Identification of Glutamic Acid as a Host Marking Pheromone of the African Fruit Fly Species Ceratitis rosa (Diptera: Tephritidae)

Host marking pheromones (HMPs) deposited by female fruit flies deter other females from overexploiting the same fruit for egg laying. Using a bioassay-guided approach, we identified the HMP of the Natal fruit fly species Ceratitis rosa as glutamic acid, 1, from the aqueous fecal matter extract of ovipositing females by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Dual choice oviposition assays showed that both the fecal matter extract and 1 significantly reduced oviposition responses in conspecific females of C. rasa. Glutamic acid levels were 10-20 times higher in fecal matter than in the ovipositor or hemolymph extracts of females. Identification of 1 as a host marking pheromone in females of C. rosa improves our understanding of fruit fly chemical ecology and provides evidence that it could be used as a potential component in the integrated management of this fruit fly species.