Social Immunity and the Superorganism: Behavioral Defenses Protecting Honey Bee Colonies from Pathogens and Parasites

Understanding the complexities of social insect immunity, that is, how insects combat pathogens, parasites and pests, is a fundamental question that not only has broad applications for understanding disease dynamics in social groups (Fefferman thus individuals in that colony survive to successfully spread their genetics through subsequent generations via the production of drones, swarms, and queens. In many ways, immunity in social insects exemplifies the superorganism concept, whereby there is an immune system in individual bees, but there is also a colony-level immune system. Both function to promote survival not only of an individual bee but also of the colony. Given the reduction in immune genes that has now been noted for honey bees and Hymenoptera in general (Barribeau et al., 2015; Evans et al., 2006; Gadau et al., 2012; Simola et al., 2013), it seems as though the evolution of numerous colony-level, largely behavioral mechanisms has occurred either to compensate for the reduced investment in physiological immunity or as a result of the reliance on colony-level defenses relaxing the selection pressure for a stronger individual immune defense (Harpur & Zayed, 2013).