Use of honey bees (Apis mellifera L.) to detect the presence of Mediterranean fruit fly (Ceratitis capitata Wiedemann) larvae in Valencia oranges.

Background: When fruit deteriorates a characteristic profile of volatile chemicals is produced that is different from that produced by healthy fruits. The identification of such chemicals allows the possibility of monitoring the fruit for early signs of deterioration with biological sensors. The use of honey bees and other insects as biological sensors is well known. This study aimed to identify the volatiles produced by oranges infested with larvae of the Mediterranean fruit fly and to test the ability of honey bees, conditioned to this volatile chemical profile, to detect such oranges.

Results: Seventeen compounds that were present in higher concentrations in the volatile profiles of infested oranges than in those of insect-free fruits were mixed at the same relative concentrations as those in the collected volatiles of infested oranges. The synthetic mixture was used to train honey bees by classical Pavlovian conditioning and subsequent tests showed that they were then able to discriminate between medfly-infested and uninfested oranges.

Conclusion: This study demonstrates an innovative way of detecting, at an early stage, the symptoms of damage to oranges by the Mediterranean fruit fly.