetum vulgare plants and placed the monophagous aphids Macrosiphoniella tanacetaria and Uroleucon tanaceti on different plant parts (stems close to the inflorescence, young and old leaves). Aphid population growth was determined and sugars, organic acids, amino acids and metabolic fingerprints of phloem exudates were analysed.Macrosiphoniella tanacetaria performed best on stems, whereas U. tanaceti performed best on old leaves, indicating differences in niche conformance. Aphid infestation led to distinct changes in the phloem exudate composition of distinct metabolite classes, differing particularly between plant parts but less between chemotypes.In summary, plant responses to aphids are highly specific for the chemotype, plant part, metabolite class and aphid species. These changes may indicate that aphids construct their own niche, optimizing the food quality on the plant parts they prefer. [ABSTRACT FROM AUTHOR]

Nowadays, food security is a vital issue and antimicrobial packaging could play an important role in this matter. In this regard, Salvia macrosiphon seed mucilage (SSM) and nanoclay, as new sources for the production of food-grade edible films were investigated. These edible films were prepared by incorporation of SSM with glycerol and different percentage of nanoclay. Upon addition of nanoclay up to 2% physical, mechanical and thermal properties were considerably improved and the composite films showed the lowest water vapor permeability (WVP), as well as highest elongation at break and tensile strength. The nanocomposite edible films also showed antibacterial activity due to the SSM nature. Addition of nanoclay, increased the hydrophobicity, which makes the films great alternatives for food packaging. This study revealed that these novel antimicrobial edible films could be a promising packaging option for a wide range of food products. [ABSTRACT FROM AUTHOR]

Plant chemistry is one of the main drivers of herbivore distribution. Monophagous herbivore species are highly specialized, but even within their only host species the chemistry varies. The herbivore's choice is initially mainly guided by volatile plant compounds. Once on the plant, particularly for aphids the phloem quality affects their performance. However, little is known about the intraspecific and intra-individual variation in phloem sap and their influences on monophagous aphids. To determine potential mechanisms involved in aphid colonization, we tested the effects of intraspecific chemical variation in Tanacetum vulgare, which produces different chemotypes, on the preference of two monophagous aphid species. Moreover, we measured the performance of the aphids on different plant parts (stem close to the inflorescence, young and old leaves) of these chemotypes and analyzed their phloem sap composition. Both species preferred the β-thujone (THU) over the trans-carvyl acetate (CAR) chemotype in dual-choice assays. Survival of Macrosiphoniella tanacetaria was neither affected by intraspecific nor intra-individual variation, whereas the reproduction was highest on stems. In contrast, Uroleucon tanaceti survived and reproduced best on old leaves of the preferred chemotype. The sugar, organic acid and amino acid composition pronouncedly differed between phloem exudates of different plant parts, but less between chemotypes. Unexpectedly, high concentrations of amino acids did not necessarily enhance aphid performance. These different performance optima may cause niche differentiation and, therefore, enable co-existence. In conclusion, the tremendous variation in plant chemistry even within one species can affect the distribution of highly specialized aphids at various scales aphid species-specifically. [ABSTRACT FROM AUTHOR]

Aphidoidea, endosymbiotic bacteria, bacteriocytes, transovarial transmission of endosymbiotic bacteria The ultrastructure, distribution and transovarial transmission of endosymbiotic bacteria in representatives of six aphid families: Eriosomatidae (Pemphigus spyrothecae, Prociphilus fraxini), Anoeciidae [Anoecia (Anoecia) corni], Drepanosiphidae [Mindarus abietinus, Sipha (Rungsia) maydis, Clethrobius comes, Myzocallis (Lineomyzocallis) walshii], Thelaxidae (Thelaxes dryophila), Aphididae (Delphiniobium junackianum, Aphis viburni, Cavariella theobaldi, Macrosiphoniella tanacetaria) and Lachnidae (Schizolachnus pineti, Eulachnus rileyi) were studied at the ultrastructural level. The ovaries of aphids are accompanied by large organs termed bacteriomes that consist of giant cells termed bacteriocytes. The bacteriocyte cytoplasm is tightly packed with endosymbiotic bacteria. Ultrastructural observations have shown that the bacteria Buchnera aphidicola (primary symbiont of aphids) present in various species are characterized by significant differences in both size and organization of their cytoplasm. In the aphids, Prociphilus fraxini, Sipha (Rungsia) maydis, Thelaxes dryophila, Aphis viburni, Cavariella theobaldi, Macrosiphoniella tanacetaria, Eulachnus rileyi and Schizolachnus pineti, in addition to Buchnera aphidicola, secondary endosymbionts are also present. The bacteriocytes containing secondary endosymbionts are less numerous than those with Buchnera. In Eulachnus rileyi (Lachnidae), in addition to primary and secondary endosymbionts, there is a third type of microorganism. In all species examined both the primary and secondary endosymbionts are transovarially transmitted from mother to offspring.

