New techniques for improving resolution and visual information on flight activity in Trichoptera

Abstract

Earlier design and use of photographic rigs for recording insects in free flight, and the applications and shortcomings of those efforts are reviewed. Improvements included the following: Replacement of laser beams with infrared (IR) LED beam-emitters and IR phototransistor detectors; an array of nine intersection points to increase the possibility of capturing images; improved electronic circuitry to avoid multiple image capture; more energy-efficient and smaller UV light sources to attract insects; a more rigid aluminium frame to support the UV and IR LED transmitters and detectors; development of an ultra-high-speed flash system 5 μs, or faster, to produce even sharper images than those produced by the 25 μs standard speedlight flash units set at 1/128^th power; and a transportable wooden box to house all the electronic components and mounts for cameras and speedlights. This paper describes the design features of the rig and its use in the field and illustrates and compares photographic results obtained using a variety of photographic techniques aimed at providing high quality, sharp, images of insects in free flight, continuous traces of the flight pattern of insects, strobe images, and combinations of these techniques. From these images reasonably accurate estimates of insect size, wing beat frequency, flight speed, and information on mechanics of flight can be obtained.