Dealation activates the helper phenotype in a primitively-eusocial ant gyne

One of the major evolutionary transitions is the shift from solitary to eusocial life which is further followed by the evolution of morphologically-distinct castes of reproducers and helpers in many highly-eusocial insect species. Since a dispersal polyphenism, where some individuals develop wings while others do not, appears in some highly-social insects like termites, but not in others like honey bees, the role of dispersal polyphenisms in the evolution of eusociality in ants is unclear. By comparing  ant gynes from a species with a weak queen-worker dimorphism under alate and dealate conditions, we found that the loss of wings initiates the helper-like phenotype characteristic of ant workers. Not only do gynes show wing-dependent differences in chemical signaling, but dealate gynes also display helper-like reproductive hierarchy-forming behaviors which do not occur during colony foundation. Since gynes can activate the helper phenotype after wing loss, the essential difference between ant queen and worker castes is a dispersal polyphenism. Individuals with lower dispersal capacity might have benefited from helping in the colony, providing an early step in the evolution of ant eusociality.