Abstract: 【Aim】Bumblebees, as social insects, have divisions of labor in different castes and even different physiological stages of the same caste. Flight ability is one of the key factors affecting their multiple behaviors including foraging and copulation, at different physiological stages. This study aims to explore the influences of division of labor and body weight on the flight ability of Bombus terrestris, so as to provide a theoretical basis for the efficient production and utilization of B. terrestris.  【Methods】The flight ability of B. terrestris involving flight distance, flight velocity, and flight duration within 24 h, was measured by a flight mill on three castes (queens, workers and drones), and queens at different physiological stages (i.e. virgin queens, post-diapause queens and egg-laying queens), and the correlations between the flight ability and the caste, body weight and post-flight body weight loss were analyzed.【Results】The cumulative flight distance, cumulative flight duration, maximum flight distance and maximum fight duration of drones of B. terrestris were significantly longer than those of workers and queens within 24-h tethered flight. The average flight velocity and maximum flight velocity of drones and queens were significantly higher than those of workers, i.e. the flight ability of workers was the worst under the same conditions. There were significant differences in the flight ability of queens at different physiological stages. The cumulative flight distance, cumulative flight duration, maximum flight distance, maximum fight duration, average flight velocity and maximum flight velocity of the virgin queens were significantly higher than those of the post-diapause and egg-laying queens. There was no significant difference in the flight distance and flight velocity between the latter two queens. The cumulative flight distance and duration of queens and workers were significantly positively correlated with the body weight, but there was no significant correlation between their average flight velocity and body weight. In addition, no significant correlation was observed between the flight ability of drones and their body weight, but the cumulative flight distance and duration of drones were significantly positively correlated with the postflight body weight loss. The cumulative flight distance and duration of virgin queens were positively correlated with the body weight, while the cumulative flight distance and duration of post-diapause and egg-laying queens were positively correlated with their post-flight body weight loss.【Conclusion】The difference in the flight ability of B. terrestris is closely related to the changes in staged functions, and the flight abilities of B. terrestris at different castes and physiological stages are somewhat correlated with their body weight and post-flight body weight loss, respectively. These results may provide the theoretical basis for optimizing the breeding of B. terrestris in production applications.

Key words: Bombus terrestris; flight ability, body weight, caste structure, division of labor