Canadian Forest Service Publications
The effect of metamorphosis on the multiplication of an insect virus. 1953. Bird, F.T. Canadian Journal of Zoology 31:300-303.
Issued by: Great Lakes Forestry Centre
Catalog ID: 34306
Availability: PDF (request by e-mail)
The prepupal stage of the European spruce saw fly is immune to infection by a polyhedral virus disease. The virus multiplies only in the nuclei of the digestive cells of the mid-gut epithelium and during metamorphosis these are replaced by embryonic cells not susceptible to infection although they develop into digestive cells eventually. The prepupal mid-gut, a temporary gut, is composed entirely of embryonic cells. New digestive cells appear later in the pupal and adult stages and these rapidly become infected with virus.