Identification of the Tandem running pheromone in Diacamma sp. from Japan (Hymenoptera, Formicidae)

Abstract

The Japanese queenless ponerine ant Diacamma sp. from Japan employs tandem running during nest relocation, in which a leader ant guides nestmate followers one at a time. We replicated this process by presenting one entire abdominal part of a leader, except for the petiole to followers. When the abdominal part had been rinsed with K-hexane, however, it attracted significantly fewer followers. This suggests that chemicals on the leader s abdominal part evoke tandem running. Dissection of abdominal major exocrine glands revealed that the Dufour s gland was the source of this chemical signal. The chemicals were eluted in the hydrocarbon fraction by silica-gel column chromatography, and the quantitatively major component was estimated as heptadecene (C17:1) through gas chromatograph-mass spectrometer (GC-MS) analysis. The position of the double bond was estimated to be between the 8th and 9 th carbons through analysis of the epoxidized compound. Only (2)-isomers of 8-heptadecene evoked tandem running in the followers. We identified the tandem running pheromone of this ant species to be (Z)-8-heptadecene (163).