Olfactory Responses of Asproparthenis punctiventris Germar to Leaf Odours of Amaranthaceae Plants

Abstract

Understanding the stimuli used by insect pests to find their food plants can be a first step towards manipulating their behaviour and, thus, controlling them. We investigated the responses of the sugar beet weevil Asproparthenis punctiventris (Coleoptera: Curculionidae) to the volatile leaf odours of its food plants, including Beta vulgaris subsp. vulgaris (Altissima and Cicla groups), Atriplex hortensis, Chenopodium album, and Amaranthus retroflexus, in a four-arm olfactometer. A bioassay procedure was developed, and the frequency of visits and time spent by adult weevils in the quadrant of the olfactometer with leaf volatiles was recorded, as was their first choice of quadrant. Females and males were equally attracted to the leaf odours of young B. vulgaris subsp. vulgaris plants, i.e., sugar beet and chard, as indicated by the overall picture of the behavioural parameters analysed. Males, but not females, responded positively to the leaf odour of the garden orache (A. hortensis), and no response was observed when the weevils were tested with the leaf odours of fat hen (C. album) or common amaranth (A. retroflexus). These results suggest that A. punctiventris uses leaf odours to locate sugar beet and other food plants. Knowledge of the olfactory responses of this pest can provide a basis for improved monitoring or mass trapping strategies.