Aphids have developed symbiotic associations with different bacterial species, and some morphological and molecular analyses have provided evidence of the host relationship between the primary symbiotic bacteria (Buchnera aphidicola) and the aphid while the contrary with the secondary symbiotic bacteria. In this study, we investigated the phylogenetic relationships of the bacterial endosymbionts in the aphid Sitobion avenae (F.). We characterized all bacterial endosymbionts in 10 genetically defined S. avenae clones by denaturing gradient gel electrophoresis and, from these clones, sequenced the 16S rRNA genes of both the primary endosymbiont, B. aphidicola (for the first time), and the secondary endosymbionts, Regiella insecticola and Hamiltonella defensa (for the first time). The phylogenetic analysis indicated that Buchnera from Sitobion related to those in Macrosiphoni. The analysis of the secondary endosymbionts indicated that there is no host relationship between H. defensa and R. insecticola from Sitobion and those fromother aphid species. In this study, therefore, we identified further evidence for the relationship between Buchnera and its host and reported a relationship within the secondary endosymbionts of S. avenae from the same country, even though there were no relationships between the secondary bacteria and their host.We also discussed the diversity within the symbiotic bacteria in S. avenae clones [ABSTRACT FROM AUTHOR]

Aphids have caused great damage to chrysanthemum production, and it's crucial to breed new chrysanthemums with strong aphid resistance. However, little information is available regarding the inheritance of aphid resistance in chrysanthemum. The inheritance pattern of chrysanthemum aphid resistance within an F 1 segregating population was dissected with the major gene plus polygene mixed inheritance model and molecular markers. The result showed that aphid resistance of chrysanthemum is a quantitative trait with a moderate coefficient of variation >50%. The mixed inheritance model based on a single segregating generation suggested the inheritance of aphid resistance was controlled by two pairs of major genes with additive effect 0.68 and 0.39, respectively. The heritability of major gene was calculated at 89.21%. Marker-trait analysis based on one-way variance analysis uncovered 11 markers significantly associated with phenotype, cumulatively explaining ∼74% variation. Bulked segregant analysis (BSA) based on the gene bulks of high resistant and susceptive genotypes in F 1 population identified two SSR markers, SSR145-93 and SSR197-205, linked to high aphid resistance ( r > 0.4). The QTL analysis detected 5 putative QTL for aphid resistance in two successive years, with individual QTL explaining the phenotypic variation of 14.30–28.00%. The inheritance model and molecular markers identified for aphid resistance facilitate the ongoing breeding activities in chrysanthemum. [ABSTRACT FROM AUTHOR]

Abstract: Some predators have a broad prey range, but not all prey are equally suitable for a predator. We tested the suitability of three specialized tansy (Tanacetum vulgare) aphids, Macrosiphoniella tanacetaria, Metopeurum fuscoviride and Uroleucon tanaceti, on biological parameters of their major predators, Coccinella septempunctata and Chrysoperla carnea, when aphid species were offered either alone, or as a mixed diet of all the three aphid species. For the lacewing C. carnea, a diet consisting only of the generally ant-tended M. fuscoviride resulted in the shortest larval and total developmental time, in highest larval survival and pupation success. For the ladybird C. septempunctata, a pure diet of the non-tended M. tanacetaria was most suitable, resulting in the shortest total developmental time, heaviest fresh and dry weight. Larvae of both predator species had low survival and none of them developed to pupal stage when offered only U. tanaceti that has a bright red colour, is not ant-tended and feeds on the underside of lower leaves. The mixed diet of all three aphid species was worse than the best single-aphid diet for both predators, for almost all fitness parameters. Thus, while diet mixing may allow predators to avoid the negative impact of unsuitable prey, diet mixing does not necessarily result in the highest fitness of predators. [Copyright &y& Elsevier]

