Vivlar på prydnadsbuskar - nya arter eller förändringar i födopreferenser?

Detta är en Kandidat-uppsats från SLU/Department of Plant Protection Biology

Sammanfattning: During the last couple of years leaf-edge-cuts, typical to Otiorhynchus wingless-weevils, have been discovered on ornamental shrubs, especially Syringa vulgaris lilac and Ligustrum vulgare privet. These plant species have not earlier been attacked by wingless-weevils and because of that, the aim of this study is to see if new species of weevils have been established in Sweden or if the domestic weevils have changed their food preferences. This work also includes a literature study of known weevil species in Sweden and their host plants, and of wingless-weevil species in Europe that could be invasive here. Locations, where damage to previously named plants has been reported, have been examined. The extension and appearances of the damages have been documented in order to study if different weevil species make different types of edge-cuts. Weevils have been collected to be defined as species. The results show that we in Sweden have a completely new species of wingless-weevil, Dodecastichus inflatus (former known as Otiorhynchus inflatus), which has not earlier been reported from our country or its immediate surroundings. The most northern location for this weevil in Europe was earlier Gdansk. In this study we have shown that D. inflatus is established in Helsingborg. Further more, the weevil Otiorhynchus smreczynskii has in this study been shown to be established in a much larger geographic area than previously known. This species has occasionally been found in the region of Malmö, but now O. smreczynskii was found all along the west coast of Scania up to Helsingborg. This species was the most common on lilac and privet and caused the majority of the damage. The wingless-weevils are causing extensive damage to plants, the adults attacking the leaves and the larvae attacking the roots, which negatively affects the condition of the plants. If massive attacks occur in a nursery, the economical consequences could be significant. To be able to give qualified advice in the future to both nurseries and private gardens, additional studies of weevils on ornamental shrubs should start immediately. The distribution of these weevil species in Sweden and their ability to establish and reproduce need further investigation. ------------------------------------------------------------------

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