An Effect of Aggregation on the Behavior of a Beetle (Conophthorus coniperda Sz) in a Temperature Gradient

The white pine cone beetle (Conophthorus coniperda Sz., Scolytidae) infests the twigs and cones of white pine throughout its range in eastern North America. The insects pass the winter in the adult stage within abortive cones on the forest floor. In spring, the adults emerge and move to the tops of the trees where they infest the current cone crop. Eggs are deposited in the growing cones and the life history is completed within the brood cones during the period from early spring to midsummer.8 The only period in its life history when the insect is free-living and active is during the move from the abortive brood cones on the forest floor to the cones of the subsequent crop. This situation is particularly interesting in that the entire dispersive and distributional pattern of the insect must be established for each generation within a very short period. This report is concerned with a behavioral mechanism which is probably of considerable importance in determining the distribution of the insect.