Immune response variation among different honey bee genotypes

Honey bees (Apis mellifera) are important insects for pollination of over 130 fruits, vegetables, and other crops all over the United States, equating to a worth of $15 billion dollars (USDA). From pollination, honey bees can pick up the fungus Nosema ceranae, which can cause diarrhea, lethargy, and death in honey bee colonies. It is unknown how the use of heat-killed spores changes the immune response to Nosema ceranae amongst different honey bee genotypes, such as commercial managed bees and feral survivor bees. In this study, these two genotypes were given different treatments, including sugar water, dead spores, and live spores to determine the immune response. The bees were analyzed for survival, dissected, and had hemolymph extracted after 6, 12, and 15 days post-infection to analyze the spore intensity, and look at the changing titers of juvenile hormone, vitellogenin, and chitinase in the hemolymph. Following these assays, we found that survivor honey bees had decreased survivability when compared to managed honey bees. However, the spore intensities in managed bees were higher than those in survivor bees, suggesting that defending against the spores can take a toll on survivor bees’ immunity, compared to managed bees who have encountered this parasite before.