The middle crown and south quadrant of 6-m-tall jack pines, Pinus banksiana Lamb., produced significantly more cones than the rest of the tree. The number of cones attacked by Eucosma monitorana Heinrich was also highest in the middle crown and south quadrant. Laspeyresia toreuta (Grote) attacked the most cones in the middle crown. A positive, linear correlation existed between the number of cones attacked by inseets and cone abundanee per tree, indicating a response of the insect population to inereased food supply.
Rauf, Aunu and Benjamin, D M.
"Spatial Distribution of Jack Pine Cones and Those Attacked by Insects,"
The Great Lakes Entomologist: Vol. 16
, Article 16.
Available at: http://scholar.valpo.edu/tgle/vol16/iss4/16