Nest of a black stem borer (IMAGE) University of Freiburg Caption Nest of a black stem borer (Xylosandrus germanus) in a hazelnut branch with adult females (large), a male (small) and individual larvae. The greyish fungal coating of the food fungus is visible on the walls of the tunnel system. Credit Antonio Gugliuzzo Usage Restrictions University of Freiburg License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.