A Preliminary Study of Host Selection and Acceptance Behaviour in the Cabbage Aphid,Brevicoryne BrassicaeL

Abstract

The present study investigates the role of the chemical senses in host selection and acceptance behaviour of the cabbage aphid Brevicoryne brassicae L. In order to determine the composition of this behaviour we observed aphids on hosts, non hosts and intermediate plants on which the aphid incidentally occurs (Markkula, 1953): non-cruciferous plants which contain mustard oil glucosides. About fifteen different behavioural components were distinguished and scored during a period of 30 minutes after an aphid had benn put on a plant. On formal grounds we used 1he term “proboscis contact” (p.c.) instead of “probe”. Some authors (cf. Klingauf, 1971) use the duration of the first walk or the first probe as parameters in host selection behaviour. In our experiments the frequency of p.c., its mean duration and the percentage of time spent in p.c. were used. These parameters appeared to be less sensitive to pretreatments and reflected greater differences between the various plant species than the duration of the first walk or first probe. Apterous adults showed (Fig. 1) on the host Brussica oleracea a relatively low frequency of p.c. compared to aphids on the non host Vicia faba. The mean duration of p.c. and the percentage of time spent in p.c. were relatively high on host-plants. Compared with Brassica, Tropaeolum majus was, under our experimental conditions, an equally attractive host for aphids. Similar results were found with alate insects (Fig. 2). Aphid behaviour on Reseda odorata may be described as intermediate as compared to Brassica and Vicia.