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Completed Project

Blue Light Stimulates Nematodes: A Study of C. elegans Behavior Using Continuous Wave Lasers

Ramy Abbady, Vassar College ’16, Caitlin Bell, Vassar College ’15 and Profs. Kathleen M. Raley-Susman and Jenny Magnes

C. elegans is a soil-dwelling nematode that serves as an important model organism in the biological sciences. Recently, scientists have discovered that C. elegans can detect light, despite lacking eyes. Our aim was to confirm the reaction of C. elegans in response to blue wavelengths of light. Because our past research has shown that C. elegans do not react to red light, we used this as our control. We placed individual nematodes in water-filled cuvettes, and measured their swimming behavior using laser diffraction and a photodiode. As nematodes move, the diffraction pattern changes, and we can calculate their swimming rate based on our measurements of this diffraction pattern. We found that C. elegans move an average of ~0.3 Hz faster in blue (447 nm) light as compared to red (633 nm) light. This indicates that C. elegans do detect blue light, and swim faster to avoid shorter wavelengths of light. We also looked at the effects of changes in light intensity on C. elegans swimming, but we did not find a statistically significant difference in swimming rates for blue light. Future studies will include examining C. elegans’ responses to other wavelengths of light, including both intermediate wavelengths between the two we studied and even shorter wavelengths in the ultraviolet range.