Unlike mammals, honey bees have no adaptive immune system — no antibodies, no immune memory cells. Instead they rely entirely on a fast, fixed innate immune system combined with colony-level social defences. This cutaway view of the hemolymph (bee "blood") cavity shows the cellular and chemical weapons a bee deploys the moment a pathogen breaches its cuticle.
Because honey bees lack antibody-based immunity, colony-level "social immunity" — hygienic behaviour, grooming, propolis use and gut microbiota — does much of the work that antibodies do in vertebrates, protecting the whole colony rather than just one bee.
A cutaway view inside a honey bee's hemolymph cavity, where free-floating hemocytes hunt down invading bacteria and fungal spores through phagocytosis and encapsulation, antimicrobial peptides diffuse from the fat body, and — if infection wins — nurse bees step in with hygienic removal.
Honey bees have no antibody-based adaptive immunity. Instead they rely on innate cellular defences (hemocytes performing phagocytosis, encapsulation and melanization), chemical defences (antimicrobial peptides from the fat body), and colony-level social immunity (hygienic behaviour).
Raise the pathogen load to overwhelm the defences, or add more hemocytes to fight back. Toggle antimicrobial peptides and hygienic behaviour on and off to see how each layer of defence changes the outcome for the colony.
Because a single bee's innate immune system can be overwhelmed quickly, much of a honey bee colony's real protection comes from social immunity — hygienic behaviour, allogrooming, propolis and a shared gut microbiota — not from any one bee's own bloodstream.