Identification of glutamic acid as a host marking pheromone of the African fruit fly species Ceratitis rosa (Diptera: Tephritidae)

Authors: CHESETO, XAVIER - International Centre Of Insect Physiology And Ecology; KACHIGAMBA, DONALD - Bvumbwe Agricultural Research Station; BENDERA, MWANASITI - International Centre Of Insect Physiology And Ecology; EKESI, SUNDAY - International Centre Of Insect Physiology And Ecology; NDUNG'U, MARY - Jomo Kenyatta University; Beck, John; TORTO, BALDWYN - International Centre Of Insect Physiology And Ecology

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2018
Publication Date: 9/5/2018
Citation: Cheseto, X., Kachigamba, D.L., Bendera, M., Ekesi, S., Ndung'U, M., Beck, J.J., Torto, B. 2018. Identification of glutamic acid as a host marking pheromone of the African fruit fly species Ceratitis rosa (Diptera: Tephritidae). Journal of Agricultural and Food Chemistry. 66(38):9933-9941. https://doi.org/10.1021/acs.jafc.8b04481.
DOI: https://doi.org/10.1021/acs.jafc.8b04481

Interpretive Summary: Certain chemical compounds left behind by female fruit flies that have just deposited their eggs (ovipositing) have the ability to deter other fruit flies from depositing eggs at the same site, which are typically on a fruit or other agricultural host plants. These chemical compounds are called host marking pheromones (HMPs). Scientists from the International Centre of Insect Physiology and Ecology (icipe) in collaboration with USDA-ARS scientists from the Center of Medical, Agricultural and Veterinary Entomology in Gainesville, FL report the identification of the HMP, glutamic acid, of the African fruit fly. The identification of glutamic acid as a host marking pheromone in females of the African fruit fly improves our understanding of fruit fly chemical ecology, and that glutamic acid could be used as a potential component in the control and management of this fruit fly species.

Technical Abstract: Host marking pheromones (HMPs) deposited by female fruit flies deter other females from over-exploiting the same fruit for egg laying. Previously, we reported identification of the HMP of the African indigenous mango fruit fly species Ceratitis cosyra as glutathione. Here, we identify the HMP of the Natal fruit fly species C. rosa as the amino acid glutamic acid (GA) from the aqueous fecal matter extract of ovipositing females. GA was characterized by liquid chromatography–quadrupole time of flight–mass spectrometry (LC-QTOF-MS). Dual choice oviposition assays showed that GA significantly reduced oviposition responses in conspecific females of C. rosa. Comparison of GA levels in fecal matter extracts across the life span of females showed positive correlation with age of females, with optimal amounts detected in fecal matter of approximately 2-week-old adult females. GA levels were 10-20 times higher in fecal matter than in the ovipositor or hemolymph extracts of females. Identification of GA as a host marking pheromone in females of C. rosa improves our understanding of fruit fly chemical ecology, and that GA could be used as a potential component in the integrated management of this fruit fly species.