A bioelectronic interface based on the coupling of an intact insect antenna to a field-effect transistor (FET) has been realised in a whole-beetle BioFET (Biologically sensitive FET) and an isolated-antenna BioFET configuration. The intrinsic BioFET characteristics, such as current-voltage curves, transconductance and signal-to-noise ratio clearly depend on the chip layout. Therefore, the experiments were performed with three different gate geometries: linear shape (5 mu m x 100 mu m), U shape (5 mu m x 1000 mu m) and meander shape (10 mu m x 6000 mu m). The BioFET allows the determination of the ＇green-leaf odour＇ Z-3-hexen-1-ol down to the low ppb concentration range. Thus, the detection of plant damages is possible with this novel kind of biosensor.