The experiments were conducted with Apis cerana cerana Fabricius under natural conditions. After the start of swarming, workers were sampled randomly both from the mother colony and the swarms, and preserved in 95% alcohol for further DNA analysis. All of the sealed queen cells were transferred into the incubator for emergence and observed every 30 minutes to record the emerging order of virgin queens. Subfamily compositions were subsequently analyzed using three MRJPs. The colonies were composed of 13, 12 and 9 subfamilies, respectively. Most of the super-sister workers of immature queens were selectively chosen to stay in the colony. Subfamily distribution in both the swarms and the workers staying in the colony were significantly different from the control, which indicated that some subfamilies were active in swarming, while the others were less active. Our data from the three MRJPs firstly indicated the presence of nepotism between the workers staying in the colony and the immature queens during the swarming, and the nepotism may stimulate the swarming tendency of other workers.