J. Insect Physiol., 1972, Vol. 18, pp. 1077 to 1088. Pergamon Press. Printed in Great Britain zyxwvutsrqponmlkjihgfedcb ALARM PHEROMONES IN THE GENUS zyxwvutsrqponmlkjihgfedcbaZYXWVUT MANICA DERIVED FROM THE MANDIBULAR GLAND H. M. FALES,l M. S. BLUM,2 R. M. CREWE,2 and J. M. BRAND2 zyxwvutsrqponmlkjihgfedcbaZYXWVUT l Laboratory of Chemistry, National Heart and Lung Institute, Bethesda, Maryland 20014; and * Department of Entomology, University of Georgia, Athens, Georgia 30601 (Received 13 December 1971) zyxwvutsrqponmlkjihgfedcbaZYXWVU Abstract-The alarm pheromones present in the mandibular glands of Manica mutica and M. bradleyi are dominated by a novel Cl,, ketone, 4,6- dimethyl-4-octene-3-one (manicone). Two other new insect pheromones, 4-methyl-3-hexanone and 3-decanone, are also present. In addition, two characteristic myrmicine alarm pheromones, 3-octanone and 4-methyl-3- heptanone, have been identified as mandibular gland constituents. W hile manicone functions as a powerful releaser of alarm behaviour for Manica workers a much weaker response was obtained to the other identified 3-alkanones. The significance of the occurrence of 3-ketones in members of the genus Manica and species in other genera of the Myrmicinae is analysed in terms of the accepted phylogeny of this subfamily. INTRODUCTION THE THOROUGH comparative investigation of European Hymenoptera by MASCHWITZ (1964) clearly established that alarm pheromones generally are not highly specific for species within a genus. However, in the formicid genus Mymtica, Maschwitz reported that the mandibular gland pheromone of one species, M. rubida, was not highly excitatory for three other species in this genus and vice versa. Furthermore, he noted that the odour of the mandibular gland products of M. rubida smelled differently from those of the other species of Myrmica. The apparent singularity of the alarm-releasing specificity of the Myrmica rubida pheromone loses some of its significance when it is realized that in actuality this species is a member of another myrmicine genus. M. rubida and its four North American congeners have been removed from the genus Myrmica (WEBER, 1947; CREIGHTON, 1950) and assigned to the genus Manica, a taxonomic develop- ment which has been amply supported by a recent detailed investigation of this myrmicine taxon (WHEELER and WHEELER,1970). We have also noted that the odour of the mandibular gland secretion of North American species of Manica differed significantly from any species of Myrmica which we have examined. Because the chemistry of the alarm pheromone of Myrmica species has recently been described (CREWE and BLUM, 1970a, b) , 1077