Species of the genus Ips De Geer are polygamous and the number of females in a gallery map vary from one to five, or occasionally six, to one male. Populations of Ips tridens Mann. going into hibernation in the fall of the year in Alberta, have a sex ratio of approximatclv 3 ♂ ♂: 1 ♀. The assumption has been that the preponderance of fenlales is caused by some mortality factor which is more effective against the males. More recent evidence indicates that the cause is of a genetical nature.
Email your librarian or administrator to recommend adding this journal to your organisation's collection.