Effect of high-frequency radiations on survival of the honeybee (Apis mellifera L.)

Recent studies succeeded in developing a method to automatically record honeybees going in and out of the hive. Honeybees were individualized with radio frequency identification (RFID) tags glued onto their dorsal surface and detected at the hive entrance by readers emitting high-frequency (HF) radio waves. In this work we search for a possible adverse effect of HF on honeybees’ survival. Eight-day-old honeybees were exposed to HF (13.56 MHz) or ultra-high-frequency (UHF, 868 MHz) radio waves for 2 h split into ON and OFF periods. The ON/OFF ratio was 1:3 (OFF duration 3, 90, 180, 370 and 360 s) or 1:5 (OFF duration 300 s). Dead individuals were counted every day, and the cumulative mortality rates of exposed and non-exposed honeybees were compared 7 days after exposure. Out of the five experimental conditions, we observed an increase in mortality in two conditions, once after HF and once after UHF exposure, with OFF duration of 5 min or more. We then recommend limiting exposure of honeybees to radio waves to less than 2 h per day, and we conclude that the RFID parameters, like those we used in the field for monitoring hive activity, present no adverse effects for honeybees.