Electroantennographic and coupled gas chromatographic-electroantennographic responses of the mediterranean fruit fly, Ceratitis capitata, to male-produced volatiles and mango odor

We have identified five compounds from the headspace of calling male Mediterranean fruit flies (medfly), Ceratitis capitata (Wiedemann), and three compounds from the headspace of ripe mango (Mangifera indica L). using coupled gas chromatographic-electroantennographic (GC-EAG) recordings, coupled gas chromatographic-mass spectrometric (GC-MS) analysis, and electroantennographic (EAG) assays of standards. The male-produced volatiles eliciting responses from female antennae were ethyl-(E)-3-octenoate, geranyl acetate, (E,E)-α-farnesene, linalool, and indole. An EAG dose-response test of linalool enantiomers and indole with female medfly antennae showed relatively strong EAG activities, but no significant difference between (R)-(-)-linalool and (S)-(+)-linalool. The three mango volatiles were identified as (1 S)-(-)-β-pinene, ethyl octanoate, and β-caryophyllene. In addition, a strong antennal response was recorded from a contaminant, α-copaene, present in a commercial sample of β-caryophyllene. The EAG response amplitudes from both male and female antennae to the above three mango volatiles were significantly greater than to a hexanol control. For both male and female medfly antennae, the greatest EAG responses were elicited by β-caryophyllene followed by ethyl octanoate. The mean EAG responses of female antennae to β-caryophyllene and (1 S)-(-)-β-pinene were significantly greater than those of male antennae.