Mandibular gland allomones ofDasymutilla occidentalis and other mutillid wasps

The mandibular gland secretion of the mutillid wasp,Dasymutilla occidentalis, possesses three short-chained ketones-4-methyl-3-heptanone (4MH), 4,6-dimethyl-3-nonanone (4,6DMN), 4,6-dimethyl-3-octanone (4,6DMO)—and several unidentified compounds. This is the first report of 4,6DMN as a natural product and its synthesis is described. These ketones, which are either known to be ant alarm pheromones or are structurally very similar to ant alarm pheromones, appear to function as allomones against ants, major potential predators of mutillid wasps. The major secretory component, 4-methyl-3-heptanone, which was identified in females and/ or males of the species analyzed within the generaDasymutilla, Timulla, Traumatomutilla, andPappognatha, appears to constitute a chemical character of the defensive secretions of these genera.