抄録
The olfactory response of adults of Luehdorfia japonica (Papilionidae) to floral volatiles from Prunus yedoensis (Rosaceae) was investigated by means of a behavioral test (reflex extension of proboscis : REP) and electroantennographic (EAG) responses. Chemical analysis of the flower extract revealed that the floral scent consisted mainly of aromatic compounds, among which benzaldehyde (BAL, ca. 33%) was the dominant component. Of 10 floral volatiles tested, phenylacetaldehyde (PAL) elicited the highest REP response from both sexes. The REP-eliciting activities of benzyl alcohol, 2-phenylethanol and BAL, though a little lower than that of PAL, were also relatively high (ca. 50%) compared with those of other floral components. These four compounds, therefore, were considered to be the olfactorily active principles that stimulate foraging behavior in the butterfly. In EAG experiments with ten test chemicals, differences in responsive intensities among these compounds were not remarkable at a dose of 1 μg. In contrast, males displayed stronger EAG responses to ethyl phenylacetate, linalool, BAL and PAL at a dose of 100μg. The present findings indicate that the antennal sensitivity of the butterfly is not necessarily correlated with the REP behavior. Although we found no explanation for conspicuous male EAG responses to particular components, this phenomenon seems suggestive of additional and as yet unknown functions(s) of these compounds in the life of the male butterfly.
