Table 1.

Location of the different classes of bitter-sensitive taste cells in M. sexta

Sensillum	Bitter taste stimulus
	Grindelia extract	Canna extract	Aristolochic acid	Caffeine	Salicin
Maxillary palp	X
Medial styloconic		X	X
Lateral styloconic			X	X	X
Epipharyngeal		X	X	X	X

We use an X to indicate the bitter-sensitive taste cells that are sufficient to mediate an aversive response to each of the five bitter taste stimuli (data from de Boer and Hanson, 1987;Peterson et al., 1993; Glendinning et al., 1998, 1999). The excitatory response of each bitter-sensitive taste cell to each of the bitter taste stimuli is provided in Figure 2.