Feeding deterrence of verbenone to the pine weevil, <i>Hylobius abietis</i> (L.) (Col., Curculionidae)

Abstract

Abstract: Exposure to verbenone vapours did not cause any acute toxicity symptoms in the pine weevil, Hylobius abietis , whereas weevils exposed to higher doses of both limonene and α‐pinene exhibited signs of poisoning within a few h. Verbenone consistently suppressed feeding, while symptom‐free weevils exposed to limonene or α‐pinene fed as much as controls. Feeding in verbenone‐exposed weevils remained suppressed 20 h after the insects had been transferred from the exposure vials, whereas weevils exposed to limonene and α‐pinene resumed normal feeding soon after transfer. Feeding deterrence by verbenone was lost after 48 h, and starved weevils were less deterred than fed weevils. Feeding was also reduced by weevils offered food contaminated by verbenone, indicating that acute toxicity effects were not responsible for the reduced feeding observed in weevils exposed to verbenone vapors. Feeding deterrence by verbenone is hypothesized to be due to its association with microbial breakdown of host tissues, indicating sub‐optimal food quality.