The cuticular hydrocarbons ofFormica selysi (Formicinae) andMonica rubida (Myrmicinae) reared in single species and in mixed species colonies were determined using gas chromatography (GC) and GC-mass spectrometry. In colonies containing both species, each species modified its species-specific recognition odor. This odor is composed, at least partly, of cuticular hydrocarbons. The cuticular hydrocarbons ofM. rubida consist only of saturated alkanes (n-alkanes and branched alkanes). InF. selysi the mixture also contains unsaturated compounds (monoenes and dienes). In hetero-specific colonies, a new chemical signature developed. This signature resulted from qualitative and quantitative changes in the spectrum of hydrocarbons produced by each species and permitted the two species to inhabit the same nest without displaying interspecific aggression. The readjustment seemed to be more an active synthesis or an active transfer than simply a passive transfer from one species to the other. This may imply that the ants synthesized some components of the hydrocarbon signature of the other species. These synthesizing processes may be activated under particular social environmental conditions.

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Detoxification of E destruxin in E-diol-destruxin in uiuo inLocustu migrutoriu locust is demonstrated using direct fast-atom bombardment (FAB) mass spectrometry without the need for extraction or purification. Organs and biological fluids are used as biomatrices for the FAB desorption process.In most cases, research into metabolic profiles from biological fluids has been difficult because it has involved solvent or acido-basic extractions, and purifications using different kinds of liquid chromatography (LC) prior to fast-atom bombardment mass spectrometry (FAB-MS) or fast-atom bombardment followed by tandem mass spectrometry (FAB-MS/MS) analysis. These processes have already been used for quantification or purification of the endogenous opioid pentapeptide leucine-enkephalin in a canine caudate nucleus tissues extract' or for analysis of acylcarnitines in human urine, blood or tissues.' Recognition of destruxins from dead caterpillars of Manduca sexta required multiple stages of purification using reversed phase high performance liquid chromatography (HPLC) before analysis using FAB-MS as a means of determi-