Wild-type and <i>ort1</i> mutant <i>Drosophila melanogaster</i> spend a varying amount of time in different light intensities

Abstract

Drosophila melanogaster have photoreceptors in their eyes that allow them to respond to different light intensities. The ort¹ mutants have these photoreceptors, but are missing the R1-R6 rhabdomeres in them. This mutation disrupts the communication between the organisms’ lamina cells and photoreceptors. The focus of our experiment was to compare the proportion of time spent in different light intensities in the wild-type and ort¹ mutant D. melanogaster. We tested two light intensity treatments in the arms of a T-maze: dim light intensity (≤ 0.05 lux) and high light intensity (> 0.05 lux). We then recorded the time that 40 wild type and 40 ort¹ mutants spent at each light intensity over 30 seconds. Our hypothesis was that light intensity will affect the time spent under varying light conditions in the wild type and ort¹ mutants of Drosophila melanogaster. We found that 73% of wild-type flies spent more than 15 seconds in the dim light location, while only 5% of ort¹ mutants preferred staying in the dim light arm of the T-maze. We used Fisher’s exact test to analyse our data, and found the difference in choice between the wild type and ort¹ mutants to be statistically significant (p = 0.0001). The lack of R1-R6 rhabdomeres affects the ort¹ mutants’ ability to detect dim light and relay the information to the brain and this may cause the flies to ignore low light regions.