Honeybees Dufour's gland - idiosyncrasy of a new queen signal

Abstract

Dufour's gland (DG) secretion of queens in Apis mellifera is normally caste specific. In queenright (QR) workers it is composed of odd n alkanes, while in queens it also possesses long chain esters. However, glandular expression is plastic since queenless (QL) workers produce a queen-like secretion. More- over, QR gland incubated in vitro produced these esters, indicating that glandular activity is regulated. We tested the hypothesis that the secretion is an egg marking pheromone. Chemical analysis of the egg coating re- vealed minute amounts of the queen esters, but neither queen secretion nor the synthetic esters were able to protect worker-laid eggs from policing, refuting the hypothesis. Analysis of abdominal tips further revealed that Dufour's egg secretion is also smeared on the abodominal cuticle, suggesting that its presence on egg sur- face may be due to passive contamination. Next, we tested the hypothesis that the secretion serves as a queen signal. Indeed queens, but not worker glandular secretion were attractive to workers. Dufour's gland / honeybee, queen-signal / caste-specificity / retinue behavior