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The Relationship Between the Ratio of Apex Size to Wing Size of Pieris rapae and Latitude

Cabbage White Butterflies, or Pieris rapae vary greatly in appearance based on location. One difference is the size of apex melanization. Apex melanization is thought to have an effect on thermoregulation. Our research attempts to determine if there is a correlation between the ratio of apex size to wing size and latitude. Previous research did not utilize ratios of wing size and apex melanization size to compare butterflies from different latitudes. In order to compile data from an established range of latitudes, we will use the program IDigBio. These photographs will be downloaded and cleaned to provide the necessary data. Then, they will be analyzed on ImageJ. We will measure and quantify data for the wing and apex size between our latitudinal ranges. After, we will compute their respective ratios. For each ratio, the latitude will be noted and will be used to generate a line graph on Excel to visualize our results. We will keep other variables as controlled as possible by using only images from IDIGBIO. We will also compute the standard deviation and p-value to determine the significance of our results. We expect the ratio of apex size to wing size in Pieris rapae will increase as latitude becomes closer to zero degrees. This is because with warmer temperatures, less light will be reflected to the body. This new evidence will allow scientists to further prove how Pieris rapae have adapted to different habitats. It will also show there is more intraspecific diversity closer to the equator.

Amanda Courtemanche '24, Lauren Parziale '23
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