Individual recruitment in honeybees Apis mellifera L: the dependence of the rate of bees arriving at the feeding place on food source profitability

FERNÁNDEZ, PATRICIA; FARINA, WALTER M

ACTA ETHOLOGICA

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2002 vol. 4 p. 103 - 108

0873-9749

The recruitment of honeybee foragers individually exploiting a low-flow rate-feeder that presented different temporal reward programs was experimentally analyzed. By capturing hive bees that landed at the feeder in a 2-h period, the arrival rate of incoming bees could be obtained. With this procedure we quantitatively analyzed the maximum number of hive bees that can be brought to the feeding station by single foragers. Test bees collected sucrose solution during 12 visits to a ratefeeder located 160 m from the hive. The constant programs offered 0.6, 1.2, or 2.4 M sugar for all 12 visits, while the variable programs delivered either 0.6, 1.2, or 0.6 M or 0.6, 2.4, or 0.6 M, with four visits for each molarity. Results showed that the sucrose concentration exploited by single foragers increased the arrival rate. Moreover, there was a linear relationship within this range of sucrose concentrations that presented a slope of 1.58. Since the sugar solutions were provided at the same flow rate (5 μl/min) in all the programs, the arrival rate expressed in terms of sucrose flow rate (milligrams of sucrose/minute) shows that one additional incoming bee per hour arrived when the single forager assessed an increase in the sucrose flow rate of 0.75 mg sucrose/min at the rate-feeder. The absence of differences in the frequency of visits of the single foragers during the constant programs suggests that the differences observed in the arrival rate can mainly be explained by a more intensive display of the recruitment mechanisms performed per foraging trip instead of by their iterativeness throughout different foraging cycles. Variable reward programs showed that arrival rate is rapidly adjusted according to the reward change and is independent of its magnitude.