ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1573-8248
    Keywords: host discrimination ; correspondence analysis ; superparasitism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Des cemelles d'Epidinocarsis lopezi sont confrontées à des lots de cochenilles-hôtes non parasitées ou contenant une proportion variable d'individus parasités. Les séquences de ponte obtenues dans les différentes situations sont filmées et découpées en unités de comportement ou item. L'analyse de la succession de ces unités permet la construction de diagrammes de flux sur plans factoriels caractéristiques de chaque type de séquence. La comparaison de ces diagrammes met en évidence la capacité discriminatoire des femelles parasitoïdes car l'importance relative des item est modifiée par le taux d'hôtes parasités rencontrés; elle donne aussi des indications sur les motivations d'une femelle lors de l'exploitation d'une placette (patch). De plus, l'analyse découpe la séquence de ponte en item liés à la recherche de l'hôte, item liés à la ponte proprement dite et item intervenant après la piqûre. Ces trois séries d'unités comportementales sont associées aux axes factoriels qui illustrent donc les tendances fondamentales du comportement de ponte.
    Notes: Abstract Females ofEpidinocarsis lopezi (De Santis) are presented with groups of unparasitized hosts or groups containing different ratios of parasitized hosts (Phenacoccus manihoti). Oviposition behaviour sequences obtained in various situations are filmed and split into units of behaviour or patterns. The succession of patterns is analyzed and translated into flow charts on factorial maps characteristic of each type of sequence. Comparison of flow charts reveals host discrimination by female parasitoids since the relative importance of behaviour patterns is modified according to the level of parasitized hosts encountered; it also gives clues to the strategy adopted by the female parasitoid during the search of a patch. In addition, the analysis divides the oviposition sequence into three separate patterns, specific to host search, oviposition act and post-oviposition behaviour. This series of patterns is closely related to factorial axes which indicates the fundamental trends of oviposition behaviour.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1570-7458
    Keywords: Rhopalosiphum padi ; alate forms ; potential fecundity ; morphometrics ; discriminant analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Des techniques d'analyse multivariée ont été appliquées sur des données morphométriques et anatomiques obtenues pour les trois formes femelles ailées (émigrants, exules ailés et gynopares) de Rhopalosiphum padi (L.) dans le but de les différencier. Pour cela des paramètres de la fécondité potentielle (nombre d'ovarioles, nombre d'embryons) et des variables morphologiques (mensurations, nombre de rhinaries) ont été évalués pour chacun des morphes sur des individus de trois populations ou clones d'origines géographiques distinctes (Angleterre, Normandie, Bretagne). Les analyses factorielles discriminantes réalisées sur ces données nous ont permis de séparer avec un taux de succès compris entre 93% et 100% les individus selon leur morphe. A partir de celles-ci nous avons pu proposer des critères susceptibles de différencier ces trois formes ailées. Le rapport ARS/TARS2 (longueur de l'article apical du rostre/longueur du deuxième segment du tarse postérieur) semble très bien discriminer les émigrants des exules ailés et a été appliqué sur des ailés de R. padi capturés par deux pièges à succion français et un suisse. La séparation des gynopares des exules ailés est par contre moins simple. La représentativité de l'échantillon analysé a été discutée. Les possibilités d'application des méthodes d'identification des morphes de R. padi sur les ailés capturés aux pièges à succion ont été envisagées dans le cadre de la prévision des risques d'infection des céréales par le virus de la Jaunisse Nanisante de l'Orge (BYDV) et de l'amélioration des connaissances en Biologie des Populations aphidiennes.
    Notes: Abstract Multivariate analysis methods were used to distinguish between the three female alate morphs of Rhopalosiphum padi (L.) (emigrants, alate exules and gynoparae). Fourteen morphometric descriptors and seven anatomical parameters indicative of their potential fecundity were considered. Three populations or clones from distinct areas were also taken into account. The three alate morphs were separated with between 93% and 100% success. Some simplified criteria allowing distinction are described, and as an example one of them was applied to R. padi alatae caught in three suction traps. The reliability of the samples analysed is discussed. Practical use of identification techniques described may have implications for forecasting (e.g. Barley Yellow Dwarf Virus Disease), and for improving knowledge of aphid population biology.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1570-7458
    Keywords: Cereal aphids ; Rhopalosiphum padi ; Sitobion avenae ; rate of increase ; fecundity ; alate ; apterous ; clone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Cette étude a eu pour but d'évaluer l'importance de facteurs intrinsèques (clone et morphe) sur les paramètres du taux d'accroissement de Sitobion avenae (F.) et Rhopalosiphum padi (L.). Pour chaque espèce, trois clones originaires de régions océaniques françaises ont été comparés à 20 °C pour les morphes exules ailés et exules aptères. L'effet du clone est significatif sur l'âge reproducteur (durée comprise entre la naissance du puceron et le début de sa phase de reproduction) et sur le taux intrinsèque d'accroissement naturel. Il est plus faible que celui du morphe avec lequel il intéragit dans le cas de R. padi. Les différences interspécifiques relevées mettent en évidence les capacités d'accroissement supérieures de R. padi par rapport à celles de S. avenae, dans le cas des ailés comme dans celui des aptères. Enfin, différents modèles ont été appliqués aux données de reproduction journalière des pucerons. Le type et la qualité des ajustements varient essentiellement en fonction du morphe.
