Effect of queen pheromone on worker bees of different ages: behavioural and electrophysiological responses

Abstract - The attraction responses of differently aged worker bees to queen pheromonal blends were studied in a 4-field airflow olfactometer. The effects of the nature of the queen signal - either the synthetic mixture shown to be behaviorally active by Slessor et al (1988), or a queen-head extract -, and the rearing conditions were investigated. The composition of the queen-head extract with respect to the constituents of the synthetic blend was chemically analyzed, and differences in amounts of components were discussed. Olfactory-based behavioral responses were elicited by both pheromonal signals; the queen-head extract induced higher responses than the synthetic mixture, the youngest bees of < 5 d old being the most responsive. Similar responses were found in queenless caged bees and in bees reared in a hive, suggesting that attraction to the queen was probably not influenced by prior experience, at least when deprivation to the queen signal occurred after emergence. Electroantennogram responses to the queen signals were recorded concurrently. Olfactory sensitivity was higher to the queen-head extract than to the synthetic pheromone, and was not age-dependent for the age groups tested. No correlation between the maturation of antennal responses and the maturation of behavioral responses was found.