Effect Of Photopollution On The Activity Of Drosophila Melanogaster

An organism’s endogenous circadian clocks synchronize with the environment to regulate many physiological functions. These clocks are set by light cues from the sun coordinating their rhythms with the 24 hour light-dark cycle. Recently, an ever increasing amount of artificial light is being used in our cities and towns, impacting the coordination between our circadian clocks and the environment. Photopollution describes the adverse physiological effects of increased artificial light on organisms. Photopollution has been found to impact numerous biological and ecological processes, such as overall activity, navigation, and reproduction. To further explore the impact of photopollution on organismal activity patterns, we utilized Drosophila melanogaster as a model system. Two groups of flies were analyzed: the first group was held in a regular light-dark cycle (LD), and the second was held in a light-low light cycle (LLC) of 2 lux. TriKinetics activity monitors were used for a total of five days to analyze the change in activity between the two different light environments. The activity monitors were able to record fly activity every minute for the duration of the experiment. Follow up experiments increased the low-light cycle to 27 lux to further replicate levels of photopollution found in the Chicagoland area (0 to 36 lux). Furthermore, temperature was used as a secondary variable to determine whether being exposed to varying environmental temperatures had a different impact on the LLC flies compared to the LD flies. A Thermochron temperature logger was used to measure the temperature throughout the course of the experiment. Preliminary data suggests the activity of both male and female flies differed between the LD and the LLC environments in both 2 lux and 27 lux. The LLC condition showed significant differences in their patterns of rest and activity, where their phases of activity expanded. Furthermore, male activity significantly differed from female activity. Temperature data suggests the LLC flies did not adapt as well to environmental temperature changes as did the LD flies. This research is important because it will not only develop a new model system for studying photopollution, but it will also help further our understanding of the impact of photopollution on circadian clocks, behavior, and the environment