Alexandra Struble

Previous research has shown that immune challenges early in life can have important consequences in long-term immune function. Monarch butterflies are a unique system due to their natural plasticity in aging and the two different generations: summer and fall. This project aims to understand how an early immune challenge impacts immunity and aging in both the summer and fall forms of monarch butterflies. We raised butterflies under summer or fall conditions in climate chambers. Half the individuals were injected with an immune challenge of a lipopolysaccharide (LPS) solution on the day they emerged while the other half were left as uninjected controls. On day 7 and day 21 post-emergence, we did immune measures. Hemolymph was taken from both groups of individuals and the general immune capacity was measured through two measures of immune capacity for all four treatment groups. While this project remains on-going, initial data shows that the butterflies raised in summer conditions had more hemocytes than those raised in fall conditions, regardless of the immune challenge. Interestingly, the immune response was also more variable for butterflies raised in summer conditions compared to fall. We found no significant differences between the 7 and 21 day timepoints. We are still analyzing other aspects of the immune response and lifespan for our experimental individuals. This project will provide new insight into how plasticity in aging shapes investment in immunity.