To locate individual mosquitoes, light from the flashlights hits the tank across the room, creating tiny mosquito silhouettes on reflective material behind it. The zoom lens picks up the shadows and feeds the data to the computer, which controls the laser and fires it at the bug.
A mosquito hovers into view. Suddenly, it bursts into flame. A thin plume of smoke rises as the mosquito falls. At the bottom of the screen, the carcass smolders.