Do Melipona bicolor (Apidae, Meliponinae) workers distinguish relatedness among different physogastric queens?

The prediction that the polygynous stingless bee Melipona bicolor workers s hould distinguish physogastric queens to whom they have different degrees o f relatedness was tested. One colony with two physogastric queens was monit ored for 5 consecutive days for the occurrence of the provision and oviposi tion processes (POP) of individually marked workers. We recorded cell provi sioning, egg laying, and cell sealing. The presence of one or both of the q ueens during each POP was recorded. After that, one of the queens from the colony used in the first experiment was removed from the colony and substit uted by two other non-related physogastric queens, from other colonies. In both cases preferences by workers towards their mother or aunt or to the un related queens were not detected. In a third experiment we demonstrated tha t guard bees at entrance of a colony do not reject a physogastric foreign q ueen. Evolutionary and husbandry implications are discussed. (C) Inra/DIB/A GIB/Elsevier, Paris.