Figure 1Distribution of mosquitoes and Culex tritaeniorhynchus (CT) per year.
Figure 2Autocorrelation.
Figure 3Out-of-sample results used in rolling window regression (weekly data). CT, Culex tritaeniorhynchus. RC: Rolling window regression of CT.
Figure 4Out-of-sample results used in adding window regression (weekly data). CT, Culex tritaeniorhynchus. AC: Adding window regression of CT.
Table 1Unit root test (level variables).
Weekly data |
ADF
|
PP
|
None |
Intercept |
Trend |
None |
Intercept |
Trend |
All mosquitoes |
−5.423* |
−6.190* |
−6.246* |
−5.655* |
−6.672* |
−6.751* |
Culex tritaeniorhynchus
|
−8.786* |
−9.529* |
−9.549* |
−6.862* |
−7.708* |
−7.720* |
Ratio |
−6.177* |
−7.340* |
−7.336* |
−5.771* |
−6.708* |
−6.705* |
Table 2Basic statistical data on mosquito density.
Variables |
Mean |
Maximum value |
Minimum value |
Standard deviation |
All mosquitoes |
7846.3(562.9)* |
87,194.0 |
0.0 |
14,635.1 |
Culex tritaeniorhynchus
|
1991.9(217.0)* |
58,769.0 |
0.0 |
5641.4 |
Ratio |
10.2(0.7)* |
73.4 |
0.0 |
17.7 |
Table 3Time lag test.
Variables |
All mosquitoes |
Culex tritaeniorhynchus
|
Ratio of Culex tritaeniorhynchus to all mosquitoes |
Test method |
AIC |
SIC |
AIC |
SIC |
AIC |
SIC |
Time lag |
10 |
1 |
4 |
4 |
9 |
4 |
Table 4Autoregressive model estimation (weekly data).
Variable |
Last year |
2 years ago |
3 years ago |
4 years ago |
R2
|
All mosquitoes |
0.435(0.044)** |
0.269(0.054)** |
−0.024(0.056) |
0.310(0.055)** |
0.637 |
Japanese encephalitis |
0.138(0.043)** |
0.353(0.043)** |
0.189(0.050)** |
0.068(0.049) |
0.394 |
Ratio of Japanese encephalitis |
0.162(0.044)** |
0.381(0.041)** |
0.381(0.044)** |
−0.085(0.045)*** |
0.717 |
Table 5MSE of in-sample.
|
In-sample prediction
|
All mosquitoes |
Culex tritaeniorhynchus
|
Ratio |
MSE |
8.881 × 107
|
1.851 × 107
|
84.823 |
Table 6MSPE of out-of-sample prediction.
|
Out-of-sample prediction
|
All mosquitoes |
Culex tritaeniorhynchus
|
Ratio of Culex tritaeniorhynchus
|
MSPE (RO) |
2.045 × 108
|
8.852 × 107
|
86.069 |
MSPE (AD) |
5.229 × 107
|
3.476 × 107
|
78.351 |