1Department of Zoology, George S. Wise Faculty of Life science, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel.
2Institute fur Organisch Chemie, Universitate Hamburg, Hamburg, Germany.
Honey bee Dufour's gland secretion is caste specific. Queen, but not worker glands are
fortified with long chain esters. This difference may be linked to reproduction since egg-laying
queenless workers posses some of the queen characteristic esters (Katzav Gozansky et
al., 1997). To elucidate the biological function of Dufour's gland we tested two
alternative hypotheses:
-Queens mark the eggs with the secretion helping workers to discriminate between
queen-laid and worker-laid eggs (worker policing).
-Dufour's gland secretion constitutes a component of the queen signal bouquet and induces
retinue behavior.
Worker policing experiments revealed that QR workers readily discriminate between
queen-laid and worker-laid eggs. Egg policing was especially effective when workers were
exposed simultaneously, to queen-laid eggs and worker-laid eggs. Neither queens Dufour's
gland secretion nor its synthetic ester constituents prevented egg policing, refuting the
hypothesis that the secretion serves as an egg marking pheromone. When the glandular
secretion is applied either to a glass slide or to another worker, a retinue around the
"surrogate queen" was formed. This effect could be observed also with a synthetic
mixture of the queen esters, albeit higher concentrations were needed. We conclude that
Dufour's gland secretion constitute part of a complex queen signal that is the basis of the
social integrity of the honey bee colony.