How we survey
UV flashlights
The primary method we employ is to go out after sunset, ultraviolet (UV) flashlights in hand, in search of caterpillars that fluoresce. Many caterpillar species fluoresce when UV light is shined on them. This type of fluoresecence is called UVIVF (Ultraviolet induced visible fluorescence). The fluorescence produced by caterpillars isn't very bright, so is much easier to see after dark.
Visual searches
We occasionally do daytime sessions to search for minute species of caterpillars that feed within leaves or other plant parts, or manipulate leaves in various ways to create shelters.
Beating sheets
From time to time we employ beating sheets, either during the daytime or after sunset. This has proven to be a useful addition to our toolkit of surveying methods.
Example of a caterpillar fluorescing
(Photos taken in High Park)
Sphinx Moth
Photo taken at night with a flash
Same individual fluorescing as UV light is shined on it (blurry photo due to being taken handheld at a slow shutter speed)