Exposure to Tea Tree Oil Enhances the Mating Success of Male Mediterranean Fruit Flies (Diptera: Tephritidae)

Abstract

The aroma of various plant essential oils has been shown to enhance the mating competitiveness of males of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). Laboratory observations revealed that male medflies show strong short-range (<10 cm) attraction to tea tree oil (TTO hereafter) derived from leaves of the Australian plant Melaleuca alternifolia (Maiden & Betch) Cheel (Myrtales: Melastomataceae). The present study was undertaken to i) compare the attractiveness of TTO with that of trimedlure (the male lure routinely used in detection surveys) in field and field cage tests and ii) assess the influence of TTO exposure on male mating success under conditions of varying dose, duration of post-exposure (i.e., pre-test) interval, and access (contact possible or not) to the TTO source. Results showed that TTO-baited traps captured 50% as many males as trimedlure-baited traps in field cages but only 8% as many males as trimedlure-baited traps in the open field. Males exposed to pure TTO or dilutions of 50% and 5% TTO in hexane had higher mating success than non-exposed control males in tests conducted 1 d after exposure. TTO-exposed males also had a mating advantage when tested 3 d after exposure and when physical contact with the TTO source was prevented. In an additional experiment, TTO exposure was found to enhance the mating competitiveness of mass-reared, sterile males in competition against wild males for copulations with wild females in tests conducted 1 or 3 d after exposure.