Reproductive conflict in the honey bee

Dufour’s gland secretion may allow workerhoneybees to discriminate between queen-laid and work-er-laid eggs. To investigate this, we combined thechemical analysis of individually treated eggs with anegg removal bioassay. We partitioned queen Dufour’sgland into hydrocarbon and ester fractions. The bioassayshowed that worker-laid eggs treated with either wholegland extract, ester fraction or synthetic gland esters wereremoved more slowly than untreated worker-laid eggs.However, the effect only lasted up to 20 h. Worker-laideggs treated with the hydrocarbon fraction were removedat the same rate as untreated eggs. The amount of esterwhich reduced the egg removal rate was far higher thanthat naturally found on queen-laid or worker-laid eggs,and at natural ester levels no effect was found. Our resultsindicate that esters or hydrocarbons probably do notfunction as the signal by which eggs can be discriminated.