Toxic wavelength of blue light changes as insects grow
SUMMARY: Different wavelengths of light are toxic to insects. In this study, scientists looked at the different effects of blue light on fruit flies (Drosophila). They found that each developmental stage was more susceptible to different wavelengths. There were also differences between males and females. For eggs, the most lethal wavelength was 405nm. For larvae, it was 405-466nm. For pupae, it was 417-466nm. The adults were most resistant, so the scientists had to beam them for a few days. At 466nm, 94% of females died on day 6. 417, 439, and 466nm killed off 92%, 90%, and 100% of the males respectively on day 3. And on day 6, all wavelengths killed all males. The study also looked at hydrogen peroxide production and speculated that it was a possible mechanism for how blue light causes damage in drosophila.
LESSON COMMENTS: The article is great for both biology and physics students. Great questions to ask: Why is there a difference in the toxicity of light? What developmental stage was most susceptible and why?
The graphs are great for students to analyze and they should compare the quantitative results to the graphs to see if the data and visual representations match up. This is an important skill for students to learn since falsifying data or misrepresenting data is not unheard of.
Finally, the part about hydrogen peroxide should be discussed because hydrogen peroxide is produced during normal mitochondrial activity. The levels that the study gives doesn’t compare it with normal levels of either H2O2 or any other ROC species. Students can do their own research on what normal levels of ROC are in drosophila. This is a good article to start with: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4413513/
Shibuya, K., Onodera, S., & Hori, M. (2018). Toxic wavelength of blue light changes as insects grow. PloS one, 13(6), e0199266. doi:10.1371/journal.pone.0199266
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