Corthylus punctatissimus, the pitted ambrosia beetle, infested and killed maple saplings that were 3-12 years of age with a basal diameter of 4-14 mm. The habits of the parental pair of adults are described. The beetles construct a spiral gallery system with about five egg niches per host. Half the brood reaches adult stage during the summer with a sex ratio of 1:1. No relationship was found between the number of niches, length of gallery system, or diameter of stem.
Roeper, Richard A.; Palik, Brian J.; Zestos, Demetrios V.; Hesch, Patrick G.; and Larsen, Celia Duke
"Observations of the Habits of Corthylus Punctatissimus (Coleoptera: Scolytidae) Infesting Maple Saplings in Central Michigan,"
The Great Lakes Entomologist, vol 20
Available at: https://scholar.valpo.edu/tgle/vol20/iss4/1