Ethology of Hygienic Behaviour in the Honey Bee Apis mellifera L[ "Hymenoptera] Apidae#] Behavioural Repertoire of Hygienic Bees

Hygienic behaviour performed by middle!aged worker bees is an important intranidal task in colonies of the honey bee Apis mellifera "L[#[ It comprises detecting diseased brood in the larval and pupal stages and removing all such infected brood\ thereby decreasing the incidence of infection[ Hygienic behaviour consists of two task!components] uncapping cells and removing the cell contents[ The aim of this study was to observe bees performing hygienic behaviour to determine their age at performance of the behaviour and to describe their behav! ioural repertoire[ The bees performing hygienic behaviour were middle!aged bees\ younger than foragers[ In the colonies where the behaviours of individual bees were observed\ all bees performing the hygienic behaviour were seen to exhibit both the components\ though at di}erent frequencies[ One behavioural class per! formed the task of uncapping cells at higher frequencies than the task of removing cell contents\ while another class performed both tasks to the same extent[ While these two classes had higher frequencies of the tasks comprising the hygienic behaviour but lower frequencies of other common behaviours in their repertoire\ a third class of bees included those that performed all behaviours in their repertoire at similar frequencies[ There was no di}erence in the ages of the bees in these three behavioural classes[ These results suggest that there is no evidence of task partitioning among bees performing the hygienic behaviour[ The segregation observed could\ however\ be based on their response thresholds to the stimulus and:or on their ability to discriminate the various cues emanating from the dead brood[ Corresponding author] H[ S[ Arathi\ Department of Entomology\ 108 Hod! son Hall 0879 Folwell Ave\ University of Minnesota\ St[ Paul\ MN 44097\ USA[ E!mail] arathiÝtc[umn[edu