The Scent of the Waggle Dance

Abstract

The waggle dance of honey bee (Apis mellifera L.) foragers communicates to nest mates the location of a profitable food source. We used solid-phase microextraction and gas chromatography coupled with mass spectrometry to show that waggle-dancing bees produce and release two alkanes, tricosane and pentacosane, and two alkenes, Z-(9)-tricosene and Z-(9)-pentacosene, onto their abdomens and into the air. Nondancing foragers returning from the same food source produce these substances in only minute quantities. Injection of the scent significantly affects worker behavior by increasing the number of bees that exit the hive. The results of this study suggest that these compounds are semiochemicals involved in worker recruitment. By showing that honey bee waggle dancers produce and release behaviorally active chemicals, this study reveals a new dimension in the organization of honey bee foraging. A honey bee colony consists of many thousands of individuals, all of which help to perform the work that allows their colony to thrive. To coordinate their efforts, honey bees have evolved a complex communication system, no part of which is more sophisticated than the waggle dance. The waggle dance is unique, because it exhibits several properties of true language, through which a forager communicates the location and profitability of a food source to other bees in the darkness of the hive. The information coded in the dance has been extensively researched, but we still do not understand how information is actually transferred from the dancing bee to the receivers of the message. Because information is often transferred by scent in honey bee colonies, we investigated whether waggle dancers produce a scent that distinguishes them from foragers that do not dance. We found that dancers produce four hydrocarbons that distinguish them from nondancing foragers, and that, when blown into the hive, increase foraging activity. These results show that waggle-dancing bees produce a unique scent that affects the behavior of their fellow foragers. We discuss likely meanings of this olfactory message and its potential role in waggle-dance communication.