Olfactory responses of the vine weevil, Otiorhynchus sulcatus, to tree odours

Abstract

Abstract. A Y-tube olfactometer and a still-air olfactometer were developed to determine the attractiveness of several host plants for the vine weevil (Otiorhynchus sulcatus (F.); Coleoptera: Curculionidae). Odours of weevil-damaged yew (Taxus baccata) and spindle trees (Euonymus fortunei) are attractive to the vine weevil, but Rhododendron and strawberry (Fragaria  ananassa) are not. Undamaged Euonymus is attractive to the weevils in springtime but not in late summer. When clean air or undamaged Euonymus is the alternative, weevils strongly prefer weevil-damaged Euonymus foliage, and this preference is retained throughout the year. Hence, plant damage plays a role in attraction of the vine weevil. In contrast to the permanent attractiveness of weevil-damaged Euonymus, mechanically damaged plants gradually lose the attractiveness that they have early in the growing season. This suggests that emission of volatiles, produced by the plants in response to weevil damage, is important for attraction of the weevils because the weevils may use these plant odours to find suitable food plants throughout the season. Apart from weevil-damage-related plant volatiles, green leaf volatiles must also play a significant role, as indicated by the fact that weevils prefer: early season, undamaged Euonymus over clean air; early season, mechanically damaged Euonymus over undamaged Euonymus; and, throughout the season, had no preference when mechanically damaged Euonymus is tested against weevil-damaged Euonymus. Thus, monitoring traps may be developed by the use of green leaf volatiles and/or herbivore-induced volatiles, as attractants.

Taxus baccata L.

“…(1997) record that taxoids from T. baccata act as pyrethroid insecticide synergists against O. sulcatus . Taxus baccata releases volatile compounds that attract the weevil (van Tol et al . 2000) – in dual‐choice olfactometer experiments, chambers containing yew sprigs attracted 88% of released weevils ( n = 40).…”

Chemical Cues for Host Location by the Chestnut Gall Wasp, Dryocosmus kuriphilus

“…Volatile compounds emitted upon mechanical and/or herbivore damage are important in the host selection process for several phytophagous insects (Loughrin et al, 1996;Dickens, 2000;Kalberer et al, 2001;van Tol et al, 2002). In some cases, a neutral effect of undamaged host plant material also has been recorded (Bolter et al, 1997;Ruther et al, 2000;van Tol et al, 2004).…”

“…2 g) included at least two leaves and three buds. Mechanical damage was achieved by cutting twigs into pieces (0.5 cm wide) (van Tol et al, 2002).…”

Duration of emission of volatile organic compounds from mechanically damaged plant leaves

“…VOCs emitted by plants can act as attractants or repellants to phytophagous insects (e.g., Visser, 1986;Mitchell, 1994;Zhang and McEvoy, 1995;Moyes and Raybould, 2001;van Tol et al, 2002;Heil, 2004;Junker and Blüthgen, 2008;Otalora-Luna et al, 2009;Piesik et al, 2011a;. Although undamaged plant leaves typically emit VOCs, physical damage usually causes them to emit additional compounds or greater amounts.…”