REGULATION OF WORKER ACTIVITY IN A PRIMITIVELY EUSOCIAL WASP, ROPALIDIA-MARGINATA

Ropalidia marginata, a tropical, primitively eusocial, polistine wasp, is unusual in that the queen (the sole egg-layer) is neither the most behaviorally dominant nor the most active individual in the colony. T he queen by herself rarely ever initiates interactions toward her nest mates or unloads returning foragers. There are always a few workers i n the colony who are more dominant and active than the queen. Absence of the queen from her colony does not affect colony maintenance activi ties such as foraging or brood care, but it always results in one indi vidual becoming very aggressive and dominant. The dominant worker beco mes the next queen if the original queen does not return. The queen do es not appear to play any significant role in colony activity regulati on. Instead, colony activities appear to be regulated by several mecha nisms including dominance behavior toward foragers, feeding of larvae, and the unloading of returning foragers, all mediated by workers them selves. Regulation of colony maintenance appears to be based on direct evaluation of the needs of the colony by the workers themselves. The queen however has perfect reproductive control over all workers; worke rs never lay eggs in the presence of the queen. It appears therefore t hat the mechanisms involved in regulation of worker activity and worke r reproduction are separate in R. marginata. These findings contrast w ith other primitively eusocial species where the queen acts as a ''cen tral pacemaker'' and controls both worker activity and worker reproduc tion.