Sperm Precedence in the Hermaphroditic Freshwater Snail, Helisoma trivolvis



Project Description

The project was to determine sperm precedence of first mate in hermaphroditic freshwater snails using albino snails for a clear trait marker in the eggs.




Morgan Wright '14

Morgan Wright ’14 wanted to do some research in her major, biology. She found Cindy Norton who was ready to work on something new. From general biology lab work, Cindy had been noticing interesting results of existing projects and decided to study sperm precedence in the hermaphroditic freshwater snail, Helisoma trivolvis. The study involved mating albino and non-albino snails to provide a genetic marker to determine which sperm were used to fertilize the most eggs. This involved a lot of scope work in order to count how many eggs in an egg mass had eye pigmentation and how many did not. This could include up to 250-350 eggs a week. The results showed that the first mate had a higher sperm precedence.

Morgan had a lot of fun working with Cindy. “It wasn’t just grunt work,” Morgan states. They collected and analyzed the data together and determined which questions to focus on for the project. They even began collecting data in the first week of the program. Morgan learned a lot about what is involved in research when live specimens are involved. One of the issues that arose this summer was a temperature issue, warmer temperatures than usual caused the eggs to develop faster and since the window of time for being able to easily count the eggs’ eye pigmentation is short, the timing of their research took on its own life.

Morgan would recommend Summer Scholars to all students; it was a very supportive program and really helped in allowing her to focus on research for the summer instead of getting another job. She knows this will help draw positive attention to her graduate school application as well as an application for the National Science Foundation Research Experience for Undergraduates.


  • Application for the National Science Foundation Research Experience for Undergraduates.

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