Influences of meteorological factors and seasonality on the population dynamics and wing plasticity of Culex mosquitoes (Diptera: Culicidae) in coconut plantations in central Thailand

Culex mosquitoes are important vectors of several pathogens that cause serious diseases. This study aimed to assess the effects of seasonal variation and meteorological factors on the population dynamics and wing phenotypic plasticity of Culex mosquitoes within coconut plantations in central Thailand. A total of 8,967 mosquitoes were collected, comprising 5,501 Culex sitiens, 3,464 Culex gelidus, and two Culex quinquefasciatus. Owing to the very low number of Cx. quinquefasciatus specimens, this species was excluded from further analyses. The highest mosquito abundance was recorded during the rainy season. Notably, Cx. gelidus exhibited a pronounced peak abundance in September, whereas Cx. sitiens reached its maximum abundance in May. A generalized linear model was applied to examine the influence of atmospheric pressure, rainfall, relative humidity, temperature, and wind speed on mosquito abundance. None of the variables had a significant effect (p > 0.05). Seasonal variation significantly influences wing phenotypic plasticity in Cx. gelidus and Cx. sitiens, with the largest average wing sizes observed in the cool season and the smallest in the rainy or hot seasons. All the seasonal populations of Cx. sitiens differed significantly in wing shape (p < 0.05). In Cx. gelidus, significant differences in wing shape occurred between the cool season and the hot and rainy seasons (p < 0.05) but not between the hot and rainy seasons (p > 0.05). These findings provide critical insights for improving mosquito-borne disease surveillance and enhancing targeted vector control strategies.