Technical Abstract: The influence of the queen on nestmate recognition and the formation of colony odor was studied in Cataglyphis niger using behavioral and biochemical approaches. The absence of the queen did not diminish the aggression of her workers, or change their label. Queens possessed significantly greater amounts of hydrocarbons in the postpharyngeal gland than workers, but the amount on the thoracic epicuticle was equivalent. A study of de novo biosynthesis of the hydrocarbon constituents and their distribution revealed, unexpectedly, that in workers the total amount of hydrocarbons produced was significantly higher than in functional queens. Queens tended to receive more and give less of their postpharyngeal gland content. Transfer to the epicuticle was low and comparable in all encounters. Group encounters in which eight prelabeled workers were put together with one non-labeled nestmate worker and one non-labeled queen revealed that in most cases workers transferred more hydrocarbon to the queen than to the worker. This slight preference for the queen is presumably amplified in a whole colony and can explain the copious postpharyngeal gland contents observed in queens. Both behavioral and biochemical results imply that in mature colonies of C. niger the queen contributes little to the colony odor. We hypothesize that the larger amount of material in the postpharyngeal gland of queens is the result of preferential transfer to the queen, and selection on the queen to maintain an odor close to the average colony odor. Any alienation towards the queen by her workers due to disparate body odors may result in reduced reproductive success.