Ability of near-infrared spectroscopy and chemometrics to predict the age of mosquitoes reared under different conditions

Table 1 Predictive power of models derived from different Ae. albopictus populations

Actual age (days)	No. scanned	Standard PLS		Resampling PLS
Actual age (days)	No. scanned	Age in days	Classed as old (%)	Age in days	Classed as old (%)
Using laboratory-derived models to predict the age of laboratory-reared mosquitoes
Number of components		8		10
2	41	3.58 (0.28)	0	2.13 (0.22)	4
5	42	7.62 (0.30)	36	7.27 (0.23)	9
8	42	8.35 (0.27)	60	8.07 (0.21)	57
12	42	8.47 (0.33)	57	9.84 (0.22)	58
15	44	14.0 (0.33)	100	14.7 (0.26)	68
Overall accuracy		RMSD = 2.38	–	RMSD = 2.89	AUC = 0.88
Using field-derived models to predict the age of field-derived reared mosquitoes
Number of components		8		10
1	50	4.58 (0.32)	6	3.31 (0.28)	0
7	50	7.71 (0.44)	41	7.28 (0.36)	0
14	100	11.7 (0.34)	90	12.7 (0.26)	100
Overall accuracy		RMSD = 3.41	–	RMSD = 2.82	AUC = 0.97
Using laboratory-derived models to predict the age of field-derived reared mosquitoes
Number of components		8		10
1	50	6.50 (0.20)	12	8.23 (0.18)	36
7	50	6.92 (0.20)	18	9.40 (0.27)	74
14	100	7.00 (0.15)	24	9.18 (0.22)	75
Overall accuracy		RMSD = 5.84	–	RMSD = 5.42	AUC = 0.60

Notes: The true age of mosquito groups is shown on the left while the mean predicted age (and variability, given as standard error of the mean, SEM) is shown on the right using standard Partial Least Squares (PLS) regression or a resampling PLS framework. Mosquitoes are classified as young (< 8 days) or old (≥ 8 days). First line of each section of the table shows the number of components used in the different models. Accuracy of age estimates is shown by the average difference between the true and predicted age measured in days (root-mean-square deviation, RMSD), with lowest values indicating a more accurate model. The ability to classifying mosquitoes as young or old is given by the area under the curve (AUC), with higher values indicating greater accuracy

ISSN: 1756-3305