Quantifying Insect Movement in the Field

We describe a method of quantifying insect paths in the field for use in ecological and behavioral studies. First, we discuss how continuous and curvilinear paths traced by moving insects can be approximated with a series of connected straight lines. Next we describe our procedure for following insects under field conditions and for recording their behaviors (and the timing of behavioral events) with a hand-held TRS-80 computer. We discuss how successive positions of a followed insect can be recorded by triangulation and then translated into spatial coordinates. Finally, we illustrate the method with a study of individual movements in a hilltopping butterfly, Euphydryas editha Boisduval.