Two tansy-feeding aphids, Macrosiphoniella tanacetaria (MA) and Metopeurum fuscoviride (ME), were studied at a small spatial scale in and around Jena (< 80 km2) using polymorphic microsatellite markers. Both species were found in approximately 60% of sites formerly known to harbour the aphids, although, generally when they did occur, they occurred singly (MA ∼50%; ME ∼60%) and rarely together on the same plant at the same time (approximately 10%) and then usually only in the early part of the growing season. This difference may be a result of quasi-apparent competition effects elicited by ants farming ME aphids, and preferentially actively eliminating or disturbing MA aphids. In terms of population genetics, both aphids showed extreme genetic heterogeneity within a metapopulation structure, with ME more than MA (i.e. higher FST values, approximately 0.4 versus 0.15, respectively), and limited levels of interpopulation gene flow. Subpopulations often deviated from Hardy-Weinberg equilibrium and showed linkage disequilibria, as expected in animals with extended parthenogenetic reproduction, and had positive FIS values for most large samples, suggesting inbreeding, and possibly philopatry, certainly in ME. Hierarchical analysis (allele range and number per locus, analysis of molecular variance and FST) strongly suggested that the plant rather than site governs the level of genetic variation. Bayesian clustering analysis revealed that both species had heterogeneous historical genetic patterning, with K (number of subgroups) in the range 3-7. Evidence is also provided from isolation-by-distance and private allele analyses indicating that, in MA, the presence of winged autumn males, absent in ME where males are wingless, influences comparative population genetic structuring, such that ME subpopulations are comparatively more inbred and genetically differentiated than MA subpopulations. Lastly, additional spatial arrangement (ALLELES-IN-SPACE) analysis showed that, in both species, certain subpopulations were genetically isolated from the remainder, probably as a result of geographical barriers, including intervening buildings and woods. As such, the biology of these tansy aphids living in semi-natural habitats is very different from many pest aphid species examined within agro-ecosystems and infesting ephemeral crops. This is because the former appear to be much more reluctant to fly and hence show contrastingly much higher levels of interpopulation divergence, even at small spatial scales as investigated in the present study. Indeed, the number of genotypic clusters found for tansy aphids using Bayesian approaches is similar to that globally for the major pest, the peach-potato aphid, Myzus persicae. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104, 838-865. [ABSTRACT FROM AUTHOR]

The parasitoids (Hymenoptera: Braconidae: Aphidiinae) of Macrosiphoniella del Guercio (Hemiptera: Aphididae) from the western Palaearctic region are reviewed and keyed. The host associations and distribution of each species are summarized. Aphidius stigmaticus sp. nov. reared from Macrosiphoniella tanacetaria on Tanacetum polycephalum, which is another member of the Macrosiphoniella aphid parasitoid guild from high-mountain habitats in western Iran, is described in the present contribution. Some taxonomic problems within Macrosiphoniella parasitoid guilds are discussed as well. [ABSTRACT FROM AUTHOR]

Abstract: The steady shear flow properties of dispersions of a new potential hydrocolloid, sage seed gum (SSG), were determined as a function of concentration (0.5–2% w/w), and temperature (20–50°C). SSG dispersions exhibited strong shear-thinning behavior at all conditions tested, which was even more pronounced than commercial hydrocolloids like xanthan, guar gum and locust bean gum. Different time-independent rheological models were used to fit the experimental data, although the Herschel–Bulkley model (H–B) was found the best model to describe steady shear flow behavior of SSG. An increase in gum concentration led to a large increase in yield stress and consistency coefficient values, whereas there was no definite trend with an increase in temperature. On the other hand, the above-mentioned increases in concentration and temperature did not yield a clear evolution of the shear-thinning characteristics of SSG dispersions. An Arrhenius-type model was also used to describe the effect of temperature. The activation energy (E a) appeared in the range of 3949–16384J/mol, as concentration increased from 0.5 to 2%, at a shear rate of 100s−1. The yield stress values estimated by viscoplastic rheological models were much higher than the data determined by stress ramp method. Apparent viscosity of SSG surpassed many commercial hydrocolloids such as guar gum, locust bean gum, Tara gum, fenugreek gum and konjac gum at the same conditions, which suggest it as a very good stabilizer in food formulations. [ABSTRACT FROM AUTHOR]

In cyclical parthenogens, clonal diversity is expected to decrease due to selection and drift during the asexual phase per number of asexual generations. The decrease in diversity may be counteracted by immigration of new genotypes. We analysed temporal variation in clonal diversity in colonies of the monophagous tansy aphid, Macrosiphoniella tanacetaria (Kaltenbach), sampled four times over the course of a growing season. In a related field study, we recorded aphid colony sizes and the occurrence of winged dispersers throughout the season. The number of colonies increased from April, when asexual stem mothers hatched from the sexually produced eggs, to the end of June. The proportion of colonies with winged individuals also increased over this period. After a severe reduction in colony sizes in late summer, a second expansion phase occurred in October when sexuals were produced. At the season's end, the only winged forms were males. A linked genetic study showed that the number of microsatellite multilocus genotypes and genetic variability assessed at three polymorphic loci per colony decreased from June to October. Overall, the relatedness of wingless to winged individuals within colonies was lower than average relatedness among wingless individuals, suggesting that winged forms mainly originated in different colonies. The results demonstrate that patterns of genetic diversity within colonies can be explained by the antagonistic forces of clonal selection, migration and genetic drift (largely due to midsummer population bottlenecks). We further suggest that the males emigrate over comparatively longer distances than winged asexual females. [ABSTRACT FROM AUTHOR]