Dr. John D. Detwiler was an educator born in Roseville, Ontario on July 21, 1878. He was educated at Galt Collegiate Institute, Queens University and the University of Western Ontario. He was a teacher in public and high schools, and became an instructor of entomology and rural education at Cornell University, 1918-1921. At the University of Western Ontario he was assistant professor of zoology 1921-1925, associate professor 1925-1929, professor of applied biology 1929-1946, head of the Department of Applied Biology 1946-1949. He retired in 1949.

Detwiler also acted for a number of years as an investigator for the Biological Board of Canada, the Dept. of Mines and Fisheries, and the Dept. of Game and Fisheries. He served as President of the Canadian Conservation Association 1940-1951.

Detwiler married Hughena Mackenzie Campbell on July 12, 1919. After his retirement he lived in Ayr, Ont. where he died on Aug. 30, 1966.