Abstract
This study involves five bark beetle species (2 mycangial/aggressive species and 3 non-mycangial secondary species), all regarded as serous pests in conifers forests. Two main hypothesis will be tested i) all bark beetles, regardless of ecology benefit from feeding fungi and ii) only mycangial fungi increase nitrogen in the phloem. The study is divided into 4 objectives. Objective 1 determines where the fungi are carried by the bark beetle adult (on exoskeleton, in gut or in mycangia (if present)). In objective 2 we analyze what fungi the beetle feed upon during the larval development. In both cases molecular tools such as DNA-extraction, PCR-reaction and mass sequencing are used to gain DNA-sequences before comparison against a known fungal database. In objective 3 galleries from objective 2 will be analyzed of nitrogen content in order to study which fungi are capable of concentrating nitrogen. In objective 4, logs are inoculated with fungal specie from objective 1-3 and will be pheromone bated and placed in the forest during the bark beetle flight season and sampled during pupae phase. The logs are analyzed according to how the fungi affect larvae growth and size of the adult beetle. At least three scientific papers describing the fungal communities associated with these insects the mode of transport of the associates, the degree of dependence of non-mycangial beetles on fungi, and the relative contribution of fungal associates to nitrogen provisioning for host beetles.
Sweden