A DISEASE OF HONEY BEE CAUSING BEHAVIORAL CHANGES AND MORTALITY

A disease of Apis mellifera adults was observed to cause abnormal behavior and mortality. Tests conducted on colonies isolated in observation hives and in flight cages showed that diseased bees were often attacked by other bees in the colony and, as a result of the attacking, diseased bees became black and hairless. The attacking bees themselves became infected, hence, the disease was transmitted through the colony. Occasionally diseased bees were not attacked but withdrew from the main cluster and died. Bacteria-free suspensions prepared from diseased bees were infectious when injected into healthy bees and a number of viruslike particles were found in these suspensions. The effect of the disease on the welfare of the colony was followed by the experimental introduction of diseased bees into healthy normal colonies. © 1969.