Broadscale spatial synchrony in a West Nile virus mosquito vector across multiple timescales

Abstract Insects often exhibit irruptive population dynamics determined by environmental conditions. Here, we examine if populations of the Culex tarsalis mosquito, an important vector for West Nile virus (WNV), fluctuate synchronously over broad spatial extents and multiple timescales. We also examine whether climate drives synchrony in Cx. tarsalis, especially at annual time scales, due to the synchronous influence of temperature, precipitation, and/or humidity. We leveraged mosquito collections from National Earth Observatory Network (NEON) sites in the USA over a 45-month period, and associated gridMET climate data. We utilized wavelet phasor mean fields and wavelet linear models to quantify spatial synchrony for mosquitoes and climate and to calculate the importance of climate in explaining Cx. tarsalis synchrony. We also tested whether the strength of spatial synchrony may vary directionally across years. We found significant annual synchrony in Cx. tarsalis, and short-term synchrony during a single time period in 2018. Mean minimum temperature was a marginally significant predictor of annual Cx. tarsalis synchrony, and we found a marginally significant decrease in annual Cx. tarsalis synchrony. Significant Cx. tarsalis synchrony during 2018 coincided with an anomalous increase in precipitation. This work provides a valuable step toward understanding broad scale synchrony in a WNV vector.