Changes in food source profitability affect the trophallactic and dance behavior of forager honeybees (Apis mellifera L.)

Since nectar constitutes a highly variable resource, forager honeybees (Api s mellifera) always adjust their social foraging activities according to th e current profitability of the nectar sources they exploit. If trophallaxis , food exchange among individuals of the same colony, serves to improve the coordination among nectar foragers, as occurs with the dance behavior, a h igh correlation might be expected between the foragers' trophallactic behav ior and the profitability of the food sources they exploited. The aim of th is work was to analyze whether a forager bee changes her trophallactic beha vior with the varying profitability of a food source. In addition, since fo od source profitability affects dance behavior, we also analyzed the degree of coupling between the trophallactic and dance behavior of returning hone ybees. Results show that trophallaxis by forager bees inside the hive chang ed rapidly with fluctuations in food source profitability. After an increas e in profitability, returning foragers (1) increased the number of trophall actic offering contacts, (2) decreased the average duration of offering con tacts, (3) shifted the temporal distribution of offering contacts from bein g mainly near the beginning of the time in the hive to being more evenly di stributed throughout the entire visit, (4) begged for food less frequently, and (5) shifted their begging toward the very end of the visit. Regarding their dance behavior, foragers danced earlier in their visits to the hive a nd performed more waggle runs when the profitability of the food source was increased. Furthermore, the trophallactic and dance behaviors were affecte d not only by the absolute profitability of the food source but also by cha nges in profitability. Taken together, these results indicate that, in addi tion to dance behavior, short trophallactic interactions of returning forag ers (which include both offering and begging contacts) may help foragers to communicate information about rapidly fluctuating resource opportunities.