Behaviour Associated with Hairless-Black Syndrome of Adult Honeybees

Summary

Patterns of adult honeybee behaviour associated with the disease named hairless-black syndrome are described. Bees that were apparently healthy vigorously chewed with their mandibles at the bodies of diseased bees inside the hive and at the hive entrance, thus rendering them hairless and shiny-black in appearance. Individually marked bees engaging in these chewing attacks sometimes licked the thorax of diseased trembling bees. Bees subjected to chewing attacks usually remained passive, sometimes offering food or stroking their probocis, and rarely tried to escape. Attacking behaviour apparently occupied some bees fully for a part of their lives. The level of attacking behaviour in observation hives was cyclic, with a peak every 4–12 days, and a daily peak between 12.00 h and 16.00 h. The behaviour patterns of attacking and attacked bees differed from those of cleaning and cleaned bees. Attacking behaviour was also unlike that of guard bees attacking robbers; however, it was similar in nearly every detail to that of guard bees attacking submissive intruders, and to that of bees attacking workers with developed ovaries in queenless colonies.