    Notes: Abstract This study aimed at evaluating the influence of intrinsic factors (clone, morph) on the parameters of the intrinsic rate of increase of Sitobion avenae (F.) and Rhopalosiphum padi (L.). For each species, apterous and alate exules of three clones originating from French oceanic regions were compared at 20 °C. The clonal factor had a significant effect on both time from birth until onset of reproduction (TBR) and intrinsic rate of increase (r). This effect was lower than that of the morph. Moreover, in the case of R. padi, a strong clone-morph interaction was observed. Both apterous and alate morphs were shown to have a higher rate of increase in R. padi than in S. avenae. Various models were fitted to aphid daily rate of reproduction. Both types of model and quality of fit depended mainly on the morph.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1570-7458
    Keywords: Homoptera ; Sitobion avenae ; Triticum monococcum ; resistance mechanisms ; probing behaviour ; electronic monitoring ; flow charts ; correspondence analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The behaviour ofSitobion avenae (F.), was compared on resistant wheat lines ofTriticum monococcum (L.) and a susceptible variety ofTriticum aestivum (L.). Firstly, stylet penetration activities were monitored with the Electrical Penetration Graph (EPG) technique and subsequently analysed using flow charts combined with correspondence analysis. Plant resistance was shown to be associated with repeated penetrations without access to either the xylem or the phloem, and with numerous failures in starting a sustained sap ingestion (as represented by pattern E2). Access to sieve elements of the phloem did not seem to be much affected on resistant plants but it took the aphid three times as long to produce a sap ingestion pattern when maintained on the resistant lineT. monococcum no 44 (Tm44) as compared with aphids maintained on susceptible plants. As a result the total time spent in ingesting from sieve elements was reduced by 72% on Tm44. Secondly, direct observations of freely-moving apterous adults were performed. Aphids did not discriminate between resistant and susceptible wheat during the first 30 min of access to test leaves, but only 4 out of 25 aphids were still probing after eight hours on resistant Tm44. The relevance of these results to possible location of the resistance factor(s) are discussed. Although detection of plant resistance before sieve elements are reached can not be rigorously excluded, the factors involved inT. monococcum resistance toS. avenae undoubtedly occur within the phloem vessels.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0022-2011
    Keywords: Sitobion avenae; Erynia neoaphidis; rate of increase; fecundity; simulation
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: A collection of 87 ancient wheat genotypes, 67 Triticum monococcum, 13 Triticum boeoticum, seven Triticum urartu and one cultivar of the modern wheat Triticum aestivum (variety ‘Arminda’) were evaluated for resistance to the cereal aphid Sitobion avenae, the main damaging aphid pest on winter wheat in Europe. The intrinsic rate of natural increase (rm), which is regarded as a good estimate of the fitness of an aphid population, was used as an indicator for the level of plant resistance. Differentiation of the 88 plant genotypes into four distinct groups was achieved with a cluster analysis of the rm values. The modern wheat ‘Arminda’ was more susceptible than any of the ancient wheat genotypes tested (rm= 0.24, i.e. the aphid population doubled every 2.6 days). A second group of 19 plants ranged from relatively susceptible to moderately resistant (0.17 〈 rm 〈 0.21). Fifty–one plants were allocated to a third group and classified as resistant (0.09 〈 rm 〈 0.16). The last group contained 17 genotypes with a high level of resistance where aphid fitness was greatly reduced (0.02 〈 rm 〈 0.09, i.e. the aphid population doubled every 11.4 days or 7.7 days, respectively). Clustering of the accessions into the different phenetic groups did not follow the geographical origin of the wheat genotypes or the species to which they belong. These results show that ancient diploid wheats, all characterized by the genome A, present considerable interest for plant breeding for resistance to S. avenae in modern wheat. The potential use of these strong and partial sources of resistance for introduction of a stable and durable form of resistance to S. avenae in wheat is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: In order to establish whether commercial hybrid seed production between apetalous and apetalous rapeseed lines could be developed through insect cross-pollination, observations were made to compare the foraging behaviour of honeybees on both flower types with regard to their attractiveness. Number of flowers/m2 and nectar volumes, considered as important attractive factors, did not differ between the two lines but nectar sugar composition was slightly different. Honeybee density was significantly higher on the apetalous line when their foraging activity was rather high. Honeybees showed a considerable constancy to each flower type. Passages between both types were not very frequent. Nectar foraging behaviour, observed under cages, differed with the floral morphology. On the apetalous flowers, honeybees visited the two inner nectaries by crawling over the anthers and the stigma, while on the apetalous ones they often inserted their tongues between the sepals, thus having less contact with the reproductive organs. From these results, the honeybee efficiency in cross-pollination between petalous and apetalous lines appears to be reduced.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2018-11-13
    Electronic ISSN: 2045-2322
    Topics: Natural Sciences in General
    Published by Springer Nature
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...