Therefore, we considered that the Acks signals
detected at each sampling time mainly reflect neural activity involved in the following
phases of the bee ball formation; 0 min: normal
phase before presentation of the hornet; 30 min:
early phase of bee ball formation, such as the recognition of the hornet and / or formation of the bee ball; 60 min: late
phase of the bee ball formation, such as the maintenance of the bee ball.