Learning in Vespula germanica social wasps: situations of unpredictable food locations

Vespula germanica is a social wasp that frequently forages on carrion, making several trips between un-depleted resources and the nest. In the present study, we analyze this food relocation behavior, evaluating V. germanica response in situations of successive changes in food location. To this end, we allowed individual wasps to feed five consecutive times from a dish located within an array of landmarks. After each return, the feeder was randomly displaced 60 cm from the previous location, so that when the wasp retuned to the array it encountered a different scenario. We found that on their first return to the new situation, wasps first went to the previously learned location and took some time to find the displaced feeder. Interestingly, during the following returns, wasps discovered the novel food location more rapidly, even though its location randomly changed at each return. Thus, after the first experience of food absence, wasps seem to have learned that food would not necessarily be present at the previous site. Free-flying wasps use past experience of food position change to reduce searching time at previously learned locations. These findings illustrate wasp behavioral plasticity in uncertain foraging contexts.