Investigating the Role of Pepck2 in Feeding Behaviors of Female Virgin Drosophila melanogaster in Various Social Densities

• Julia Rusinski, Biological Sciences, University of Delaware

• Lisha Shao, Biological Sciences, University of Delaware

It has been shown that living in social density extremes, such as very densely populated areas or social distancing protocols as practiced during the COVID-19 pandemic, negatively affects human behaviors. However, the neurobiological mechanisms for these effects have not yet been clearly demonstrated. Here, we used Drosophila melanogaster, the common fruit fly, as a model organism to answer this question. In a previous RNA sequencing study, we identified a gene, pepck2, whose transcription was upregulated in isolated conditions but downregulated in crowded conditions, suggesting that it may play an essential role in animals’ reaction and adaptation to social stress.The current research aims to elucidate the effect of pepck2 on the feeding behaviors of virgin female Drosophila melanogaster in conditions of average social density, overcrowding, and isolation. Groups of Drosophila melanogaster with a mutated copy of the pepck2 gene were conditioned in one of the above social densities for five days. To quantify feeding behavior, the flies then fed on dyed food for 24 hours. Total consumption was extrapolated by measuring the quantity of dye both inside the fly and excreted by the fly. No significant difference has been found in total consumption between the social densities within the current sample size; both isolated flies and overcrowded flies consumed a similar amount to the control. This is a change in behavior compared to flies with an unmutated copy of pepck2, in which isolated flies ate significantly less than both the control and the overcrowded flies. However, further experiments are required to obtain a sufficient sample size. Because pepck2 has homologous human genes, studying pepck2 in Drosophila melanogaster can offer insight as to the neurobiological mechanisms for human feeding behaviors in social density situations similar to those explored in this study.