Does Protein Storage Regulate the Growth of Sexual Characters in a Model Pest Fly?

Valeriya Prytkova

Authors:  Valerie Prytkova, Clancy Short, Daniel Hahn

Faculty Mentor:  Dr. Daniel Hahn

College:  Agricultural and Life Sciences


Whether it be the large antlers of male deer or the brightly colored feathers of some male birds, secondary sexual characters are important for males to secure mates and pass on their genes. Salivary glands are secondary sexual characters in the Caribfly that can also play a fundamental role in courtship and securing mates. Manipulation of these traits could improve male mating success, increasing the efficiency of the Sterile Insect Technique (SIT). SIT is an environmentally safe method of pest-control that sterilizes males and releases them to compete with wild females. If a female only mates with sterile males, she will not produce viable eggs, eliminating the next generation of pests without the use of chemical insecticides. Attractive males are critical for successful SIT programs. Understanding the growth of the salivary glands is useful because males with larger salivary glands likely attract more females. The role of protein stores in secondary sexual organ growth is unclear. The gene lsp2 allows Caribflies to store dietary protein. I will knock down lsp2 transcript abundance using RNAi, then measure the growth of the testes (a primary sexual organ) and the salivary glands to test whether protein stores promote secondary sexual organ growth.

Poster Pitch

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22 Responses
  1. Michelle Hsia


    I love how you explained why your research was so important and why it was innovative in your video. I know little to nothing about agriculture, and the way you systematically provided information was super easy for me to follow. You are incredible! Great work!

    1. Valerie Prytkova


      I also know little to nothing about Agriculture, so we are in the same boat… Thanks for the lovely comment though! You are the best! 🙂


  2. Alexis Brake

    You are amazing, Valerie! Excellent poster and presentation! I was wondering, what is the role of lsp-2? How did you select this protein to study?

    1. Valerie Prytkova

      That is an awesome question. I did not want to go too in-depth in my video, but this is certainly a huge part of this project.
      Lsp-2 or larval serum protein 2 has been identified as the main protein store in the adult stage (Short, 2018). Adult protein feeding increases lsp2 abundance and increases reproductive behavior (Short, 2018). By knocking down lsp2 transcript abundance, we can test whether protein storage is also a signal for secondary sexual characteristic growth and development.

      Let me know if you have any other questions!


    1. Valerie Prytkova

      Thanks, Iris!!!

      My goal is to publish this in a paper, but there is only so much you can do with insignificant results… We will see what happens!

      Thank you for stopping by! 🙂


  3. Nicole Abruzzo

    Hi Valerie!
    I had heard of the sterile insect technique with respect to screwworm eradication, but I had never thought about the possibility of making it more efficient! Great work, you’re awesome 🙂

    1. Valerie Prytkova

      Nicole!! My fellow Entomology buddy!!
      I miss seeing you around the halls of good old Steinmetz… Hope you are doing well! 🙂
      Thanks for stopping by and checking out my work!


  4. Jude Flynn

    Amazing project! Your work is so interesting and your presentation made it super easy to follow and understand.

  5. Emilio Roig

    Really interesting I didn’t know much about the sterile insect technique. I’m not sure if you’ve considered a full knockout of the gene instead of a knockdown with RNAi but it may be worth looking into 🙂 Awesome work Valerie 🙂 You’re amazing

    1. Valerie Prytkova

      You are the best!! Yes, perhaps knocking out using CRISPR would give us better results. That is definitely something to consider in the future!
      Thanks for stopping by and checking out my work.

      You rock!


  6. Nick Manocchio

    Amazing as always, Valerie! If you say lsp-2 is the main protein store in adult flies, is it safe to assume that it is the main protein store in adolescent flies, as well? If protein stores are critical for sexual organ growth, and knockdown of lsp-2 did not show significant decrease in size of the salivary glands, this could mean a different protein is responsible for the sexual development of these flies.

    1. Valerie Prytkova


      It is possible that the energy is allocated toward growing the secondary sexual organs instead of storing it, which would explain why knocking down the lsp-2 gene still results in relatively large salivary glands (statistically not smaller than the control). It is also possible that our level of knockdown was not sufficient enough to see a statistical difference between the sizes of the salivary glands. Perhaps, like you mentioned, an entirely different pathway is responsible for the growth and development of the secondary sexual characters. There are many things we do not yet know, which opens an exciting door for future research!


  7. Brittany Blake


    You do a really wonderful job of breaking down your project, especially for someone like me who knows nothing about entomology! It was very easy to see the implications and logical steps you took to conduct your study. You mentioned that you did not see a significant different between regular flied and Lsp-2 knocked out flies. Do you have any ideas to expand on your research? Would you continue looking at Lsp-2 or try something else?

    1. Valerie Prytkova


      You are so sweet! Thank you for taking the time to check out my work!! There are definitely many different steps that can be taken to further this research. Perhaps investigating a different pathway and a different protein would be worth it. I would personally love to use a different method of gene-knockout such as CRISPR, as it is a little bit more efficient. I suspect that our level of gene-knockout was not significant enough to see physical changes! Knocking out the gene in pupae would also be an interesting project to pursue.

      Thank you so much for stopping by and taking the time to ask me a question. I appreciate it a lot! I hope you are staying safe (and sane!!) during this craziness!



  8. Valerie Prytkova

    Dr. Wysocki!

    What an honor!!! Thank you so much for taking the time to learn about my project and being kind enough to leave a comment. As a recipient of the USP Scholarship, it has been an absolute pleasure working with my mentor to put this project together. Thank you so much for the phenomenal opportunity of conducting research in the College of Agriculture as a University Scholar.