The radio-frequency identification (RFID) homing flight ring test aims at developing a method, which can assess sublethal effects of xenobiotic substances on the navigation of foraging bees (RFID ring-test protocol; Fourrier et al. 2018). Thereby, honeybee's (Apis mellifera) biological parameters and corresponding behavioral processes might strongly influence the output of this test-method. Accordingly, previous experiments demonstrated that the homing ability of nectar foragers differed between group- and single-bee-feeding based on uneven crop content of returning bees and/or due to uneven food distribution via trophallaxis. Therefore, we here evaluated if pollen foragers represent a more homogenous test unit, when test item solutions are administered to groups of bees and thus are distributed between each other via trophallaxis, assuming that pollen foragers have more similar (empty) crop contents when returning from foraging flights.
