Sound responses of honey bees to six chemical stimuli

Sound responses by caged 1-, 2- and 3-week-old worker honey bees (Apis mellifera) to two bee alarm substances (isoamyl acetate and 2-heptanone), two components of the Nasonov gland pheromone (citral and geraniol), and two odoriferous compounds (methyl benzoate and frans-cinnamaldehyde), were recorded and analysed. The mean frequency of worker bee sound responses to the alarm substances was easily differentiated statistically from all the others. The adaptive significance of the differential sound response to alarm substances remains unclear. As one-week-old bees did not respond to isoamyl acetate and 2-heptanone as quickly as the older bees, it is suggested that for the first week of life, with respect to acoustic responses, these compounds do not function as alarm substances.