Research Articles Experientia 46 (1990), Birkh/iuser Verlag, CH-4010 Basel/Switzerland Anticipatory intervals (average values with standard deviation) 763 Tones in pattern Before 1st tone Before 2nd tone Before 3rd tone Before 4th tone Sequence-condition 1 (500 ms intertone interval) - 32.6 (_ 36.7) - 31.8 (• 38.4) - 30.4 (• 35.2) - 32.3 (+ 34.8) Sequence-condition 2 (700 ms intertone interval) - 28.6 (+_ 37.3) - 30.4 (+_ 39.4) - 36.9 (_+ 42.6) - 34.1 (_ 38.4) Minus sign means tapping onset precedes stimulus onset. For details see text. The acoustic system is capable of differentiating much shorter time intervals between tones than 30 ms 14. It is therefore obvious that the anticipatory error in following rhythmic stimuli is not caused by functional limitations of hearing. Instead, it is apparently related to temporal programming of a highly automatized, stereotypically repeated sequence of simple and probably ballistic move- ments. Because the response is anticipatory it is obvious- ly not related to the stimulus proper but to the preceding stimulus, 500 or 700 ms earlier. As there is no difference in anticipation for the two interstimulus conditions (see table), the discrete temporal advance by approximately 30 ms is embedded in a higher order temporal control mechanism. Thus, not only temporal control in the per- ceptual domain, but also in the sensorimotor domain appears to be organized in a hierarchical way 15. 1 This work was supported by DFG, Po 121/13. 2 Fraisse, P., L'ann6e psycho1. 66 (1966) 15. 3 Fraisse, P., in: Psychology of Music, p. 119. Ed. D. Deutsch. Aca- demic Press, New York 1982. 4 Clynes, M., and Walker, J., in: Music, Mind and Brain, p. 171. Ed. M. Clynes. Plenum Press, New York 1981. 5 Franek, M., Radil, T., and Indra, M., Activitas uerv. sup. 27 (1985) 222. 6 Franek, M., Radil, T., Indra, M., and Lfinsky, P., Int. J. Psycho-phys- iol. 5 (1987) 187. 7 P6ppel, E., Psychol. Forsch. 43 (1970) 1. 8 P6ppel, E., in: Handbook of Sensory Physiology, Vol. VIII, Percep- tion, p. 713 Eds R. Held, H. Leibowitz and H.-L. Teuber. Springer, Berlin 1978. 9 Galambos, R., Makeig, S., and Talmachoff, P. J., Proc. natl Acad. Sci. USA 78 (1981) 2643. 10 Ilmberger, J., Naturwissensehaften 73 (1986) 743. 11 P6ppel, E., and Logothetis, N., Naturwissenschaften 73 (1986) 267. 12 Madler, Ch., and P6ppel, E., Naturwissenschaften 74 (1987) 42. 13 Gray, C. M., K6nig, P., Engel, A. K., and Singer, W., Nature 338 (1989) 334. 14 Hudspeth, A. J., Nature 341 (1989) 397. 15 P6ppel, E., Mindworks. Time and Conscious Experience. Harcourt Brace Jovanovich, Boston 1988. 0014-4754/90/070762-0251.50 + 0.20/0 O Birkhfiuser Verlag Basel, 1990 Gustatory sensitivity of an anuran to cantharidin 1 S. T. Kelling, B. P. Halpern and T. Eisner Department of Psychology and Section of Neurobiology and Behavior, Cornell University, Ithaca (New York I4853, USA) Received I1 December I989; accepted 22 February I990 Summary. Glossopharyngeal nerve stimulation of the bullfrog, Rana eatesbiana, revealed responsiveness to low levels of cantharidin (1.3 x 10-6 M), providing a first demonstration of neural gustatory sensitivity of an animal to this defensive chemical from blister beetles (Meloidae). Key words. Cantharidin; taste; glossopharyngeal nerve; Amphibia; Meloidae. Cantharidin, the active principle of 'Spanish Fly', is one of the oldest-known poisons of insect origin 2. Present as a defensive agent in the blood of blister beetles (family Meloidae) at concentrations in the order of 10 -1 to 10-3 M, it is a strong feeding deterrent to ants and cara- bid beetles a, and toxic to many vertebrates 4. Nonethe- less, several invertebrates 3, 5, as well as vertebrates such as Japanese quail 6, armadillos 7, and a number of Am- phibia s, 9, are able to eat blister beetles with apparent impunity. We here present evidence that in one known predator of blister beetles, the bullfrog Rana catesbiana 9 the ability to consume these insects is not attributable to an inability to taste cantharidin. We have shown this frog to have a high neural gustatory sensitivity to this com- pound, a capacity not previously demonstrated for an animal. The experiments were carried out on 5 wild-caught bull- frogs (Ithaca, New York; body mass 48 -t- 14g). Each was anesthetized (10% aqueous urethane, intraperi- toneal, 20 mg/kg b.wt), placed ventral side-up with the