Effect of cold narcosis on foraging behavior of European honey bees (Apis mellifera ligustica) tracked using a radio-frequency identification (RFID) system

Radio-frequency identification (RFID) is both a commonly used method and a promising tool for investigating the foraging activities of bees. To prevent loss of electronic tags from individual bees, they must be immobilized long enough for adhesives to dry, but because narcosis can negatively affect bee health and behaviors, a very brief narcosis period is recommended. The present study assessed the impact of 30 min of cold narcosis, compared with carbon dioxide or no narcosis, on foraging activities using RFID monitoring. From each of three hives, 8 to 10 bees were placed in each of three narcosis treatments (n = 85), then tagged and monitored for homing success, activity after returning to the hive, and duration of flights outside the hive. Bees showed no significant differences in homing success and flight duration between cold narcosis treatment and the control (no narcosis), whereas bees narcotized by carbon dioxide showed significantly lower homing success and shorter flight duration than control bees. We conclude that for observing bee foraging behaviors using RFID systems, the effects of cold narcosis on ice for 30 min on foraging behaviors are acceptable, and cold narcosis is more practical for tagging many bees at once than physical immobilization using plunger cages.