We used six colonies of F. varia, divided into three pairs, in which the first colony in each pair acted as donor and the second colony in each pair acted as receiver. For each experimental session, we removed one old worker from each donor colony and introduced it into the experimental box of the receiver colony.We then observed workers’ responses to the introduced bee. This was repeated with nine different workers from each nest. All 18 individuals of each pair were tested in a single day, with further pairs being tested on subsequent days. After this first session, colony entrances were closed to prevent orkers from foraging. All food stored in the colony was removed and all colonies were fed the same artificial diet. The diet consisted of aqueous sugar solution (25% w/w) and fermented honeybee pollen ad libitum. The cognition sessions were repeated once per week for 4 consecutive weeks. Thereafter the colonies were reopened to the environment, allowing workers freedom to forage. After 2 months, we repeated the manipulation. In the second period of experiments, the colonies that had acted as donor in the first experiments became receivers and vice versa.