THE RESPONSE OF THE WHITE-PINE WEEVIL TO NATURALLY OCCURRING REPELLENTS

Abstract

The reactions of the white-pine weevil to air-borne repellents was studied in an olfactometer which, unlike other types, permitted a quantitative measure, capable of gradation, to be made of an individual's response. Different coniferous tree species supplied the odorous material in the form of essential oils extracted for use in these experiments by distillation from the bark. Degree of oil repellency and tree species were related. The response of any one individual tended to be consistent. Males and females responded equally to the repellents. The curve relating the response and the concentration of the repellent was similar to those generally describing the relation between stimulus strength and response. Adaptation to the repellent odors was clearly seen. From analysis of motion picture film it was apparent that repellent vapors affected weevil behavior so that the duration of activity periods was shortened although the rest periods remained constant.