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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 21 (1899), S. 940-941 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    Greece and Rome 10 (1963), S. 147-152 
    ISSN: 0017-3835
    Source: Cambridge Journals Digital Archives
    Topics: Archaeology , Classical Studies
    Notes: The essence of the adventure story is, above all, travel. If the author is to indulge his reader's taste for the wonderful and the marvellous, he must, if he is dealing with anyone but the most sophisticated reader of science-fiction, do it in a way that provides a scale against which the wonders may stand out. A strange being may be brought to familiar surroundings, or alternatively, and much more commonly, a neighbour, as it were, may be projected into a foreign environment, about which he later gives us his account.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1939
    Keywords: Acyrthosiphon pisum ; Migration ; Adaptation ; Photoperiod
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The purpose of the study was to quantify long distance movements in populations of pea aphid, Acyrthosiphon pisum (Harris), by estimating origins and distances travelled by immigrants into a southern Manitoba population. A strong relationship was demonstrated between latitude of origin and photoperiods at which pea aphid populations are stimulated to produce the diapause stage (Smith 1987). Therefore, the approach was to use photoperiodic response as a physiological marker to identify the source of immigrant aphids. The responses of 89 clones from Glenlea, Manitoba (49°38′N), sampled 5 times over 2 seasons, were measured. One sample of clones collected the first season had photoperiodic responses similar to those of a population about 300 km to the south, and significantly different from clones collected in spring of the same year at the same site. Weather analysis corroberates that the migrants were probably carried into Manitoba on a southerly flow of air during the previous 24 to 36 h.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1939
    Keywords: Developmental rate ; Adult weight ; Adaptation ; Temperature ; Acyrthosiphon pisum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Developmental rate and adult weight were studied at constant temperatures from 9.8 to 27.9°C for 18 clones from each of five populations of the pea aphid, Acyrthosiphon pisum (Harris), from locations between 39 and 53°N latitude in central North America. The response of developmental rate to temperature for each clone was accurately described by a three parameter non-linear equation. Adult weight usually decreased with increasing rearing temperature, but the shape of the response to temperature varied among clones. Variation in the developmental parameters was greater among clones within populations than among populations. No consistent trends were observed in the developmental parameters or adult weights either with latitude or the long term average temperatures at the locations. We conclude that previously reported geographic variation in the developmental threshold of this species, which was attributed to local adaptation, occurred either because the clones tested were not representative of the populations or because rearing methods differed among studies. The results are discussed in relation to the hypothesis that life history traits which are temperature sensitive are adapted to local thermal environments.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 45 (1987), S. 195-198 
    ISSN: 1570-7458
    Keywords: Acyrthosiphon pisum ; Acyrthosiphon kondoi ; alatae ; crowding ; competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 48 (1988), S. 117-125 
    ISSN: 1570-7458
    Keywords: Acyrthosiphon kondoi ; Acyrthosiphon pisum ; Medicago sativa ; genetics ; variation ; host resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Douze lignées d'Acyrthosiphon kondoi Shinji et d'A. pisum Harris ont été échantillonnées dans un petit champ de luzerne australien et leur variabilité génétique examinée en comparant les réponses à 3 cultivars de luzerne. De 7 à 8 caractères biologiques avaient été retenus pour chaque espèce. Les différences observées entre les réponses suivant la distribution de ces caractères chez les pucerons, ont montré que 3 à 7 clones génétiquement distincts étaient représentés dans les 12 lignées de chaque espèce. Nous en concluons que les populations de ces deux espèces de pucerons sont polymorphes en Australie, quoiqu'elles se multiplient d'une façon asexuée et aient été récemment introduites. Les réactions des pucerons aux 3 cultivars sont indiquées. Par suite de la variabilité génétique des réactions des plantes hôtes aux pucerons, des cultivars à résistance potentielle élevée devraient être exposés à un grand nombre de clones de pucerons pour confirmer la présence d'une résistance utilisable.
    Notes: Abstract Twelve lines of Acyrthosiphon kondoi Shinji and Acyrthosiphon pisum (Harris) were sampled from a small lucerne field in Australia and tested to assess genetic variation by measuring their responses to three lucerne cultivars. Seven or eight life history traits were assessed for each species. Differences in the responses of these traits to the cultivars revealed that three to seven genetically distinct clones were represented in the samples of 12 lines for each species. We conclude that the populations of these two aphids are variable in Australia, although they were recently introduced and reproduce asexually. The responses of the aphids to the three cultivars are described. Because of genetic variation in host plant responses of the aphids, cultivars with potential aphid resistance must be exposed to a large number of clones to confirm the presence of useful aphid resistance.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 51 (1989), S. 125-132 
    ISSN: 1570-7458
    Keywords: Acyrthosiphon pisum ; male aphids ; genetic variation ; alary-dimorphism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Le dimorphisme alaire mâle, — ou présence de mâle ailé et aptère —, s'observe à l'intérieur et en fonction des clones de A. pisum Harris. Notre objectif est de décrire la distribution et la fréquence de ces deux morphes. 143 clones de pucerons du pois ont été récoltés sur Medicago sativa dans quatre stations de la Grande Plaine d'Amérique du Nord, entre 44° 45′ et 53° 12′ N: à cinq reprises pendant deux saisons dans une station, et une fois dans chacune des 3 autres stations. Tous les clones, soumis à une photopériode courte: L14: D10 ou L13: D11 à 20 °C, ont produit quelques mâles. Les 8 échantillons ont donné à la fois des mâles aptères et ailés, et les observations dans les clones confortent les expériences. Trois classes de clones ont été formées à partir des morphes produits: mâles aptères seuls, mâles ailés seuls, ou quantités égales de chaque morphe. La fréquence par rapport à la distribution binomiale a été utilisée pour montrer que pour presque tous les clones produisant les deux morphes, les proportions étaient 1:1. Ces observations prouvent que la présence ou l'absence d'ailes est déterminée génétiquement, probablement par un gène diallélique lié au sexe. La fréquence des clones produisant uniquement des mâles aptères varie en fonction des populations examinées, ce qui laisse supposer une perte de panmixie à travers la Grande Plaine, quant au morphe des mâles.
    Notes: Abstract In a study of male alary dimorphism, clones of pea aphid, Acyrthosiphon pisum (Harris), were collected five times over two seasons in one location and once each from three other latitudes in the Great Plains region of North America. All clones produced some males when subjected to a short photoperiod (L14: D10 or L13: D11) at 20 °C. The presence of three distinct classes of clones based on the morph of males they produced (apterous only; alate only; apterous and alate in equal proportions) provides evidence for a genetic basis for the dimorphism. The relative frequencies of clones producing only apterous males varied geographically, providing some evidence to support the hypothesis that populations are not panmictic over the Great Plains region.
    Type of Medium: Electronic Resource
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