Abstract The task of nectar foraging in honey-bees is partitioned between foragers and receivers. Foragers typically transfer a nectar load in the nest as sub-loads to several receivers rather than as a single transfer. Foragers experience delays in finding receivers and use these delays to balance the number of foragers and receivers. A short delay results in the forager-recruiting waggle dance whereas a long delay results in the receiver-recruiting tremble dance. Several nectar transfers increase the cost of this system by introducing additional delays in finding extra receivers. We tested four hypotheses to explain the occurrence of multiple transfer. We found no evidence that multiple transfer is due to different crop capacities of foragers and receivers or that it results from extensive trophallactic interactions with nest-mates. Receiver bees frequently evaporate nectar in their mouthparts to hasten the production of honey. The suggestion has been made that multiple transfer is driven by receivers who take partial loads from foragers to enhance nectar evaporation. An alternative suggestion is that foragers drive multiple transfer to gain better information on the balance of foragers and receivers. Multiple sampling of the delay in finding a receiver reduces the standard deviation of the delay mean and so provides foragers with better informa- tion than is provided by a single delay. The enhanced- evaporation hypothesis predicts that receivers break foragers’ first transfer whereas the information improve- ment hypothesis predicts foragers break their first trans- fers. Furthermore, only the information improvement hypothesis predicts a high level of multiple receptions. Data on transfer break-off and receiver behaviour strongly support the information improvement hypothesis and reject the enhanced-evaporation hypothesis. We suggest that multiple transfer is an adaptive sampling mechanism, which improves foragers’ information on colony work allocation, and that multiple sampling is a common feature of social insect societies. Keywords Honey-bee · Nectar transfer · Receiver · Foraging · Information improvement Introduction Adaptive organisation and integration depend upon information and communication (Detrain et al. 1999). Nowhere is this more pertinent than in the organisation of the activities of the many individuals that comprise an insect society (Seeley 1995). Foraging is one vital area of colony life that uses information to co-ordinate indi- vidual activities. Efficient organisation of foraging normally involves two complementary processes. One is directing foragers to profitable food patches, via mecha- nisms such as tandem running, pheromone trails or the waggle dance of honey-bees (Wilson 1971; Hölldobler and Wilson 1990; Seeley 1995). The second is adjusting the total foraging effort to the colony’s ability to use, process or store food (Seeley 1995; Anderson and Ratnieks 1999). In the honey-bee, for example, nectar collected by foragers is transferred to receiver bees, who then store it in cells. Efficient nectar collection, therefore, requires both the direction of unemployed foragers to good food patches and a balance between the work capacities of nectar foragers and receivers. Waggle dances made by honey-bee foragers function in both processes. The dance directs foragers to profitable food patches and, because the bees recruited were previously unemployed foragers (Seeley 1995), it also functions in balancing the work capacities of foragers and receivers (Anderson and Ratnieks 1999). Clearly, the waggle dance, and more generally whether or not a forager should dance, is at the heart of efficient foraging organisation in the honey-bee (Seeley 1995). As a result, there should be strong selection making the ability of individual foragers to dance or not appropriate to the Communicated by R. Crozier A.G. Hart ( ✉ ) · F.L.W. Ratnieks Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK e-mail: bop98agh@sheffield.ac.uk Tel.: +44-114-2220149, Fax: +44-114-2760159 Behav Ecol Sociobiol (2001) 49:244–250 DOI 10.1007/s002650000306 ORIGINAL ARTICLE Adam G. Hart · Francis L.W. Ratnieks Why do honey-bee (Apis mellifera) foragers transfer nectar to several receivers? Information improvement through multiple sampling in a biological system Received: 7 February 2000 / Revised: 7 August 2000 / Accepted: 25 September 2000 / Published online: 20 December 2000 © Springer-Verlag 2000