Synergistic and additive interactions among components of food‐based baits underlie female fruit fly attraction

Abstract

Attraction of tephritid fruit flies to some food sources can be enhanced by the presence of ammonia derivatives, compounds that are perceived as volatile cues for protein-rich food sources. Using a comparative approach, we (1) evaluated the behavioral responses of females of three invasive fruit fly species, Bactrocera (Zeugodacus) cucurbitae (Coquillett), Bactrocera dorsalis (Hendel), and Ceratitis capitata (Wiedemann) (all Diptera: Tephritidae) to trub (a protein-rich waste brewer's yeast product generated during the production of beer), Concord grape juice (a protein-deficient material), and ammonium acetate, and (2) identified synergistic and additive interactions between low-and highattractiveness materials and ammonium acetate. We established the attractiveness of fresh trub, grape juice, and ammonium acetate when tested singly to females of all three fly species. Although ammonium acetate did not enhance significantly the response of females of any species to fresh trub, the most attractive material, ammonium acetate, did significantly enhance females' level of response to aged trub (a comparatively less attractive material) and to grape juice. Our research found a synergistic interaction between diluted grape juice and ammonium acetate for B. cucurbitae, as well as between aged trub and ammonium acetate for B. dorsalis. For C. capitata, additive effects among food attractants and ammonium acetate were identified. Our findings increase our understanding of fruit fly female olfactory-driven behavior in response to food-based materials and the extent to which ammonium acetate modulates female response to protein-rich and protein-deficient materials.

Does Ammonia Released from Protein-Based Attractants Modulate the Capture of Anastrepha obliqua (Diptera: Tephritidae)?

“…Although ammonia seems to be a key attraction component, our results agree with previous studies in which ammonia alone did not fully account for the attraction of flies [9,15,16,21,28,29]. This was corroborated in our experiments, in which the capture of flies was significantly improved when torula yeast was added to 150 mM ammonia solution ( Table 2).…”

“…Ammonia is considered one of the most important components that modulate tephritid responses to food-based attractants [ 9 , 10 , 15 , 17 ]. Tephritid species vary in their responses to sources of ammonia, which appear to be capable of both additive and synergistic effects if other food-based substances are present, such as grape juice or protein-rich waste from the brewing industry at different stages of decomposition [ 21 ].…”

“…This may be due to the somewhat complex procedures required to quantify ammonia emissions. As a result, most studies have been performed using ammonia solutions of known concentration and dry protein-based attractants [ 9 , 10 ], patches containing ammonium salts [ 18 , 19 , 20 ], or mixtures of food-based baits with ammonium bicarbonate or ammonium acetate [ 15 , 17 , 21 ].…”

Addition of Ammonium Acetate to Protein-Borax Baited Traps Does Not Improve Attraction ofAnastrepha obliquaorAnastrepha serpentina(Diptera: Tephritidae)

“…To our knowledge, this is the first study to evaluate the incorporation of ammonium acetate into protein-borax mixtures used in monitoring traps. Although attraction appears to vary across species, these findings reinforce previous observations that have indicated that the amount of ammonia released by food-based substances is less influential on the attraction of tephritid flies when other protein-derived odors are also present ( Piñero et al 2020 ; Lasa and Williams 2021 ). Additional studies on protein-derived semiochemicals and their interaction with ammonia could lead to improved attractants for trap-based monitoring of tephritid pests.…”

“…The attraction of Ceratitis, Bactrocera, and Zeugodacus species to proteinaceous and non-proteinaceous substances was studied by Piñero et al (2020) , with and without the addition of ammonium acetate. These authors observed that ammonia tended to be less attractive to tephritids when protein-derived odors were also present.…”