The Isolation and Synthesis of Queen Substance, 9-oxodec-trans-2-enoic Acid, a Honeybee Pheromone

A method is described for isolating 'queen substance', which is produced in the mandibular glands of queen honeybees and inhibits queen rearing by worker honeybees and development of their ovaries. Queen substance has been identified as 9-oxodec-trans-2-enoic acid and its identity confirmed by synthesis. The synthetic and natural materials have the same biological activity. The methyl ester of 9-oxodecenoic acid is also active. Neither the natural nor the synthetic material completely inhibits queen rearing, whereas the presence of a live queen does. The other inhibitory factor is 'queen scent', which also on its own does not completely inhibit queen rearing. Queen scent plus 9-oxodecenoic acid cause complete inhibition. 9-Oxodecenoic acid did not affect the reproduction of any of the small mammals on which it was tested; nor did it have any pharmacological activity in a wide range of tests.