Behavioural response of C. sexmaculata to the volatiles from B. brassicae and cabbage.

The behaviour and orientation modifying cues from host plants and prey insects play vital roles in the process of host selection and acceptance by predators. So, we studied the volatile organic compounds of un-infested and infested cabbage plants by cabbage aphid, Brevicoryne brassicae, through Gas Chromatography-Mass Spectrometry (GC-MS). Overall, 58 and 50 compounds were identified in uninfested and infested cabbage plants through DCM and DEE extract, respectively. Based on the peak area from the GC-MS analysis, the volatile organic compounds from infested cabbage were significantly greater than that from un-infested cabbage extract. In the DCM extract, volatile compounds, notably Cyclohexasiloxane tetradecamethyl, Cyclopentasiloxane decamethyl, and 3-Hexen-1-ol were released in significant amounts. In the DEE extract, 3-Hexen-1-ol, (Z)-, Cyclohexasiloxane dodecamethyl, and Cyclopentasiloxane decamethyl were also released in substantial quantities. The Y-tube olfactometer study revealed that C. sexmaculata adults exhibited significantly greater attraction to the volatiles emitted from cabbage infested with aphids compared to any other extract. Additionally, their response time was notably shorter when exposed to the infested cabbage with aphid extract. The results indicated that the C. sexmaculata could discriminate the infested cabbage and significantly responded to the plant odour, which suggested that, the synomones (volatiles from cabbage plant) and kairomones (volatiles from aphid body) played a vital role in the orientation behaviour of C. sexmaculata to locate the cabbage aphid. [ABSTRACT FROM AUTHOR]