Table 4 Seasonal variation in Anopheles larval densities over a 12-month sampling period among different aquatic habitats in three study sites in Mwea, Kenya (Density is expressed as number of larvae per 10 dips)
| Â | Â | Month | Â | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Village | Habitat type | Apr | May | Jun | Jul | Aug | Sept | Oct | Nov | Dec | Jan | Feb | Mar | Mean |
Mbui Njeru | Canal | 0.7 | 0.7 | 0.1 | 1.1 | 0.3 | 2.5 | 1.3 | 1.6 | 1.4 | 1.1 | 1.0 | 1.0 | 1.05 |
| Â | Marsh | 0.0 | 0.0 | 0.2 | a- | 0.7 | - | 2.1 | 1.0 | 0.0 | - | 0.7 | 16.7 | 1.78 |
| Â | Rice field | 2.2 | 0.7 | 1.0 | 0.7 | 1.4 | 6.0 | 3.0 | 0.4 | 4.2 | 2.0 | 3.0 | 4.4 | 2.41 |
| Â | Temporary pool | 7.9 | 2.9 | 0.5 | - | 0.9 | 0.7 | 0.5 | 1.1 | 1.8 | 0.3 | 0.1 | 0.5 | 1.42 |
| Â | Water reservoir | 0.0 | - | - | - | - | - | 0.0 | 0.0 | 2.7 | - | - | 0.0 | 0.22 |
| Â | Rainfall | 205.6 | 47.3 | 8 | 0 | 0 | 18 | 141.8 | 231 | 63.5 | 22.5 | 16.9 | 48.5 | 66.93 |
| Â | Total larvae | 10.8 | 4.3 | 1.8 | 1.8 | 3.3 | 9.2 | 6.9 | 4.1 | 10.1 | 3.4 | 4.8 | 22.6 | 6.88 |
Kiamachiri | Canal | 1.4 | 0.1 | 0.4 | 1.1 | 2.0 | 2.8 | 4.9 | 3.7 | 1.7 | 3.0 | 1.3 | 1.4 | 1.99 |
| Â | Marsh | 1.1 | 0.5 | 1.2 | 2.7 | 2.7 | 1.8 | 1.3 | 4.2 | 4.0 | 2.5 | 2.2 | 2.0 | 2.18 |
| Â | Rice field | 2.1 | 1.3 | 1.7 | 1.4 | 1.8 | 7.9 | 4.5 | 7.3 | 8.6 | 9.8 | 3.0 | 6.2 | 4.64 |
| Â | Temporary pool | 1.9 | 2.0 | 1.8 | 0.9 | 0.2 | 3.2 | 0.6 | 6.9 | 2.8 | 2.4 | 1.7 | 0.7 | 2.09 |
| Â | Water reservoir | 0.2 | 0.0 | 1.3 | 0.0 | - | - | 1.0 | 1.8 | 0.0 | 2.0 | 0.0 | - | 0.52 |
| Â | Rainfall | 181.8 | 74.8 | 28 | 8 | 1.6 | 71 | 96.2 | 136 | 47.5 | 21 | 1 | 13 | 56.66 |
| Â | Total larvae | 6.7 | 3.9 | 6.4 | 6.1 | 6.7 | 15.7 | 12.3 | 23.9 | 17.1 | 19.7 | 8.2 | 10.3 | 11.42 |
Murinduko | Canal | 2.5 | 2.8 | 4.9 | 4.9 | 17.9 | 8.0 | 3.4 | 1.8 | 2.9 | 3.9 | 4.9 | 8.9 | 5.58 |
| Â | Marsh | 2.3 | 5.7 | 6.8 | 3.9 | 8.2 | 27.1 | 9.4 | 7.9 | 3.9 | 4.2 | 6.6 | 8.5 | 7.86 |
| Â | Rice field | 2.1 | 3.8 | 11.3 | 6.1 | 12.0 | 16.3 | 6.9 | 5.1 | 4.1 | 6.9 | 7.4 | 11.2 | 7.77 |
| Â | Rock pool | 3.0 | 3.4 | - | - | - | - | 13.0 | 9.5 | 3.5 | - | - | - | 2.70 |
| Â | Stream pool | 7.6 | 3.5 | 10.5 | 3.9 | 11.8 | 5.0 | 3.0 | 3.5 | 5.7 | 8.6 | 14.2 | 14.3 | 7.64 |
| Â | Temporary pool | 8.5 | 1.4 | 12.7 | 7.1 | 6.8 | 11.0 | 9.3 | 21.9 | 8.6 | 9.2 | 8.8 | 5.0 | 9.18 |
| Â | Tree hole | 0.0 | 0.0 | 0.0 | - | - | - | 0.0 | 0.0 | 0.8 | 9.0 | - | - | 0.82 |
| Â | Water reservoir | 0.5 | 0.0 | - | - | - | - | 0.0 | 8.7 | 9.0 | 0.0 | 0.0 | 0.0 | 1.51 |
| Â | Rainfall | 119 | 56 | 10 | 0 | 9 | 15 | 190 | 324 | 54 | 6 | 4 | 23 | 67.5 |
| Â | Total larvae | 26.5 | 20.6 | 46.2 | 25.9 | 56.7 | 67.4 | 45.0 | 58.4 | 38.5 | 41.8 | 41.9 | 47.9 | 43.06 |