ELECTROPHYSIOLOGICALRESPONSE PATTERNS OF 16OLFACTORY NEURONS FROMTHE TRICHOID SENSILLA TOODORANT FROM FECALVOLATILES IN THE LOCUST,Locusta migratoria manilensis

摘要

Locusts are the most serious pests of crops in greater part of the world. Theylocate their host plants primarily through olfactory cues, using antennalchemosensilla, which house olfactory receptor neurons (ORNs). Despite thegreat economical interest of these species, their olfactory neurons have beenpoorly investigated at the functional level. In this study, we have used singlesensillum recordings (SSRs) to obtain response patterns of ORNs from theantennal trichoid sensilla to various chemicals in the oriental locust Locustamigratoria. On the basis of their spontaneous spike amplitudes, trichoidsensilla could be distinguished into two types, housing two or three ORNs,respectively. These two structural types could be further classified into sevenfunctional subtypes. Nine different odorants that are present in the locust feceswere used as stimulants during SSRs. In particular, benzaldehyde elicited nhibitory responses in most of the ORNs tested. Moreover, in a majority of these ORNs, the excitatory responses obtained with trans-2-hexenal or2-heptanone was inhibited when benzaldehyde was mixed with thesestimulants. At least 16 response patterns of these ORNs to nine chemicals wereidentified by SSRs, suggesting a high complexity of the cellular mechanismsunderlying chemoreception in locusts.