Decision making in honeybees: Evaluation of risk taking and benefits in colony defense

Selection pressure acts simultaneously at several levels – including at the individual level and the colony level – to minimize risks while maximizing fitness. In honeybees, defense against large predators is risky and costly, and the ultimate reward for an individual successfully defending the colony is death from loss of the stinger into the potential predator. The benefit of successfully stinging a threatening predator is reduction in the probability of damage to, or destruction of, the reproductive unit: in this case, the honeybee colony of 2-50 thousand individuals. Defensive failure can have the ultimate cost to both the individual and the colony resulting in the failure to pass their genes to subsequent generations (fitness=0). Given the extreme risks and costs of defensive behavior on one hand, and the potential benefit to individual and colony fitness on the other hand, individual defenders should optimally evaluate the risk-benefit ratio in executing defensive actions. I hypothesize that risk of predation to a colony is proportional to the colony resources as measured by immatures, honey and pollen reserves, and stability of the nest cavity, and that defending workers will be able to evaluate the risk to the colony and will tailor their defensive vigor accordingly. Data testing defensive responses of workers in colonies with little to lose and in others with much to lose support the hypothesis and will be discussed.