A Continously Recording Flight Mill for Investigating the Effect of Volatile Substances on the Flight of Tethered Insects1

An apparatus was developed to test and record the effect of volatile substances on the flight of tethered insects. It consists of a rotary flight mill within a glass chamber through which there is a continuous air flow, and a photocell-ratemeter-paper chart recording system. This system provides a permanent quantitative record of flight speed and duration and shows immediate and subtle changes in flight speed. The apparatus can be adapted for computer programming by a digital voltmeter and tape punch. Introduction of sex pheromone (as female frass) into the flight chamber caused male Douglas-fir beetles, Dendroctonus pseudotsugae Hopkins, and striped ambrosia beetles, Trypodendron lineatum (Olivier), to cease flight abruptly. This is considered to be strong evidence for the arrestant effect of pheromones on flying scolytids. The apparatus has promise as a tool in the study of the effect of pheromones and volatile host attractants on flying insects.