Honey bees assess changes in nectar flow within a single foraging bout.

WAINSELBOIM, ALEJANDRO; ROCES, FLAVIO; FARINA WALTER M.

ANIMAL BEHAVIOUR

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2002 vol. 63 p. 1 - 6

0003-3472

Forager honeybees returning to the hive after a successful foraging trip unload the collected liquid to recipient hivemates through mouth-to-mouth food exchange contacts (trophallaxis). The speed at which the liquid is transferred (unloading rate) from donor to recipient is related to the profitability offered by the recently visited food source. Two of the main characteristics that define food source profitability are the flow of solution delivered by the feeder and the time invested by the forager feeding at the source (feeding time). To investigate which of these two variables is related to unloading rate, we individually trained donor foragers to a regulated-flow feeder that presented changes in the delivered flow of solution within a single foraging bout, while feeding time remained constant. With the range of flows used, bees attained maximum crop loads in all experiments. During the subsequent trophallactic encounter with an unfed recipient hivemate, unloading rate was differentially affected by the changes in flow of solution presented during the previous foraging trip at the source, depending on whether there had been an increase or a decrease of flow rate within that visit. Foragers unloaded at lower rates when they experienced a decrease in flow rate, but did not increase the unloading rate when presented with an increase at the food source. Thus, forager honeybees seem to be able to detect variations in the delivered flow of solution, since they modulate unloading rate in relation to these changes, although decreases in food value seem to be perceptually weighted in relation to increases, independently of the time invested in the food-gathering process.