Bark beetles have a decisive impact on fungal communities in Norway spruce stem sections

• We study the importance of insects for establishment of fungi.
• We analyzed wood and bark beetle sample after one and two flying seasons.
• The samples were molecularly analysed for fungal communities (454-sequencing).
• Mimic bark beetle holes in dead wood had a minor effect on the fungal community.
• Several white rot species were significant higher in logs with bark beetle access.

To study the importance of insects in the establishment of fungi, stem sections of Norway spruce were placed in mature managed conifer forests in Southeast Sweden. After one or two flying seasons, fungal communities in wood, bark and bark beetle samples were analysed by molecular methods. Excluding insects from stem sections with cages had a significant effect on the fungal community. Small wounds made in the bark to mimic insect activity did not significantly alter the fungal community, indicating that physical holes as such only played a minor role for the insect interaction with the fungal community development. Several white rot species were significantly more abundant in stem sections with insect access and were also detected from bark beetle samples. This suggests that insects do contribute to the development of early fungal succession on dead wood, but that creating small disturbances in the bark only have a minor contributing effect.