Spatial Distribution, Seasonal Abundance and Physio-Chemical Assessment of Mosquito Larval Breeding Sites in Mardan District, Khyber Pakhtunkhwa, Pakistan

Abstract

Background: Mosquitoes (Diptera: Culicidae) are haemotophagus insects and are vectors of many arthropod-borne diseases. Present study aimed to explore species composition, seasonal abundance, spatial distribution and physio-chemical properties of larval breeding sites of mosquitoes in District Mardan, Khyber Pakhtunkhwa, Pakistan.

Methods: Both adults and larvae of mosquitoes were collected through light traps, insecticide spray, mouth aspirator and larval standard dipping method in District Mardan from May to November 2017. Water samples from larval sites were physio-chemically analysed.

Results: 5078 (3704 adults and 1374 larvae) mosquito specimens were collected in Mardan, Katlang and Takhtbhai tehsils. Six species in four genera were reported. Culex pipiens (89.80%) and Armigeres subalbatus (9.20%) were the most abundant species. Diversity was high in Takhtbhai (0.29) followed by Katlang (0.28) and Mardan (0.25). Greater number of specimens were recorded in peridomestic sites (93.97%) as compared to domestic habitats (6.03%). Culex pipiens larval abundance had negative correlation with pH whereas it correlated positively with electric conductivity, salinity, and TDS (total dissolved sulphur). Mosquito abundance peaked in August and July while the lowest was in May. Their monthly abundance had positive correlation with rainfall (r= 0.5069), relative humidity (r= 0.4439) and mean minimum temperature (r= 0.2866). Number of mosquitoes was highest at low elevation < 347m asl (above sea level) in agriculture land and near to water bodies (streams).

Conclusion: Culex pipiens being the most abundant species, was susceptible to high pH. Mosquitoes preferred habitats were at low elevation in agriculture land.