Honeybees

Several C10 acids are important in honeybees. (2£)-9-Oxodecenoic acid is the sex attractant of the virgin queen. After mating the fertile queen produces a mixture of this and four other substances (Figure 3.32), each weakly active alone, as components of the 'queen substance' which prevents queen cell construction by workers and a number of other actions which signal the presence of a dominant reproductive queen. Both enantiomers of 9-hydroxydecenoic acid have to be present for highest activity, a rare example of synergism between enantiomers in insect semiochemicals. The workers make (2£)-10-hydroxydec-2-enoic acid (known as royal jelly acid, because it is part of the food given to queen larvae) and (2J£)-9-carboxynon-2-enoic acid. Both 9-hydroxy- and 10-hydroxy-compounds are made preferentially from stearic acid. The stearic acid is oxidized at the 17- or 18-position, and then the chain shortened from the carboxyl end by loss of four acetate units by (3-oxidation (Figure 3.33). This can be done by both queens and workers, so presumably, the 17-oxidation route operates in the queen preferentially and the 18-oxidation route in the workers. The actions are catalyzed by P450 oxidases.

Figure 3.32 The substances that make up the queen substance of Apis mellifera. The quantity given under each structure is the amount found in a single queen bee

Figure 3.32 The substances that make up the queen substance of Apis mellifera. The quantity given under each structure is the amount found in a single queen bee

\ part of "queen substance"

"royal jelly acid"

Figure 3.33 The formation of bee substances from stearic acid. Both queens and workers are capable of using both pathways but those shown actually operate preferentially. 9-Hydroxydec-2-enoic acid is also used by the queen when swarming to hold the workers in the swarm

\ part of "queen substance"

"royal jelly acid"

Figure 3.33 The formation of bee substances from stearic acid. Both queens and workers are capable of using both pathways but those shown actually operate preferentially. 9-Hydroxydec-2-enoic acid is also used by the queen when swarming to hold the workers in the swarm

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