A monogamous pair of adult Trypodendron retusum construct a gallery system consisting of an entrance tunnel and from two to five lateral tunnels into the sapwood of aspen. Inoculation of the mutualistic fungus Ambrosiella ferruginea by the female beetle, was followed by oviposition in shallow egg cradles. Two instars were observed as the larvae enlarged their cradles. The number of cradles per gallery system was correlated to the length of the gallery system. Progeny adults with a sex ratio of approximately 1:1 emerged from late June to early August to overwinter in the litter.
Brewer, Steven D.; Beck, Robert A.; and Roeper, Richard A.
"Observations of the Gallery Habits of Trypodendron Retusum (Coleoptera: Scolytidae) Infesting Aspen in Central Michigan,"
The Great Lakes Entomologist, vol 21
Available at: https://scholar.valpo.edu/tgle/vol21/iss1/2