Trypodendron betulae Swaine distributed attack entrance holes uniformly over the surface of standing stressed sub-canopy birch trees. Male and female pairs constructed galleries consisting of an entrance tunnel about 20 mm in length and then primary and secondary lateral tunnels averaging between 16 and 23 mm in length into the sapwood. Egg niches were constructed in the lateral tunnels after the symbiotic fungus was established in the galleries. Larvae enlarged the niches into cradles. Pupae and eventually teneral adults developed in the cradles. The sex ratio of resulting progeny adults was approximately one to one, and they emerged from galleries in September to overwinter in the litter.
Roeper, Richard A.; Allen, Michael; Hutchinson, Teresa; Quidot, Corrina; and Bunce, Mark
"Gallery Characteristics and Life History of the Ambrosia Beetle Trypodendron betulae (Coleoptera: Curculionidae: Scolytinae) in Birch,"
The Great Lakes Entomologist, vol 48
Available at: https://scholar.valpo.edu/tgle/vol48/iss3/9