Yellowjackets use nest-based cues to differentially exploit higher-quality resources

While foraging, social insects encounter a dynamic array of food resources of varying quality and profitability. Because food acquisition influences colony growth and fitness, natural selection can be expected to favor colonies that allocate their overall foraging effort so as to maximize their intake of high-quality nutrients. Social wasps lack recruitment communication, but previous studies of vespine wasps have shown that olfactory cues influence foraging decisions. Odors associated with food brought into the nest by successful foragers prompt naive foragers to leave the nest and search for the source of those odors. Left unanswered, however, is the question of whether naive foragers take food quality into account in making their decisions about whether or not to search. In this study, two different concentrations of sucrose solutions, scented differently, were inserted directly into each of three Vespula germanica nests. At a feeder away from the nest, arriving foragers were given a choice between two 1.5 M sucrose solutions with the same scents as those in the nest. We show that wasps chose higher-quality resources in the field using information in the form of intranidal food-associated odor cues. By this simple mechanism, the colony can bias the allocation of its foraging effort toward higher-quality resources in the environment.