Attractiveness and ovipositional responses of volatile organic compounds from preferred host fruits to <i>Bactrocera dorsalis</i> (Diptera: Tephritidae)

The oriental fruit fly Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is an invasive and highly polyphagous insect species that affects more than 470 plant species. In recent years, its presence has been repeatedly recorded in trap networks in Europe, raising concern about the potential pest establishment in that area. Currently, early detection of its presence relies on the use of traps baited with methyl eugenol, which is highly effective in attracting males. However, there are currently no particularly effective or specific attractants for adult females. Identifying new attractants, particularly targeting females, is therefore crucial to improve trap efficacy. Female olfactory responses and oviposition behavior are influenced by chemical cues emitted from host fruits. The aim of this study was to evaluate the ovipositional responses of 14 volatile organic compounds emitted by fruits of preferred hosts and to determine their attractiveness to laboratory-reared oriental fruit fly adult females under controlled conditions. To this end, no choice and dual choice ovipositional experiments, as well as dual choice behavioral assays, were conducted. Many of these volatile organic compounds were found to stimulate oviposition and being attractive to B. dorsalis females with γ-octalactone showing the highest activity. Overall, ethyl octanoate, ethyl hexanoate, butyl hexanoate, hexyl hexanoate, γ-octalactone, and linalyl acetate were the most effective compounds in attracting adult females and eliciting high ovipositional responses. These chemicals appear promising for the development of new, female-specific attractants that can be used in new tools for integrated pest management programs.