Chemical ecology of the meat ant, Iridomyrmex purpureus sens. strict.

Twelve volatile constituents have now been characterized from the common meat ant, Iridomyrmex purpureus sens. strict. 2,5-Dimethyl-3-ethyl-, 2,5-dimethyl-3-propyl- and 2,5-dimethyl-3-butyl-pyrazine were mandibular gland constituents, and in total represented < 1 ng/gland. The major constituents were confirmed as the known 6-methylhept-5-ene-2-one and the iridodials. The oxygenated compounds: 1,3,3-trimethyl-2,7-dioxabicyclo[2,2,1]heptane, not previously reported from an insect source, together with 2-acetyl-3-methylcyclopentene and 6-methylhept-5-ene-2-ol were minor products. Minor iridoids were 2-(3-methylcyclopentyl)propional, a dihydroneptalactone and an iridolactone, plus actinidine. The oxygenated volatiles and iridoids were isolated both from extracts of whole insects, and bodies of I. purpureus workers. The same chemical pattern was repeated in samples of I. purpureus sens. strict., collected over a wide area of south-eastern Australia. The several series of pyrazines, iridoids, carbonyl compounds and associated volatiles, together with the previously described hydrocarbons, serve to distinguish I. purpureus sens. strict. chemically.