Identification of volatile cues that attract and elicit response in aphid (Brevicoryne brassicae) to its host cabbage (Brassica oleracea var. capitata)
IIHR, Bengaluru, India Bengaluru, Karnataka, India
Behavioural studies on the attraction of aphids to host crops, though important, are still not exhaustive in some aphids’ species. Notwithstanding, most investigations focused mainly on pests to host-plant attractions with limited accounts on whether attractions might be mediated by both conspecific and heterospecific chemical signals. Here, our goal was to identify those chemical cues that might attract and elicit the cabbage aphids (Brassica oleracea) response towards cabbage, taking into account both heterospecific and conspecific infested plant volatiles release. We collected volatiles from healthy cabbage, aphids and diamondback moth (DBM) larvae-infested cabbage and aphids' body volatiles. We conducted a series of behavioural choice olfactometer assays, electrophysiological studies and gas chromatography coupled to masspectrometry analysis to specify any chemically active compounds inviting aphids. Our result indicated that the cabbage aphids were mostly attracted to aphids-infested cabbage volatile cues although, there were also indications that uninfested and DBM larvae-infested cabbage had similar preferences to the aphids. Furthermore, aphids that were exposed to aphids’ body odour, showed that they could discriminate and were the least attracted to it. Electrophysiological antennae response, plus GC-MS analysis revealed some chemically active compounds that elicited the insect pest response, with more of these compounds in the aphids-infested cabbage than in the rest of the treatments. It is possible that the knowledge gained from this work could pave the way for synthetic lures. Therefore, more studies would need to be conducted to validate and isolate those exact compounds that positively excited the cabbage aphids’ olfactory response.