When a colony becomes queenless and without the possibility of requeening, honeybee workers initiate reproduction and lay male eggs about a week later. Assays in which two bees were confined in a small arena revealed that they establish a reproductive dominance hierarchy, i.e., one worker demonstrates greater ovarian development than her paired bee. Reproductive dominance is independent of relatedness, and can be established between full sisters, cousins, or random nestmates. A social environment, however, is obligatory, as singly housed bees fail to develop ovaries on the same time scale. Allowing varying degrees of social interactions between the paired bees revealed that olfaction of volatile bee compounds, as well as tactile communication, seem to provide the necessary social environment. Ovarian development was accompanied by the production of queen-like Dufour's gland secretion in these workers. Especially notable was the increase in the queen-like esters. This increase was tightly linked to ovarian development and not necessarily to the dominance status of the bees in the pair. Thus, the occurrence of queen-like esters can serve as a reliable fertility signal. Advertising ovarian status may recruit helper workers with less developed ovaries (and which are less likely to successfully reproduce before colony breakdown) to assist their nestmates and thereby gain inclusive fitness. Revealing the role of Dufour's gland secretion as a fertility signal adds another dimension to our understanding of how queen pheromones operate. The mandibular-gland secretion is a good predictor of dominance hierarchy, being correlated with false-queen characteristics but not fertility, whereas Dufour's gland secretion is a good predictor of fertility but not dominance hierarchy.
|Number of pages||7|
|Journal||Behavioral Ecology and Sociobiology|
|State||Published - Jul 2005|
Bibliographical noteFunding Information:
Acknowledgements This research was supported by the Israel Science Foundation founded by the Israel Academy of Sciences and Humanities. The authors wish to thank two anonymous reviewers for their helpful comments. We thank Tovit Simon for her technical help, Armin Ionescu for his statistical assistance, Josef Kamer and Haim Efrat from Tzrifin Apiary for assistance in establishing experimental hives, and N. Paz for editorial assistance.
- Dufour's gland
- Fertility signal
- Reproductive dominance