Photo of Bruce and Theo collecting insects at night

Featured student project: Theo Black

Many aquatic insects use polarized light to find water surfaces on which they reproduce, and where their larvae live and grow.  Manmade objects and structures can sometimes mimic these water surfaces by polarizing light. Moreover, in some cases they can be more attractive to aquatic insects than water itself. This effect causes “ecological traps” that can lead aquatic insects to population decline or even extinction.

Previous studies have shown that the attractiveness of polarizing synthetic surfaces can be reduced if grids of non-polarizing lines are strategically placed on them. In his senior project, Theodore Black measured the effect of line thickness on the attractiveness of polarizing non-water surfaces. Early in the morning he would install his polarizing traps near the water stream, and late at night he would collect them. Then, for days and days, he would sort and identify insects trapped in oil under the microscope, classifying them into such poetically named groups as non-biting midges (Chironomidae), black flies (Simulliidea), caddisflies (Trichoptera), and mayflies (Ephemeroptera). This work allowed Theo to analyze and describe the effect of non-polarizing line thickness on the attractiveness of traps, which will help to protect aquatic insects from human interference. Using this new information, engineers will be able to design solar panels that are efficient, yet don’t trick aquatic insects into laying eggs on it, helping them to avoid an evolutionary trap.