Sexual attraction was observed inDacus oleae(Gmelin) which, as opposed to all other tephritid fruit flies examined, is generated by the females and is directed exclusively toward the males. It is conjectured that in this sexual attraction an airborne pheromone is involved. Daily rhythm and age at appearance of attraction in this species coincides with mating, which indicates that these 2 functions are associated. Sexual attraction seems to be regulated by light intensity and reaches maximum levels during the last hour of the photophase. Females start attracting males from the 2nd day of post-emergence life, while males respond to female attraction after the 3rd day of their adult life. In flies of the same age, sexual attraction begins after the 3rd day of their adult life, reaches maximum at the age of 7–11 days, and starts decreasing from the 17th day. Mated females lose their attractiveness for a period of at least 6 days.