Sequence of event delivery [i.e. US, CS and inter-trial interval (ITI)] during training sessions of the different experimental groups. BT, before training; CXM, cycloheximide; DEET, N,N-diethyl-meta-toluamide; LA, l-lactic acid; MYR, myrcene; OCT, 1-octen-3-ol; Pre-exp, pre-exposed; PT, post training; Z3H, Z-3hexen-1-ol.