Differences in non-stinging aggressive responses of worker honeybees to diseased and healthy bees in May and July

Data from previous studies by the authors were re-examined and compared with previously unpublished results. Responses of groups of 30 caged worker honeybees (Apis mellifera) to introduced hivemates, intruder bees (healthy non-hivemates) and bees afflicted with chronic bee paralysis were monitored in late May and late July at c. 24·4°C. Bees with paralysis elicited the greatest response in both May and July. Responses to hivemates and intruders were similar in May, whereas in July intruders elicited a greater response than hivemates. Average temperature and barometic pressure in the apiary from which test bees were taken were similar during the two observation periods. Relativity humidity (RR) averaged 42% in May and 71% in July, but responses of caged bees maintained experimentally at RH values of 48% and 90% were not significantly different. Changes in the weight of a scale-hive in the same apiary indicated that the change in responsiveness to intruder bees occurred as a nectar flow waned and a dearth period began.