Age-Dependent Labor Division and Behavioral Characteristics in Vespa velutina nigrithorax (Hymenoptera: Vespidae) Under Laboratory Conditions

Eusocial insects maintain their colonies through diverse cooperative tasks, yet patterns among these behaviors remain poorly understood in hornets. To examine temporal polyethism, we observed a Vespa velutina nigrithorax colony under controlled laboratory conditions (26 °C, 60% RH). Workers were categorized into 5-day cohorts and monitored across five tasks: nest hygiene, prey foraging and first pellet handling, second pellet handling, brood feeding, and foraging for nest materials. Adult emergence occurred in three synchronized cohorts. Workers began to transition to tasks outside of the nest after 6.3 ± 0.9 days. Younger workers performed hygiene and second pellet processing, mid-aged hornets specialized in prey foraging and first pellet formation, while older workers increasingly foraged for nest materials. Brood feeding was observed by hornets of all ages. Cooperative second pellet processing reduced handling duration by workers compared with first pellets. Of the five potential nest materials deliberately provided, adults most frequently collected hornet nest envelopes and tree bark. Multiple correspondence analysis and clustering confirmed distinct but overlapping task profiles, indicating flexibility instead of a fixed sequence. These findings quantitatively demonstrate age-related division of labor in V. velutina similar to that of other social wasps, highlighting behavioral flexibility and cooperative strategies that likely enhance colony efficiency.