Canadian Forest Service Publications

The spatial distribution of cocoons of Neodiprion swainei Middleton in a jack pine stand. 1. A cartographic analysis of cocoon distribution, with special reference to predation by small mammals. 1966. McLeod, J.M. The Canadian Entomologist 98(4): 430-447.

Year: 1966

Issued by: Laurentian Forestry Centre

Catalog ID: 15571

Language: English

Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.4039/Ent98430-4

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Insight into the source of aggregation in the spatial distribution of cocoons of the Swaine jack-pine sawfly, Neodiprion swainei Middleton was gained by the use of special techniques enabling the sampling of units of forest floor in contiguous 2 × 2-inch square samples, as well as by randomized one-square-foot samples taken over a larger area. It was concluded that cocoon distribution is initially random but marked aggregation results from the subsequent transportation of cocoons into feeding stations by predacious small mammals, mostly of the genus Sorex. The feeding stations tended to be distributed near decaying stems and stumps on the forest floor, a factor which augmented the extent of aggregation. Of cocoons not preyed upon by small mammals, slightly higher counts were recorded directly under crown canopies as opposed to open areas, at a tree density of approximately 920 per acre.