Interaction between Immune and Nervous Systems in Insects

In vertebrates, it has been established that interactions exist between the immune system, the nervous system, and behavior. A comparative examination of these interactions in other animals helps us understand the evolution of this interaction. It may also be possible to develop animal models of important human pathologies, which are due to the interactions between these two systems. In insects an immune-behavioral interactions similar to those seen in vertebrates has been shown to exist. This suggests that this interaction has a highly conserved function. For example, activation of immune response produces illness-induced anorexia, behavioral fever, changes in reproductive behavior, and decreased learning ability in different species. This thesis establishes further examples of this interaction between the immune and nervous system, examines the physiological basis between them and explores the evolutionary dynamics of the interaction. I establish this interaction between the immunity and memory in bumblebees in a free flying paradigm, where previously it had only been shown in artificial classical conditioning assays. Then, I checked the immunity of different bumblebee colonies of known learning ability to identify any evolutionary relationship between these two traits. I used Drosophila melanogaster to study the sleep phenomenon after activation of the immune system as a potential intermediary between immunity and memory. Finally, I checked the olfactory learning of Drosophila melanogaster after activating their immune system to see if the fruit fly would make a useful model for immune modulated memory reduction.