Table 1. The final population density (N) of species of mites on antibiotic additive diets and fitted concentration EC₅₀ is an effective concentration of antibiotic s in diets for 50% population growth reduction in the comparison to growth on control diet.

Species	Antibiotics (mgg−1)	Observed data (N)					Regression model
		0	0.1	1	10	30	R2	a	b	c	Fit EC50 mgg−1
Acarus siro	Ampicillin	1183	728	484	275	200	0.95	−2.95	−89	513	0.37
		(71)	(111)	(25)	(47)	(56)		(−3.7/−2.2)	(−100/−78)	(483 /543)	(0.20/0.55)
	Neomycin	1179	1059	501	391	304	0.87	−5	−115	689	2.23
		(74)	(89)	(73)	(24)	(57)		(−7/−4)	(−133/−96)	(640/739)	(1.11/3.67)
	Streptomycin	1280	1118	883	452	292	0.94	−7	−142	847	4.95
		(102)	(97)	(49)	(71)	(41)		(−8 /−6)	(−155/129)	(811/882)	(3.52/7.03
Lepidoglyphus destructor	Ampicillin	1718	1398	1144	603	185	0.87	−10	−202	1060	2.66
		(108)	(208)	(129)	(216)	(57)		(−12/−8)	(−231/−173)	(982/1139)	(1.51/7.03)
	Neomycin	1685	414	338	197	116	0.98	2	−56	304	0.0004
		(105)	(60)	(60)	(40)	(26)		(1/3)	(−66/−45)	(275/332)	(0.0001/0.001)
	Streptomycin	1685	1465	1106	428	231	0.93	−11	−214	1050	2.38
		(96)	(218)	(161)	(68)	(51)		(−12/−9)	(−236/−191)	(990/1110)	(1.7/3.07)
Tyrophagus putrescentiae	Ampicillin	1164	415	297	156	131	0.97	0.1	−51	293	0.003
		(95)	(36)	(18)	(20)	(18)		(−0.4/0.6)	(−60/−44)	(272/314)	(0.001/0.01)
	Neomycin	1271	751	639	290	139	0.95	−4	−108	569	0.76
		(75)	(103)	(63)	(36)	(37)		(−5/−3)	(−120/−96)	(537/602)	(0.41/1.21)
	Streptomycin	1193	1111	411	355	148	0.85	−7	−140	661	1.58
		(98)	(144)	(48)	(41)	(16)		(−8/−5)	(−164/−118)	(599/724)	(0.74/2.66)

Legend: The final population density is expressed as mean ± standard deviation; the polynomial regression (r = ax2+bx+c; x = antibiotic concentration mgg−1 of diet) describing the suppressive effect of antibiotics to growth rate of tested mites. The antibiotic concentration was transformed logarithmically (LN concentration +1×10⁻⁷). The fitted parameters are showed with 95% confidence limits in parenthesis.