Increased Adult Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) Abundance in a Dengue Transmission Hotspot, Compared to a Coldspot, within Kaohsiung City, Taiwan.

Ka-Chon Ng,Luis Chaves,Ting-Wu Chuang,Kun-Hsien Tsai

doi:10.3390/insects9030098

Abstract

The assumption that vector abundance differences might drive spatial and temporal heterogeneities in vector-borne disease transmission is common, though data supporting it is scarce. Here, we present data from two common mosquito species Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say, biweekly sampled as adults, from March 2016 through December 2017, with BG-sentinel traps in two neighboring districts of Kaohsiung City (KC), Taiwan. One district has historically been a dengue transmission hotspot (Sanmin), and the other a coldspot (Nanzih). We collected a total 41,027 mosquitoes, and we found that average mosquito abundance (mean ± S.D.) was higher in Sanmin (Ae. aegypti: 9.03 ± 1.46; Cx. quinquefasciatus: 142.57 ± 14.38) than Nanzih (Ae. aegypti: 6.21 ± 0.47; Cx. quinquefasciatus: 63.37 ± 8.71) during the study period. In both districts, Ae. aegypti and Cx. quinquefasciatus population dynamics were sensitive to changes in temperature, the most platykurtic environmental variable at KC during the study period, a pattern predicted by Schmalhausen’s law, which states that organisms are more sensitive to small changes in environmental variables whose average value is more uncertain than its extremes. Our results also suggest that differences in Ae. aegypti abundance might be responsible for spatial differences in dengue transmission at KC. Our comparative approach, where we also observed a significant increment in the abundance of Cx. quinquefasciatus in the dengue transmission hotspot, suggests this area might be more likely to experience outbreaks of other vector borne diseases and should become a primary focus for vector surveillance and control.

Highlights

The yellow fever mosquito, Aedes aegypti (Linnaeus), and the southern house mosquito, Culex quinquefasciatus Say, are two of the most common urban mosquitoes in tropical and subtropical environments around the world [1,2,3]
Two highly urbanized and roads) districts of Kaohsiung City (KC)—Sanmin and Nanzih—were selected for the study
Our longitudinal mosquito data highlights the importance of high order environmental variability, measured by kurtosis, on forcing mosquito abundance fluctuations, a phenomenon observed elsewhere for Ae. aegypti [32,39], Cx. quinquefasciatus [81,82,83] and other mosquito species [23,38,71,84], with patterns following the prediction of Schmalhausen’s law, the biological principle stating that organisms are sensitive to average environmental conditions and to the environmental variability per se [25]

Summary

Introduction

The yellow fever mosquito, Aedes aegypti (Linnaeus), and the southern house mosquito, Culex quinquefasciatus Say, are two of the most common urban mosquitoes in tropical and subtropical environments around the world [1,2,3]. Cx. quinquesfaciatus is one of the few species where impacts of global warming on its overwintering patterns have been observed in subtropical environments [11], while. Ae. aegypti is a species whose distribution seems to be expanding as a result of global warming [12,13,14]. With changing climatic patterns, increased movement of people and goods, and unplanned urbanization, the transmission risk of vector-borne diseases has seen an unprecedented growth across the globe [15,16,17].

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