Sökning: "weevils"

Visar resultat 1 - 5 av 13 avhandlingar innehållade ordet weevils.

  1. 1. Evolution of asexuality in insects : Polyploidy, hybridization and geographical parthenogenesis

    Författare :Magnus Lundmark; Anssi Saura; Anders Nilsson; Davis Parker; Umeå universitet; []
    Nyckelord :Molecular genetics; weevils; geographical parthenogenesis; hybridization; polyploidy; Genetik; Otiorhynchus; Genetics; genetik;

    Sammanfattning : Asexual reproduction and polyploidy are relatively rare in animals with chromosomal sex determination and always represent a derived condition. To accomplish asexual reproduction several changes in gene expression are required in the mechanism of oogenesis. LÄS MER

  3. 2. Interactions between ants and pine weevils : effects on forest regeneration

    Författare :Vita Manak; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Ants interact with plants in various ways and ant presence on plants can decrease local abundance or activity of herbivores, which in turn increases plant fitness. Red wood ants (Formica rufa group) are common species in forests of northern Europe. LÄS MER

  4. 3. Exploiting plant defenses to protect conifer seedlings against pine weevils

    Författare :Yayuan Chen; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

    Sammanfattning : Sweden is one of the top five countries having large planted forest areas, and here the forests are maintained by clear-cut regime, which also promotes the pine weevil (Hylobius abietis), a major threat to Swedish planted coniferous regeneration. Given interest in developing sustainable forest management practices, efficient non-insecticide alternatives are highly demanded to tackle the pine weevil problem. LÄS MER

  5. 4. Volatiles of Conifer Seedlings : Compositions and Resistance Markers

    Författare :Astrid Kännaste; Anna-Karin Borg-Karlson; Anders Backlund; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Conifers; Norway spruce; Scots pine; Nalepella; Oligonychus ununguis; green leaf volatiles; terpenes; aromatics; benzenoids; SPME; induced defense reaction; Organic chemistry; Organisk kemi;

    Sammanfattning : Pine weevils cause major damage to newly planted conifer seedlings in reforestation areas. However, recent findings indicate that small (“mini”) seedlings, planted at the age of 7-10 weeks, are gnawed less by pine weevils than the larger, conventionally planted seedlings. LÄS MER

  7. 5. Pine weevil feeding behaviour in relation to conifer plant properties

    Författare :Frauke Fedderwitz; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

    Sammanfattning : The pine weevil (Hylobius abietis (L.)) is a forest insect distributed over the Palearctic region. The adults feed on the phloem of young conifer plants causing high economic losses for the European forest industry. Still, there is very little knowledge about the structure of its feeding behaviour. LÄS MER