Olfactory response of female Bactrocera minax to chemical components of the preference host citrus volatile oils

Citrus fruit fly Bactrocera minax (Enderlein) (Diptera:Tephritidae) is a devastating pest of citrus plants in China. In order to characterize the behavioral mechanisms and possible chemical cues involved in host selection by female citrus fruit fly, the host plant volatiles was analyzed and Y-tube olfactometer assays were used. Host odor from citrus fruits peels elicited upwind orientation flights followed by landing and egg-laying, demonstrating the essential role of host plant volatiles in B. minax host-finding and oviposition behavior. GC–MS analysis of volatiles from the peels of three varieties citrus fruits, that were Bingtang sweet oranges ( Citrus sinensis cv. Bingtang), Satsumas mandarins ( Citrus reticulata cv. Satsuma) and Sour oranges ( Citrus aurantium ), which adult and larval of B. minax preferred to, showed that the major compounds extracted from the basal region were different from those of the distal region to some extent. Furthermore, in Y-tube olfactometer attraction assays, female flies were significantly attracted ( P   <   0.05) to four out of the thirteen tested compounds from the citrus volatiles, including nonanal , citral , limonene and linalool . Conversely, furfuryl alcohol and guaiastil significantly repelled females ( P   <   0.05). The percentage composition of nonanal, citral, limonene and linalool from different regions of the fruits displayed a positive correlation with the numbers of egg marks made by females, whereas furfuryl alcohol and guaiastil displayed a correspondingly negative correlation. These results suggest that the oviposition preference of B. minax females is highly related to the chemical compounds emitted from host fruit peels.