Cross-Correlation Map Analyses Show Weather Variation Influences on Mosquito Abundance Patterns in Saginaw County, Michigan, 1989–2005

Abstract

Weather is important determinant of mosquito abundance that, in turn, influences vectorborne disease dynamics. In temperate regions, transmission generally is seasonal as mosquito abundance and behavior varies with temperature, precipitation, and other meteorological factors. We investigated how such factors affected species-specific mosquito abundance patterns in Saginaw County, MI, during a 17-yr period. Systematic sampling was undertaken at 22 trapping sites from May to September, during 1989-2005, for 19,228 trap-nights and 300,770 mosquitoes in total. Aedes vexans (Meigen), Culex pipiens L. and Culex restuans Theobald, the most abundant species, were analyzed. Weather data included local daily maximum temperature, minimum temperature, total precipitation, and average relative humidity. In addition to standard statistical methods, cross-correlation mapping was used to evaluate temporal associations with various lag periods between weather variables and species-specific mosquito abundances. Overall, the average number of mosquitoes was 4.90 per trap-night for Ae. vexans, 2.12 for Cx. pipiens, and 1.23 for Cx. restuans. Statistical analysis of the considerable temporal variability in species-specific abundances indicated that precipitation and relative humidity 1 wk prior were significantly positively associated with Ae. vexans, whereas elevated maximum temperature had a negative effect during summer. Cx. pipiens abundance was positively influenced by the preceding minimum temperature in the early season but negatively associated with precipitation during summer and with maximum temperature in July and August. Cx. restuans showed the least weather association, with only relative humidity 2-24 d prior being linked positively during late spring-early summer. The recently developed analytical method applied in this study could enhance our understanding of the influences of weather variability on mosquito population dynamics.

Predicting Culex pipiens/restuans population dynamics by interval lagged weather data

“…Mosquito capture rates increased with increasing temperature, as already shown in previous studies [5,6]. Furthermore, it has been demonstrated that considerable changes in the temperature at the capture event compared to the previous days affect the number of captured mosquitoes.…”

“…Previous studies have already confirmed that population densities vary strongly with temperature [5,6]. This is due to the temperature dependence of the development rates of eggs, larvae and pupae, survival rates of immatures as well as imagos.…”

“…The duration of the aquatic stages also varies with temperature, and weather conditions from about 8 to 20 days prior to capture presumably affect the aquatic stage [7]; weather conditions from about 20 to 28 days affect the adult stage of the parent generation. Previous studies with CCMs considered a time period of about 4 weeks, which approximately represents the lifetime of a mosquito, inclusive all aquatic stages [5,18,19]. The results of this study however show that environmental factors have to be considered further back in time.…”

“…pipiens/restuans population dynamics, as high rainfall occurring several weeks before a capture event was positively correlated with the mosquito abundance [5,6]. The accurate mechanisms behind this relationship however are less well understood.…”

Investigation of pharmaceuticals, personal care products and endocrine disrupting chemicals in a tropical urban catchment and the influence of environmental factors

“…In addition, the temporal variations can probably be traced back to usage patterns. The insect repellent DEET is widely used not only in households but also with outdoor recreational activities and its usage may increase as a result of higher abundance of mosquitoes during the monsoons and high humidity periods (Chuang et al, 2012), leading to the relatively higher loads. We assign the variation of caffeine concentrations in the reservoir to rainfall, but other frequently detected wastewater indicators, such as salicylic acid and crotamiton, showed no dependence with cumulative precipitation.…”