Fruit Fly Lab Report

A Demonstration of Chemotaxis Between Flies and Various Substances (Sugar vs Bacteria)

Abstract: The purpose of this lab based on the Drosophila melanogaster (the common fruit fly) reactions. Since the fly has been studied and observed for many years, and known for its unique chemotactic attractions to different stimuli, it was an ideal organism for the study being conducted. In the experiment the purpose was to be able to figure out whether the flies would be more attracted to sugar or bacteria. The bacteria, which is found in flies’ natural food source rotting fruit, was represented by the yeast, and the sugar was represented by the maple syrup. The purpose was to be able to identify which substances the flies were attracted to the most

Through concise analysis of research papers and other experiments conducted elsewhere, the final conclusion of this lab was supported. All in all, the inquiry experiment allowed the accomplishment of the goal of identifying one of the main reasons why fruit flies eat rotten fruit.

Introduction:
Drosophila (a model research organism) melanogaster (black abdomen) is the common fruitfly. The lab required the usage of fruit flies as they are a commonly used organism in many experiments. The portion before the inquiry lab utilized the usage of different foods to determine exactly which food the flies would experience more of an attraction towards. From the chi square calculations and analysis of the inquiry lab, the flies were found to be highly attracted to sugary foods such as jam, as opposed to sugarless substances like taco sauce, which would later determine exactly what the inquiry

The table seemed slightly imbalanced, and since the flies demonstrate a negative geotaxis, meaning that they resist gravity, the flies may have been influenced to choose one side over another simply by gravitational means. Another error that may have occurred could be the source of light. Though the lab group aimed to maintain an equal amount of light for all sides of the bottles, a vaguely estimated spot was determined and the choice chamber placed there. Since fruit flies also demonstrate a positive phototaxis, this also affects them. The last error that may have occurred due to tape. Though caution was emphasized, and extreme carefulness had been placed in the taping process, some tape may have gotten inside the bottle, and fruit flies may have been stuck to it, which had skewed data.
The lab manual from College Board, which states, “The common fruit fly….feeds on the fungi of rotting fruit,” (College Board 2004) reinforces the hypothesis clearly, and depicts chi square values with values such as 18.75. Experiments performed in UC Davis show that “fruit flies are regularly trapped….by yeast, and “the chemicals released by microbes….[attracted] more flies.” (Garvey 2014) Some ways to improve the lab are to make sure that the error sources are fixed. Next time, it should be imperative that the table being used is perfectly balanced and that the tape is not placed on the inside