1. Acknowledgments Franny Gilman, Riccardo Ton, Stephen Antonich, and My Friends and Family Introduction Artificial light has distorted the nighttime environment and has altered the survivability of insects. Finding which wavelength of light each order of insects preferred could have huge repercussions in the protection of beneficial insects. Insects are the base of the predator-prey food pyramid and its disruption would cause problems for all organisms. The insect orders caddisflies (Trichoptera), moths (Lepidoptera) and mayflies (Ephemeroptera) were examined. Hypothesis: Each insect order will prefer a different wavelength of light. Null Hypothesis: All the insect orders will prefer the same wavelength of light. Abstract. It is important to identify characteristics unique to different types of insects. This could help in efforts to protect beneficial insects. The insect orders caddisflies (Trichoptera), moths (Lepidoptera) and mayflies (Ephemeroptera) were examined to determine what wavelength is most attractive to each insect order and how they differ in their interaction with their preferred light source. This study looks at insect orders separately rather than grouping them all together as seen in previous studies. It was conducted at night, by shining, a flood light on a white sheet to determine how many insects landed on the sheet. The sheet was observed for 30- minute intervals and then the insects were allowed to disperse for an additional 30 minutes. The color of the light source was then changed to encompass the wavelength range from 450 nm to 750 nm, or in other words from blue to red in the visual spectrum. The results show that all these orders have a preference toward the shorter wavelengths and have less preference toward longer wavelengths. Additional data is needed in order to make a more detailed conclusion, including how different insect orders act at their preferred wavelength. Materials and Methods Performed in the Rattlesnake Wilderness of Missoula Montana A flood light was enclosed in a white pillowcase Five different colored transparent plates as coverings for the floodlight The plates colors were red, blue, yellow, green, and a clear plate. The clear plate allows white light for a control Insects were counted, based on their order as they landed on the pillowcase in 30-minute intervals Insects were captured, identified, and then released so the correct order was assigned Insects were then allowed to disperse for 30-minutes The light covering was switched and the process repeated Results As shown by the graphs, blue and green wavelengths attracted the most insects in all three orders As shown by the graphs, yellow and red wavelengths attracted the least number of insects in all three orders White contains all wavelengths of light and can be used as a control to compare with the other wavelengths Discussion and Conclusions By the results my hypothesis was rejected but the null hypothesis was failed to be rejected. The data indicates that the three orders of insects all prefer blue and green wavelengths much more then yellow and red wavelengths. Insects are important for an ecosystem to thrive. As the base of the predator-prey food pyramid it is important to protect insects. These three orders of insects cause no harm to humans an effort should be made to protect them. One way to protect the insect orders Trichoptera, Lepidoptera, and Ephemeroptera is by using yellow or red lights outside our houses. It would have been beneficial to have determined the specific wavelength that each of the orders preferred rather than simply a range of wavelengths that is within a specific color. Additional research should be conducted using equipment that could produce and calculate exact wavelengths. Unfortunately, the equipment available in this experiment was not that sophisticated. As stated in the abstract additional data is necessary to determine how the insect orders Trichoptera, Lepidoptera, and Ephemeroptera react during their exposure to their preferred wavelength of light. 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The influence of moonlight on the activity of certain nocturnal insects, particularly of the family Noctuidae, as indicated by a light trap. Philosophical Transactions of the Royal Society of London.Series B, Biological Sciences 226:357-389. Michael Conner Weston, Biology, University of Montana Figure 1- White Plate covering, shining through pillowcase. Figure 2- Red Plate covering, shining through pillowcase Photo: Simone Depeak Photo: FCPS