Table 2.

Response of Anopheles coluzzii to three bacterial C4-compounds tested in a dual-choice olfactometer in three concentrations in low density polyethylene (LDPE) sachets in the presence of the three-component basic blend consisting of NH₃, (S)-lactic acid, and tetradecanoic acid, with (+) or without (−) carbon dioxide. Control = basic blend (−) or basic blend + carbon dioxide (+). Data for four-component blends without carbon dioxide were taken from Verhulst et al. (2011a) and reproduced here for direct comparison. Values for control and treatment refer to the numbers of mosquitoes caught out of the total number that left the release cage (N) over six replicated tests (N _max = 180). Percentages refer to overall response. P-values are based on χ ²-tests

Compound added to basic blend	4.5 % CO2	0.01 %		0.1 %		1 %
		Control	Treatment	Control	Treatment	Control	Treatment
3-methyl-1-butanol	−	25	41	28	20	31	29
		P = 0.048 (N = 157, 42 %)		P = 0.25 (N = 158, 30 %)		P = 0.80 (N = 163, 37 %)
	+	37	43	25	48	26	27
		P = 0.50 (N = 174, 46 %)		P = 0.007 (N = 175, 42 %)		P = 0.89 (N = 171, 31 %)
3-methylbutanal	−	16	16	21	24	18	34
		P = 1.0 (N = 172, 19 %)		P = 0.65 (N = 158, 28 %)		P = 0.03 (N = 170, 31 %)
	+	49	46	63	34	42	56
		P = 0.76 (N = 169, 56 %)		P = 0.003 (N = 176, 55 %)		P = 0.16 (N = 178, 55 %)
3-methylbutanoic acid	−	18	30	24	33	25	22
		P = 0.08 (N = 161, 30 %)		P = 0.23 (N = 161, 35 %)		P = 0.66 (N = 163, 29 %)
	+	56	52	37	61	47	34
		P = 0.23 (N = 171, 68 %)		P = 0.02 (N = 175, 56 %)		P = 0.15 (N = 174, 47 %)