Departamento de Epidemiologia, Faculdade de Saúde Pública, Universidade de São Paulo, São Paulo, Brazil.
Department of Public Health Sciences, Miller School of Medicine, University of Miami, Miami, FL, USA.
Parasit Vectors. 2018 Oct 26;11(1):561. doi: 10.1186/s13071-018-3154-4.
Aedes aegypti is the main vector of the dengue, Zika and several other arboviruses. It is highly adapted to urbanized environments and can be found worldwide. Mosquito population control is considered the best strategy for fighting mosquito-borne diseases, making an understanding of their population dynamics vital for the development of more effective vector control programs. This study therefore sought to investigate how different levels of urbanization affect Aedes aegypti populations and modulate population structure in this species with the aid of wing geometric morphometrics.
Specimens were collected from eleven locations in three areas with distinct levels of urbanization in the city of São Paulo, Brazil: conserved, intermediate and urbanized. The right wings of female mosquitoes collected were removed, and photographed and digitized. Canonical variate analysis and Mahalanobis distance were used to investigate the degree of wing-shape dissimilarity among populations. Thin-plate splines were calculated by regression analysis of Canonical Variation Analysis scores against wing-shape variation, and a cross-validated reclassification was performed for each individual; a neighbor-joining tree was then constructed.
Metapopulation and individual population analysis showed a clear segregation pattern in the Canonical Variation Analysis. Pairwise cross-validated reclassification yielded relatively high scores considering the microgeographical scale of the study and the fact that the study populations belong to the same species. The neighbor-joining tree showed that mosquitoes in the intermediate urban area segregated in the metapopulation and individual population analyses. Our findings show significant population structuring in Aedes aegypti mosquitoes in the areas studied. This is related to the different degrees of urbanization in the areas where the specimens were collected along with their geographical location.
Urbanization processes in the study areas appear to play an important role in microevolutionary processes triggered by man-made modifications in the environment, resulting in a previously unknown population structuring pattern of major epidemiological importance.
埃及伊蚊是登革热、寨卡病毒和其他几种虫媒病毒的主要传播媒介。它高度适应城市化环境，分布于世界各地。蚊虫种群控制被认为是防治蚊媒疾病的最佳策略，因此了解其种群动态对于制定更有效的病媒控制计划至关重要。本研究旨在借助翅几何形态测量学，探讨不同城市化水平如何影响埃及伊蚊种群，并调节该物种的种群结构。
从巴西圣保罗市三个城市化水平不同的区域的 11 个地点收集标本：保护区、中间区和市区。采集的雌性蚊子的右翅被取下，进行拍照和数字化。使用典型变量分析和马氏距离来研究种群间翅形差异程度。通过对典型变量分析得分与翅形变化的回归分析计算薄板样条，并对每个个体进行交叉验证再分类；然后构建了一个邻接聚类树。
集合种群和个体种群分析表明，在典型变量分析中存在明显的分离模式。成对的交叉验证再分类得分考虑到研究的微地理尺度以及研究种群属于同一物种的事实，相对较高。邻接聚类树表明，中间市区的蚊子在集合种群和个体种群分析中分离。我们的研究结果表明，在所研究的地区，埃及伊蚊蚊子存在明显的种群结构。这与样本采集地区的城市化程度不同以及地理位置有关。
研究区域的城市化进程似乎在由人为环境改变引发的微进化过程中发挥了重要作用，导致了以前未知的具有重要流行病学意义的种群结构模式。
