Cross-activity of honeybee queen pheromones in bumblebees provides evidence for sensory exploitation

The evolutionary origin of queen pheromones, which regulate reproductive division of labor in insect societies, has been explained by two evolutionary scenarios: the sender-precursor hypothesis and the sensory exploitation hypothesis. These scenarios differ in terms of whether the signaling system was built on preadaptations on the part of either the sender queens or the receiver workers. While some social insect queen pheromones – such as cuticular hydrocarbons – were likely derived from ancestral fertility cues and evolved according to the former theory, the honeybee’s queen mandibular pheromone (QMP) has been suggested to act directly on pre-existing gene-regulatory networks linked with reproduction. This is evidenced by the fact that QMP has been shown to also inhibit ovary activation in fruit flies, thereby implying exploitation of conserved physiological pathways. To verify whether QMP has similar effects on more closely related eusocial species, we here tested for QMP cross-activ...