Relative Productivity of Mosquito Larval Habitats for Abundance and Immature stages Distribution in Relation to Physicochemical Properties in Niger State, Nigeria

Abstract

Immature mosquitoes were evaluated for the productivity of the breeding habitats using field cages in Niger State. Mosquitoes were sampled weekly both outside and inside field experimental cages by dipping and emptying the cages in a bowl container and identified using microscope-guided standard morphological keys. Three genera namely, Aedes, Anopheles, and Culex, were encountered and the mean immature abundance rate (IAR), in gutters, follows decreasing order and dominated by Culex (93.16±10.79%) > Anopheles (17.79±2.23%) > Aedes (15.77±2.12 %). In swamps, Anopheles highest mean (78.04±8.00%), followed by Culex (28.13±2.55%) and Aedes(14.54±1.56%). Similarly, in large water bodies, the distribution decreases as; Anopheles (74.33±7.07%)> Culex (27.14±2.50%)>Aedes (12.91±1.30%). In terms of immature productivity rate (IPR) among the three genera, Culex had the highest mean in gutters (191.29±22.37%) followed by Anopheles in large waters and swamps (148.03±14.81% and 153.15±15.92%) while lowest was Aedes (25.57±2.42%) in large water. Furthermore, for the density of immature, 1st stage (L1) recorded the highest followed by 2nd stage (L2), followed by 3rd stage (L3), and the least was the 4th stage (L4) for IAR and IPR. For the estimation of breeding habitats, the cage sampling method is the most reliable (709.86±73.63 mosquitoes) when compared with dipping techniques that recorded 324.06±44.00 mosquitoes. Mosquito physicochemical conditions varied significantly with DO (8.83±0.40) in large water bodies; nitrate (4.57±0.55), phosphate (3.26±0.73), calcium (88.19±12.79), sulphur (28.23±2.45), potassium (10.63±0.76), chlorine (87.52±20.89) and alkalinity (187.00±26.39) in the gutters. However, a positive correlation between rainfall and mosquito species (r = 0.523 to 0.801) as well as between relative humidity and mosquitoes (r= 0.236 to 0.551, p>0.05) on mosquito populations. Only Anopheles in large water habitats was significant (0.801*, p>0.05). The findings revealed disparities in the abundance and larval habitat production rates of the mosquito genera and associated positively with some physicochemical and metrological cues. Consequently, an effective tactic must be developed for mosquito control, particularly in the most highly recognized breeding habitats.