Sticking to their choice - honey bee subfamilies abandon declining food sources at a slow but uniform rate

1. The allocation of honey bee foragers among food patches is a result of decisions made by individual bees that are based on internal and external cues. 2. Decision-making processes are often based on internal thresholds. For example, if the quality of the food source is assessed by a forager as exceeding its internal threshold, the bee will continue foraging on that food source. 3. It is often assumed that all individuals have the same threshold and therefore use the same thresholds in decision-making, but because the honey bee queen mates with 12-30 males, the workers within a colony are genetically heterogeneous. Thus, the thresholds used by individual bees may be genetically variable within a colony. 4. Models of colony-level foraging behaviour of honey bees suggest that the rate of abandoning food sources is a critical parameter affecting foraging success. Moreover, these models show that variance among subfamilies in their abandonment rates may increase the colony's foraging efficiency. 5. Experimental data showing the relationship between the probability of abandoning a food source and its profitability are lacking, as is information on any variation in abandonment rates among subfamilies. 6. Abandonment rates were determined experimentally for four honey bee families for seven different sucrose concentrations. The results showed that abandonment rates appear to be invariant among (sub)families. The importance of forager fidelity to declining food sources is discussed with respect to foraging efficiency in a changing environment.