Technical Abstract: Secondary metabolites emitted from plants and natural essential oils are suspected to attract males of the Mediterranean fruit fly to their calling sites. We investigated the differential attractiveness of six essential oils that have either been shown to have aromatherapy effects and/or that differed in their volatile emission of a-copaene – a suspected attractive chemical. Attraction to essential oils was tested for (1) sterile males in field cage bioassays conducted in Florida and (2) wild flies in field tests conducted in Honduras. Substrates were tested as baits in Jackson traps (both sites) and sticky traps (field cage tests). Antennal response was measured with electroantennography using sterile males. Results were used to evaluate the role of a-copaene in attraction of males to these substrates.