Mentor: Kathleen Killian, Ph.D.

All organisms rely on the immune system to protect them against disease. Unlike mammals, insects lack acquired immunity and rely solely on the innate immune system, which consists of cellular and chemical defenses (Zdybicka-Barabas et al., 2025). In insects, cellular immunity includes phagocytic cells called hemocytes which circulate in the hemolymph (blood), while chemical defenses include antimicrobial proteins. Hemocytes also produce a critical immune enzyme called phenoloxidase (PO) which produces melanin that coats and kills pathogens (Marieshwari et al., 2023). Additionally, Nitric Oxide (NO), a gaseous immune effector molecule produced by the enzyme Nitric Oxide Synthase (NOS), is produced in response to microbial infection.
Our lab uses the cricket Acheta domesticus to study how the immune system can influence nervous system function and animal behavior. Most insects possess multiple PO genes (as many as 10 in the mosquito), and it has been suggested that the function of these genes may not be limited to immunity (Lu et al., 2014). NO has been found to play a role in regulating social behaviors such as aggression in insects (Stevenson & Rillich, 2016). However, the role of PO in insect behavior is not understood. Our aim in this project was to characterize the effects of PO and NO levels on insect aggressive behavior. Acheta domesticus aggressive behavior is easily characterized, making crickets our ideal model organism.

Explore the Project