Evaluating the mosquito population dynamics using Human Landing and Human Double Net catches in a dengue emerging area; A case study from Sri Lanka

Human Landing Collection (HLC) and Human Double Net (HDN) trap are widely used adult mosquito sampling techniques that contribute to effective vector surveillance and dengue control planning. This study evaluated the effectiveness of HLC and HDN, mosquito species composition, and biting activity of dengue vectors in two dengue-endemic areas, Mawanella and Dehiovita (Kegalle District, Sri Lanka). Monthly collections were conducted from July 2023 to March 2024 using three HLC collectors and one HDN for 24-hour sampling per site. The total mosquito count (N = 807) varied significantly based on sampling method (HLC vs. HDN), locality, and species composition (P < 0.05, one-way ANOVA). HLC was the most effective sampling method, yielding the highest mosquito count (P < 0.05, t-test), with significantly higher mosquito abundance in Mawanella (P < 0.05, t-test). Among the collected mosquitoes, Culex spp. (n = 302) were the most abundant, followed by Armigeres spp. (n = 285), Aedes albopictus (n = 215), and Ae. aegypti (n = 5). The low abundance of Ae. aegypti suggests that Ae. albopictus is the primary dengue vector in the study area. The density of Ae. albopictus increased progressively from September onwards. Biting rate analysis revealed significant peaks from 06:00–09:00 and 15:00–18:00 hrs (P < 0.05, one-way ANOVA), with extended activity until 21:00 hrs. These findings highlight the need to schedule space-spraying interventions during peak biting hours and reinforce the importance of sustained personal protective measures in the evening. Additionally, integrating adult mosquito control with larval source reduction strategies is essential for comprehensive dengue vector management.