Trypodendron retusum Leconte attack pattern on Populus grandidentata Michx. (Big Tooth Aspen) was studied. Mating habits of males and females involved copulation at the entrance hole bored by the female. Attack (entrance )holes averaged 15.9 cm. apart and were found to be uniformly spaced on the bark surface. Attack density was greater on standing trees than wind-thrown trees. On standing trees attack density appeared to be a function of the height rather than the diameter of the tree.
Roeper, Richard; Dickerson, Daniel; Kurtzhals, Paul; Bunce, Mark; and Brewer, Steven
"Observations of the Mating habits and Attack Pattern of Trypodendron retusum (Coleoptera: Curculionidae: Scolytinae) on Populus grandidentata in Central Michigan,"
The Great Lakes Entomologist, vol 55
Available at: https://scholar.valpo.edu/tgle/vol55/iss1/7