Figure 4. Geosmin as a Potential Mosquito Control Agent.
(A) Map over greater Miami area with trap sites marked. Satellite image courtesy of Google Maps.
(B) Oviposition trap used for the field experiments.
(C–E) OIs from Miami mosquitoes offered a choice between control traps (water only) and traps baited with geosmin. Each data point represents the average OI from a single site (n = 11–14). Total number of eggs is as follows: (C) 2,240, (D) 2,594, (E); 2,946; (C) geosmin (10−3) 31 ± 6 eggs per trap, control 24 ± 5; (D) geosmin (10−4) 35 ± 6, control 26 ± 4; (E) geosmin (10−5) 39 ± 8, control 31 ± 6 (mean ± SEM). Boxplots and statistics as per Figure 1C are shown.
(F) OIs of WT mosquitoes (20 mosquitoes per trial; n = 6 trials) from binary-choice tests between whole beetroot extract and water. Boxplots and statistics as per Figure 1C are shown.
(G) FID traces from a gas chromatography-mass spectrometry analysis of head space comparing volatiles emitted from beetroot peel and beetroot pulp.
(H) Pseudocolor plot of ΔF/F0 calcium responses (0 to 1 scale) to beetroot peel and pulp, at a depth of 75 μm from the surface of the AL.
(I) PD3 responses (ΔF/F0) to the extracts of the beet rind (brown), pulp (purple), and solvent (methanol) control (blue). Grey bar denotes the time course of odor stimulus. Traces are the mean; area is the SEM (n = 3 mosquitoes). Shown in the inset are mean responses to the extract. Letters denote significant differences between stimuli (Kruskal-Wallis test: χ = 63.19, p < 0.0001; multiple comparisons: p < 0.05).
(J) OIs of WT mosquitoes (20 mosquitoes per trial; n = 6 trials) from binary-choice tests between whole beetroot peel and pulp. Total number of eggs is as follows: 2,878; peel 322 ± 82 eggs, pulp 158 ± 41 (mean ± SEM). Boxplots and statistics as per Figure 1C are shown.
(K) Brazil field site. Satellite image courtesy of Google Maps.
(L) Oviposition trap constructed from painted PET bottles lined with filter paper used for the experiments in Brazil.
(M) OIs from wild Brazilian mosquitoes offered a choice between control traps (water only) and traps baited with beetroot peel extract. Each data point represents a collection event. Total number of eggs is as follows: 1,630; peel 45 ± 7 eggs, control 18 ± 3 (mean ± SEM). Boxplots and statistics as per Figure 1C are shown. See also Figure S2.