Abstract: 1,7-dioxaspiro-[5.5]-undecane (1) production in glands associated with the rectalampulla of both sexes of wild and reared (virgin) Bactrocera oleae adults was investigated. Thepossible presence of 1 on urotergal gland extracts was also verified. Analyses were performed onglandular extracts by GLC and GLC/EI-MS. Results on the rectal extracts showed that underlaboratory conditions both sexes (wild and reared) of olive fruit fly begin to produce detectable 1from the 1st day after emergence, demonstrating that initiation of 1 production does not coincidewith sexual maturation. Female production of 1 was relatively greater than that of the male and 1was detectable at least until the 45th day of life. Male (wild and reared) production of 1 reached amaximum when gonad maturation was complete (5-8 days-old), thereafter decreasing to 0 by the11th day of life: after this period, no detectable amounts of 1 were recorded. Finally, analyses ontergal extracts showed that in wild and reared females a very low amount of 1 is detectable, butonly at maximum production of 1 in the rectum.