Odum School of Ecology, University of Georgia, 140 E Green St., Athens, Georgia, USA.
Center for the Ecology of Infectious Diseases, University of Georgia, 203 DW Brooks Dr, Athens, Georgia, 30602, USA.
Ecol Appl. 2021 Jul;31(5):e02334. doi: 10.1002/eap.2334. Epub 2021 Apr 27.
Invasive mosquitoes are expanding their ranges into new geographic areas and interacting with resident mosquito species. Understanding how novel interactions can affect mosquito population dynamics is necessary to predict transmission risk at invasion fronts. Mosquito life-history traits are extremely sensitive to temperature, and this can lead to temperature-dependent competition between competing invasive mosquito species. We explored temperature-dependent competition between Aedes aegypti and Anopheles stephensi, two invasive mosquito species whose distributions overlap in India, the Middle East, and North Africa, where An. stephensi is currently expanding into the endemic range of Ae. aegypti. We followed mosquito cohorts raised at different intraspecific and interspecific densities across five temperatures (16-32°C) to measure traits relevant for population growth and to estimate species' per capita growth rates. We then used these growth rates to derive each species' competitive ability at each temperature. We find strong evidence for asymmetric competition at all temperatures, with Ae. aegypti emerging as the dominant competitor. This was primarily because of differences in larval survival and development times across all temperatures that resulted in a higher estimated intrinsic growth rate and competitive tolerance estimate for Ae. aegypti compared to An. stephensi. The spread of An. stephensi into the African continent could lead to urban transmission of malaria, an otherwise rural disease, increasing the human population at risk and complicating malaria elimination efforts. Competition has resulted in habitat segregation of other invasive mosquito species, and our results suggest that it may play a role in determining the distribution of An. stephensi across its invasive range.
入侵蚊子正在向新的地理区域扩张，并与当地蚊子物种相互作用。了解新的相互作用如何影响蚊子种群动态，对于预测入侵前沿的传播风险是必要的。蚊子的生活史特征对温度极其敏感，这可能导致竞争入侵蚊子物种之间的温度依赖性竞争。我们探索了埃及伊蚊和致倦库蚊之间的温度依赖性竞争，这两种入侵蚊子的分布在印度、中东和北非重叠，致倦库蚊目前正在向埃及伊蚊的地方性分布区扩张。我们在五个温度（16-32°C）下，以不同的种内和种间密度饲养蚊子群体，以测量与种群增长相关的特征，并估计每个物种的个体增长率。然后，我们使用这些增长率来确定每个物种在每个温度下的竞争能力。我们在所有温度下都发现了强烈的非对称竞争证据，埃及伊蚊表现出更强的竞争力。这主要是由于在所有温度下幼虫存活率和发育时间的差异，导致埃及伊蚊的估计内在增长率和竞争耐受性估计值高于致倦库蚊。致倦库蚊在非洲大陆的传播可能导致疟疾在城市地区传播，而疟疾本来是一种农村疾病，这将增加处于危险中的人口，并使消除疟疾的努力复杂化。竞争导致了其他入侵蚊子物种的栖息地隔离，我们的结果表明，它可能在决定致倦库蚊在其入侵范围内的分布方面发挥作用。
