The influence of weather on the population dynamics of common mosquito vector species in the Canadian Prairies

Abstract

Background Mosquito seasonal activity is largely driven by weather conditions, most notably temperature, precipitation, and relative humidity. The extent by which these weather variables influence activity is intertwined with the animal’s biology and may differ by species. For mosquito vectors, changes in weather can also alter host–pathogen interactions thereby increasing or decreasing the burden of disease. Methods In this study, we performed weekly mosquito surveillance throughout the active season over a 2-year period in Manitoba, Canada. We then used Generalized Linear Mixed Models (GLMMs) to explore the relationships between weather variables over the preceding 2 weeks and mosquito trap counts for four of the most prevalent vector species in this region: Oc. dorsalis, Ae. vexans, Cx. tarsalis, and Cq. perturbans. Results More than 265,000 mosquitoes were collected from 17 sampling sites throughout Manitoba in 2020 and 2021, with Ae. vexans the most commonly collected species followed by Cx. tarsalis. Aedes vexans favored high humidity, intermediate degree days, and low precipitation. Coquillettidia perturbans and Oc. dorsalis activity increased with high humidity and high rainfall, respectively. Culex tarsalis favored high degree days, with the relationship between number of mosquitoes captured and precipitation showing contrasting patterns between years. Minimum trapping temperature only impacted Ae. vexans and Cq. perturbans trap counts. Conclusions The activity of all four mosquito vectors was affected by weather conditions recorded in the 2 weeks prior to trapping, with each species favoring different conditions. Although some research has been done to explore the relationships between temperature/precipitation and Cx. tarsalis in the Canadian Prairies, to our knowledge this is the first study to investigate other commonly found vector species in this region. Overall, this study highlights how varying weather conditions can impact mosquito activity and in turn species-specific vector potential. Graphical Abstract

Identification of nectar sources foraged by female mosquitoes in Canada

“…Most of the nectar-fed mosquitoes captured were Ae. vexans , which was expected given it is the most pervasive species in the Canadian Prairies ( Brust and Ellis 1976 , Baril et al 2023 ). While the sample sizes were considerably smaller for the other barcoded species, it appears that their preferred nectar sources differed and may be associated with their life history.…”

“…Collections were carried out between June and August over a 2-year period (2020 and 2021), which was previously described ( Baril et al 2023 ). In brief, CDC Miniature Light Traps (Model 1012, John W. Hock, Gainesville, FL) with carbon dioxide regulators set at 15 psi (light disabled) were used to sample host-seeking mosquitoes from dawn to dusk.…”

“…In the Canadian Prairies, Aedes vexans Meigen is the most commonly found species ( Baril et al 2023 ). It is a competent vector of California serogroup viruses (CSGVs), Rift Valley fever virus, West Nile virus (WNV), and Zika virus ( Drebot 2015 , Weissmann 2016 , O’Donnell et al 2017 , Parry et al 2020 ).…”

Exposure dynamics of Ross River virus in horses – Horses as potential sentinels (a One Health approach)

“…It appears that seroconversion events occurred when the averaged air temperature was approximately between 18 °C and 25 °C. This is likely related to mosquito activities as larvae development and host-seeking activities are optimal between 15 °C and 32 °C [ 43 , 44 ], and as mosquito activity ceases when temperature falls below the minimum metabolic requirements [ 45 ]. In addition, percent change in wind gust was significantly associated with seroconversion.…”

Exploring Planetary Health Perspectives of Mosquito-borne Infections in Canada: A Rapid Scoping Review

“…The abundance and presence of mosquito species were impacted by several climatic variables, such as temperature, precipitation, humidity, and barometric pressure, with these factors affecting species differently (Khan et al, 2020;Baril et al, 2023;Chen et al, 2013a;Rakotoarinia, et al, 2022;Wang et al, 2011;Wang et al, 2014;Yoo et al, 2016;Dixon, et al, 1972). Temperature positively correlates with mosquito abundance, and it has a more immediate and lasting effect on the insects' abundance (day of and up to a month afterwards) (Khan, et al, 2020;Chen et al, 2013a;Wang, et al, 2011;Yoo, et al, 2016;Lysyk, 2010).…”