The Influences of Queen Mandibular Pheromone and Brood Pheromones on the Process of Queen Rearing in Colonies of Honey Bees

The Influences of Queen Mandibular Pheromone and Brood Pheromones on the Process of Queen Rearing in colonies of Honey Bees (Apis meliferra spp.)

Highly social colonies of honeybees (Apis mellifera spp.) communicate through the use of chemical pheromones to regulate colony behaviour (Winston et al., 1991). One task driven by pheromones is queen rearing, which occurs when a behavioural tendency of workers to rear queens is not suppressed and the production of queen cells along the comb begins (). These queen cell eggs receive fertilized eggs at which time the workers provide specialized feeding of royal jelly to induce the proper development of the female egg into a queen (). The process of queen rearing can occur in response to pheromone cues indicating preparation for colony reproduction through swarming, a failing queen needing to be replaced through supersedure, or the loss of a queen resulting in emergency queen rearing. Although it is understood that pheromone communication is an important factor in queen rearing regulation, it is crucial to answer the question regarding what particular pheromones are responsible for the stimulation or inhibition of queen rearing?

A crucial pheromone required for the regulation of queen rearing is queen mandibular pheromone (QMP) that acts to suppress worker behaviour, while subsequently displaying stimulating effects under certain conditions. This pheromone is produced in a queen’s mandibular glands and secreted as a signal of her presence (Winston et al., 1990). QMP inhibits the process of queen rearing by suppressing aspects of worker bee behaviour related to queen cell production in honeybee colonies (Winston et al., 1990,1991; Pettis et al., 1995). These stimulatory and inhibitory aspects of QMP were demonstrated by Winston et al. 1990 under queenless colony situations as the researchers investigated the extent of QMP’s inhibitory effects on colony behaviour through the addition of different QMP dosages to a colony and analyzing the behavioural changes of workers in response to the synthetic additives. The results proved relatively consistent, as high dosages of synthetic material were effective in the suppression of queen rearing for several days in a colony of 8,000-10,000 worker bees. Additionally, the treatment groups in the experiment receiving either no pheromone or significantly lower dosages of QMP were seen to initiate queen rearing much sooner than the high dosage treatments demonstrating the stimulatory effects of QMP. Adversely, after 10 days all colonies were observed to rear queens as the effects of QMP became diminished over time regardless of the QMP dosage received indicating that QMP is unable to fully inhibit the worker tendency to begin queen cell production. Winston et al. 1991 further examined how these dosage dependent behaviours are influenced by the amount of QMP perceived by congested and uncongested colonies, thus stimulating or inhibiting queen rearing. The researchers determined that as the amount of QMP reaching workers is diminished in congested colonies, queen rearing worker behaviour is stimulated by a reduction of the pheromone’s chemical inhibition properties.  Although, when a congested colony was sprayed synthetic QMP using aerosol sprays, effective transmission of QMP was accomplished and a delay in queen rearing was observed. Therefore, pheromonal efficacy of QMP is partially responsible for these stimulatory and inhibitory aspects of QMP seen in a colony setting, but cannot be held fully accountable for the complete suppression of queen cell production (Winston et al., 1991; Pettis et al., 1995).